Variation in metabolite profiles of Haematococcus pluvialis(a type of unicellular green algal)under light stress is a key issue of study at the present.To investigate the effect of light intensity on accumulation of a...Variation in metabolite profiles of Haematococcus pluvialis(a type of unicellular green algal)under light stress is a key issue of study at the present.To investigate the effect of light intensity on accumulation of astaxanthin in H.pluvialis,a 26-day batch culture experiment of H.pluvialis under the light intensity levels at 73,127,182,236,and 291μmol/(m^(2)·s)was conducted.Therefore,the optimal light intensity and the corresponding metabolic pathways of accumulation in H.pluvialis were determined.Results show that 236μmol/(m^(2)·s)was the optimum light intensity to induce astaxanthin accumulation,at which a maximum content of 9.01 mg/L was achieved on Day 24.A total of 132 metabolites were identified and quantified,of which 38 differential metabolites were highlighted and classified,including 3 fatty acids or intermediates,5 amino acids or derivatives,5 carbohydrates or intermediates,16nucleoside derivatives,and 9 other metabolites using LC-MS/MS technique.Subsequently,16 statistically significant differential metabolic pathways were enriched and annotated based on Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis between the control and the 236μmol/(m^(2)·s)treatment group(P<0.05).In addition,the bioprocesses included cellular basal metabolism and signaling systems,such as carbohydrate metabolism,amino acid metabolism,glycerol and derivatives metabolism,nucleotide and derivative metabolism,and inositol phosphate metabolism were activated and regulated under strong light stress conditions.Moreover,4 hub metabolites containing D-glucose-6-phosphate,L-tyrosine,glycerol-3-phosphate,and L-glutamine were identified,based on which the associated metabolic network was constructed.The study provided a metabolomic view of astaxanthin accumulation in H.pluvialis under strong light stress.展开更多
Docosahexaenoic acid-acylated astaxanthin(DHA-AST)esters exhibit distinct bioactivities in improving brain function.However,the digestion and absorption characteristics of DHA-AST esters in vivo are unclear,thereby re...Docosahexaenoic acid-acylated astaxanthin(DHA-AST)esters exhibit distinct bioactivities in improving brain function.However,the digestion and absorption characteristics of DHA-AST esters in vivo are unclear,thereby restricting the molecular mechanism analysis of their superior activities.This study compared the digestion and absorption characteristics of DHA-AST monoester and diester by determining the levels of AST and DHA in the serum,liver,small intestinal content and wall,and feces at different time points after a single-dose oral administration of the esters.After oral gavage with 2 mg AST equivalent of the DHA-AST monoester and diester for 18 h,the excretion rates were approximately 51%and 84%,respectively.This result indicates that DHA-AST monoester was better than diester for the absorption of AST.The results in serum,liver,and small intestinal content and wall also agreed with this finding.Moreover,the excretion rates of DHA in the feces at 24 h in the DHA-AST monoester and diester groups were approximately 40%and 36%after gavage with 5 mg DHA equivalent,respectively.This result indicates that DHA-AST diester exhibited a better tendency than monoester for the absorption of DHA.Interestingly,the results in the liver and small intestinal wall showed an apparent difference,indicating that DHA-AST diester was better than monoester for the absorption of DHA.These findings provide a scientific basis for the molecular mechanism analysis and utilization of DHA-AST monoester and diester as functional ingredients.展开更多
The optimum concentration of Na_2 WO_4 was explored in relation to the cell density and astaxanthin content in Haematococcus pluvialis. Then, the cellular morphology, nitrate reductase(NR) activity, soluble sugar and ...The optimum concentration of Na_2 WO_4 was explored in relation to the cell density and astaxanthin content in Haematococcus pluvialis. Then, the cellular morphology, nitrate reductase(NR) activity, soluble sugar and protein contents, and chlorophyll ?uorescence were measured, and the transcriptional expression of carotenogenic genes was determined by quantitative real-time PCR. The results showed that 3.0 mmol/L of Na_2 WO_4 was the optimum concentration to induce astaxanthin accumulation, with a maximum content of 49.41±0.13 pg/cell reached on the tenth day. The NR activity decreased signi?cantly and continually after Na_2 WO_4 treatment. The soluble sugar content increased gradually during the experimental period and was eventually signi?cantly higher than that in the control. The soluble protein content increased rapidly,reached a maximum in day 0.5 and day 1 and then decreased. The ef fective photochemical effciency of PSII( F v'/F m') and light saturation( E k) ?rst decreased and then tended to stabilize, and NADP +-glyceraldehyde-3-phosphate dehydrogenase(GAPDH) gene expression was correlated with photosynthesis. The transcriptional expression of ipi, psy and bkt was signi?cantly increased compared with that in the control after application of Na_2 WO_4, and the relative expression of ipi reached the highest level on the ?fth day, with a 98.03±1.92-fold increase. Our results describe a new approach to promote the ef fective accumulation of astaxanthin in H. pluvialis by NR inhibitor Na_2 WO_4.展开更多
AIM:To characterize effect of astaxanthin(ASX)in Aspergillus fumigatus(A.fumigatus)induced keratitis in mouse model.METHODS:In vivo,fungal keratitis mouse model was established in C57BL/6 mice using A.fumigatus,follow...AIM:To characterize effect of astaxanthin(ASX)in Aspergillus fumigatus(A.fumigatus)induced keratitis in mouse model.METHODS:In vivo,fungal keratitis mouse model was established in C57BL/6 mice using A.fumigatus,followed by ASX or dimethyl sulfoxide(DMSO)treatment.Clinical responses were evaluated by clinical score and myeloperoxidase(MPO)assay.Inflammatory cytokines were assessed by reverse-transcription polymerase chain reaction(RT-PCR),Western blot,immunofluorescence,and enzyme-linked immuno sorbent assay(ELISA).RESULTS:In animal model,ASX improved corneal transparency and clinical response,suppressed the expression of inflammatory cytokine like IL-1β,TNF-α,and HMGB-1.Neutrophil levels have been shown to decrease in ASX-treated cornea by immunofluorescence and MPO.TLR2 and TLR4 levels were lower in ASX-treated group than DMSO-treated.CONCLUSION:ASX can suppress inflammatory response and reduce inflammatory cytokine production in mice model with A.fumigatus keratitis.展开更多
Background:Natural astaxanthin(ASTA)has strong antioxidant properties and has been widely used as a health product to improve human health.However,the effects of ASTA on the reproductive performance of aging roosters ...Background:Natural astaxanthin(ASTA)has strong antioxidant properties and has been widely used as a health product to improve human health.However,the effects of ASTA on the reproductive performance of aging roosters have been poorly studied.We aimed to investigate the effects of dietary ASTA on semen quality and antioxidant capacity in aging roosters and to explore the potential mechanism of semen quality change via antioxidation defense system.Methods:In the present study,9653-week-old Jinghong No.1 layer breeder roosters were fed a corn-soybean meal basal diet containing 0,25,50,or 100 mg/kg ASTA for 6 weeks.Results:Semen quality in the ASTA groups remarkably improved than that in the control group,and antioxidant activities,the abilities to scavenge hydroxyl radicals and superoxide anions,increased gradually with ASTA addition(P<0.05).In addition,the mRNA levels of antioxidant enzymes as well as the mRNA and protein levels of the mitogen-activated protein kinase(MAPK)and nuclear factor-erythroid 2-related factor 2(Nrf2)were markedly increased in the 50-100 mg/kg ASTA group(P<0.05).Conclusions:Collectively,these results demonstrate that dietary ASTA may improve semen quality by increasing antioxidant enzyme activities and the ability to scavenge hydroxyl radicals,which may be related to upregulation of the MAPK/Nrf2 pathway.展开更多
Astaxanthin is a value-added ketocarotenoid with great potential in nutraceutical and pharmaceutical industries.Genetic engineering of heterologous hosts for astaxanthin production has attracted great attention.In thi...Astaxanthin is a value-added ketocarotenoid with great potential in nutraceutical and pharmaceutical industries.Genetic engineering of heterologous hosts for astaxanthin production has attracted great attention.In this study,we assessed some key factors,including codon usage of the expressed genes,types of promoters,bacterial strains,and culture media,for engineered Escherichia coli to produce astaxanthin.The effect of codon usage was shown to be related to the types of promoters.E.coli DH5a was superior to other strains for astaxanthin production.Different culture media greatly affected the contents and yields of astaxanthin in engineered E.coli.When the expression cassette containing GadE promoter and its driving genes,HpCHY and CrBKT,was inserted into the plasmid pACCAR16DcrtX and expressed in E.coli DH5a,the engineered strain was able to produce 4.30±0.28 mg/g dry cell weight(DCW)or 24.16±2.03 mg/L of astaxanthin,which was a sevenfold or 40-fold increase over the initial production of 0.62±0.03 mg/g DCW or 0.61±0.05 mg/L.展开更多
Given the central role of light in the algal photosynthesis,respiration,cell division,growth and the accumulation of value products,the effects of light-emitting diodes(LEDs)light wavelengths(blue,white,red and green)...Given the central role of light in the algal photosynthesis,respiration,cell division,growth and the accumulation of value products,the effects of light-emitting diodes(LEDs)light wavelengths(blue,white,red and green)were studied in Scenedesmus obliquus.Biomass,residual nutrient amount,soluble protein,astaxanthin and reactive oxygen species,superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)activity were analyzed to determine the effects of different monochromatic light wavelengths via biochemical methods.The results showed that blue light wavelength is the optimal light wavelength for phosphorus removal efficiency and the accumulation of biomass and astaxanthin in S.obliquus.Meanwhile,high reactive oxygen species content under the blue light might induce the accumulation of astaxanthin.The high activity of SOD,CAT and POD might participate in clearing the reactive oxygen species to facilitate the growth of microalgae.Furthermore,we found mixed blue/green lights treatment is the most appropriate mixture for the nitrogen removal.Under the blue light treatment,high light intensity and 18L:6D light cycle is the best condition for biomass and astaxanthin accumulation.Optimal nitrogen/phosphorus removal efficiency was observed under a 24L:0D light cycle.These results might provide a foundational data for the optimizing the productivity of high-value metabolites and treatment of wastewater.展开更多
AIM: To observe the protective effect of astaxanthin(AST) against hydroquinone(HQ) mediated cell death in the apoptotic cascade and evaluate intracellular Ca2+ release, caspase-3, and-9 activation, reactive oxygen spe...AIM: To observe the protective effect of astaxanthin(AST) against hydroquinone(HQ) mediated cell death in the apoptotic cascade and evaluate intracellular Ca2+ release, caspase-3, and-9 activation, reactive oxygen species(ROS) production in ARPE-19 cells.METHODS: We cultured ARPE-19 cells in special mediums and performed MTT tests to determine protective effect of AST, before exposing the cells to HQ in an incubator. We analyzed intracellular Ca2+ release experiments, mitochondrial membrane depolarization, glutathione(GSH), glutathione peroxidase(GSH-Px) and ROS experiments, and apoptosis assay.RESULTS: ROS production ranges depend on the amount of cell death. We computed the correlation between ROS ranges and cell death by 20,70-dichlorofluorescein fluorescence, and Ca2+ levels by Fura-2-AM. HQ-induced cell death found out to rise ranges of caspase-3 and-9, and mitochondrial depolarization. These three steps were delayed by AST management.CONCLUSION: ARPE-19 cells are avoided from HQinduced ROS production and caspase-3 and-9 activation by AST. AST may limit the range of caspase synthesis, Ca2+ release and excess production of ROS with antiapoptotic effect. This study proposes a new therapeutic approach for the treatment of age-related macular degeneration.展开更多
Astaxanthin （ATX） , the most abundant flavonoids in propolis, has been proven to exert neuroprotective property against cerebral ischemia-induced apoptosis. However, the mechanisms by which ATX mediates its thera- p...Astaxanthin （ATX） , the most abundant flavonoids in propolis, has been proven to exert neuroprotective property against cerebral ischemia-induced apoptosis. However, the mechanisms by which ATX mediates its thera- peutic effects in vitro are unclear. In the present study, the article explored the underlying mechanisms involved in the protective effects of ATX via the PI3IC/Akt/GSK3β/Nrf2 signaling pathway in SH-SY5Y cells. For study of mechanism, the phosphoinositide 3 kinase （PI3K）-Akt inhibitor LY294002, Glycogen synthase kinase 3β （GSK313） inhibitor LiC1 were used. Pre-treatmentwith ATX for 24h significantly reduced the OGD induced viability loss, apoptotic rate and attenuated OGD-mediated ROS production. In addition, ATX inhibited OGD-induced mito- chondrial membrane potential, decreased Bcl-2/Bax ratio. PI3 IC/Akt/GSK3β/Nrf2 signaling pathway activation in SH-SY5Y was tested by Western blot. Nrf2 expression was increasing by ATX and counteracted by PI3IC/Akt in- hibitor LY294002, GSK3β inhibitor LiC1 in SH-SY5Y. Nrf2 Immunocytochemistry showed Nrf2 nuclear transloca- tion was increasing by ATX and counteracted by LY294002 or LiC1 in SH-SY5Y, respectively. It may be suggested that astaxanthin against cerebral ischemia-induced apoptosis in vitro via a programmed PI3 IC/Akt/GSK3β/Nrf2 sig- naling pathway in vitro.展开更多
Alzheimer’s Disease is projected to increase to 30 million people in the next 30 years and the rate of diabetes mellitus is projected to rise also. Hyperglycemia is commonly observed in patients with diabetes mellitu...Alzheimer’s Disease is projected to increase to 30 million people in the next 30 years and the rate of diabetes mellitus is projected to rise also. Hyperglycemia is commonly observed in patients with diabetes mellitus, and hypoglycemia is a common consequence due to insulin therapy. Previous research has shown a potential link between Alzheimer’s disease and diabetes. This study sought to determine if Astaxanthin (ATX) could prevent mitochondrial dysfunction from the compounded effects of amyloid β (Aβ) plaque and hypoglycemia or hyperglycemia. Growth patterns, ATP production, and ROS generation were examined in 2 μM, 5 μM, 25 μM (hypoglycemic groups), 2 mM, 5 mM (normal groups), and 25 mM glucose (hyperglycemic group), and then treated with or without ATX or Aβ. When hypoglycemia groups and the hyperglycemia group were treated with ATX, their growth patterns were either comparable to control or increased. ATX and Aβ treated cells demonstrated increased growth patterns over cells treated with Aβ alone. Aβ alone treated groups overall had significantly less growth than controls (p β demonstrated low levels of average fluorescence generated by ROS production as determined by MitoSox assay while ATX groups actually produced higher to normal levels of ROS. Cells grown in the presence of Aβ and ATX generally produced more ROS than just Aβ groups. Thus, hypoglycemia and hyperglycemia do appear to compound the effects of Aβ on hippocampal cells. ATX treatment demonstrated promise with increased cellular growth, which promoted usage of ATP by the cell and ROS production. This growth was present even in the presence of Aβ, suggesting that ATX is able to overcome the negative effects of Aβ.展开更多
This study was designed to investigate the protective effects of Astaxanthin(AST)in rats with diabetes mellitus(DM)induced by streptozotocin.SD rats were divided into control group(n=5,only received normal saline),DM ...This study was designed to investigate the protective effects of Astaxanthin(AST)in rats with diabetes mellitus(DM)induced by streptozotocin.SD rats were divided into control group(n=5,only received normal saline),DM group(n=8)and AST+DM group(n=8;AST:50 mg/kg/day).DM rats were induced by intraperitoneal injection of streptozocin(STZ,65 mg/kg).Blood glucose level and body weight were determined at weeks 0,2,4,6 and 8,respectively.At week 8,kidney function was determined,together with expression of P53 and dynamin-related protein-1(Drp1)by Western blot analysis and immunofluorescence.AST led to increase of body weight in rats with DM.AST+DM group showed a significant decrease in blood glucose level at week 4 compared with DM group(P<0.05).AST improved renal function and significantly reduced expression of P53 and Drp1 in DM rats.In addition,AST can effectively reduce the blood glucose in DM rats,and delayed the pathogenesis of diabetic nephropathy.Such delay mediated by AST may be associated with the downregulation of Drp1 and P53.展开更多
Astaxanthin(3,3′-dihydroxy-β,β-carotene-4,4′-dione)is an orange-red,lipophilic keto-carotenoid pigment.It is majorly found in marine ecosystems particularly in aquatic animals such as salmon,shrimp,trout,krill,cra...Astaxanthin(3,3′-dihydroxy-β,β-carotene-4,4′-dione)is an orange-red,lipophilic keto-carotenoid pigment.It is majorly found in marine ecosystems particularly in aquatic animals such as salmon,shrimp,trout,krill,crayfish,and so on.It is also synthesized in microalgae Heamatococcus pluvialis,Chlorococcum,Chlorella zofingiensis,red yeast Phaffia rhodozyma and bacterium Paracoccus carotinifaciens.Some aquatic and terrestrial creatures regarded as a primary and secondary sources of the astaxanthin producing and accumulating it through their metabolic pathways.Astax-anthin is the powerful antioxidant,nutritional supplement as well as promising therapeutic compound,observed to have activities against different ravaging diseases and disorders.Researchers have reported remarkable bioactivities of astaxanthin against major non-communicable chronic diseases such as cardiovascular diseases,cancer,diabetes,neurodegenerative,and immune disorders.The current review discusses some structural aspects of astaxanthin.It fur-ther elaborates its multiple potencies such as antioxidant,anti-inflammatory,anti-proliferative,anti-cancer,anti-obese,anti-diabetic,anti-ageing,anti-TB,anti-viral,anti-COVID 19,neuro-protective,nephro-protective,and fertility-enhanc-ing properties.These potencies make it a more precious entity in the preventions as well as treatments of prevalent systematic diseases and/or disorders.Also,the review is acknowledging and documenting its powerful bioactivities in relation with the pharmaceutical as well as nutraceutical applicability.展开更多
Purpose: This research evaluates the efficacy of astaxanthin (AX) on cerebral ischemia/reperfusion (I/R) injury in rats and elucidates the potential mechanism of its neuronal protective effect. Methods: Rats were subj...Purpose: This research evaluates the efficacy of astaxanthin (AX) on cerebral ischemia/reperfusion (I/R) injury in rats and elucidates the potential mechanism of its neuronal protective effect. Methods: Rats were subjected to a middle cerebral artery occlusion/reperfusion (MCAO/R) model. Fifty grown male Sprague-Dawley (SD) rats were divided into 5 groups, including sham operation group (Sham), MCAO/R group, MCAO/R+AX group, MCAO/R+ AX+ Scramble group and MCAO/R+AX+ si-PPAR-γ group. The neurological score and cerebral infarction volume were evaluated after surgery. Rat microglia (RM) were stimulated by lipopolysaccharide (LPS) to form an inflammatory environment. LPS-induced RM cells were incubated with different concentrations of AX (1, 5 or 10 μg/mL), then cell viability, the expression of microglial activation markers, including cytokines (IL-1β, IL-6 and TNF-α), cluster of differentiation 68 (CD68), inducible nitric oxide synthase (iNOS) and CD206 and the expression of PPAR-γ and phosphorylated P65 (p-P65) proteins were determined. Cells were treated with pcDNA-PPAR-γ, as well as treatment with si-PPAR-γ or PPAR-γ antagonist GW9662 before AX treatment, and then cell activation mediators were tested. Results: AX inhibits LPS-induced RM cells activation and enhanced the expression level of PPAR-γ protein in way of dose-dependent, and pcDNA-PPAR-γ treatment had the same effect as AX. While si-PPAR-γ transfection or PPAR-γ suppressant GW9662 treatment reversed the effect of AX, and cut down the level of PPAR-γ protein and augmented the level of p-P65 protein. In addition, AX treatment alleviated the infarct volume, and sensorimotor and cognitive functions of MCAO/R model rats. Conclusion: AX alleviates LPS-induced microglial injury and has a protective effect on rat cerebral I/R injury by regulating the PPAR-γ/NF-κB pathway.展开更多
In recent years,the immune-modulatory role of all-trans astaxanthin from different pigment sources has been studied.It was reported that all-trans astaxanthin might exist as three stereoisomers,and the composition of ...In recent years,the immune-modulatory role of all-trans astaxanthin from different pigment sources has been studied.It was reported that all-trans astaxanthin might exist as three stereoisomers,and the composition of all-trans stereoisomers in natural materials differs from that of synthetic products.However,the different biological effects of various all-trans stereoisomers still remain unclear.In the present study,we evaluated the bioactivity of three astaxanthin stereoisomers,(3S,3'S)-trans-,(3R,3'R)-transand meso-trans-astaxanthin,in regulating cell-mediated immune response using mice lymphocytes and peritoneal exudates cells(PECs) systems.After the treatment with three astaxanthin stereoisomers(20 μmol L-1),the lymphocyte proliferation capacity,neutral red phagocytosis of PECs and natural killer(NK) cell cytotoxic activity were comparatively assessed.The results showed that all three astaxanthin stereoisomers significantly promoted lymphocyte proliferation,phagocytic capacity of PECs,and cytotoxic activity of NK cells.Moreover,the(3S,3'S)-trans-astaxanthin exhibited a much higher response than others.展开更多
Optimization of a process for extracting astaxanthin from Phaffia rhodozyma by acidic method was investigated,regarding several extraction factors such as acids,organic solvents,temperature and time. Fractional factor...Optimization of a process for extracting astaxanthin from Phaffia rhodozyma by acidic method was investigated,regarding several extraction factors such as acids,organic solvents,temperature and time. Fractional factorial design,central composite design and response surface methodology were used to derive a statistically optimal model,which corresponded to the following optimal condition: concentration of lactic acid at 5.55 mol/L,ratio of ethanol to yeast dry weight at 20.25 ml/g,tem-perature for cell-disruption at 30 °C,and extraction time for 3 min. Under this condition,astaxanthin and the total carotenoids could be extracted in amounts of 1294.7 μg/g and 1516.0 μg/g,respectively. This acidic method has advantages such as high extraction efficiency,low chemical toxicity and no special requirement of instruments. Therefore,it might be a more feasible and practical method for industrial practice.展开更多
Euphausia pacific is an important source of natural astaxanthin.Studies were carried out to assess the extractability of astaxanthin from E.pacific using subcritical 1,1,1,2-tetrafluoroethane(R134a).To examine the eff...Euphausia pacific is an important source of natural astaxanthin.Studies were carried out to assess the extractability of astaxanthin from E.pacific using subcritical 1,1,1,2-tetrafluoroethane(R134a).To examine the effects of multiple process variables on the extraction yield,astaxanthin was extracted under various conditions of pressure(30-150 bar),temperature(303-343 K),time(10-50 min),flow rate(2-10 g min-1),moisture content(5.5%-63.61%),and particle size(0.25-0.109 mm).The results showed that the extraction yield increased with temperature,pressure,time and flow rate,but decreased with moisture content and particle size.A maximum yield of 87.74% was obtained under conditions of 100 bar,333 K,and 30 min with a flow rate of 6 g min-1 and a moisture content of 5.5%.The substantial astaxanthin yield obtained under low-pressure conditions demonstrates that subcritical R134a is a good alternative to CO 2 for extraction of astaxanthin from E.pacific.展开更多
The influence of alkali on astaxanthin and the optimal working wave length for measurement of astaxanthin from Haematococcus crude extract were investigated, and a spectrophotometric method for precise quantification ...The influence of alkali on astaxanthin and the optimal working wave length for measurement of astaxanthin from Haematococcus crude extract were investigated, and a spectrophotometric method for precise quantification of the astaxanthin based on the method of Boussiba et al. was established. According to Boussiba's method, alkali treatment destroys chlorophyll. However, we found that: 1) carotenoid content declined for about 25% in Haematococcus fresh cysts and up to 30% in dry powder of Haematococcus broken cysts after alkali treatment; and 2) dimethyl sulfoxide (DMSO)-extracted chlorophyll of green Haematococcus bares little absorption at 520-550 nm. Interestingly, a good linear relationship existed between absorbance at 530 nm and astaxanthin content, while an unknown interference at 540-550 nm was detected in our study. Therefore, with 530 nm as working wavelength, the alkali treatment to destroy chlorophyll was not necessary and the influence of chlorophyll, other carotenoids, and the unknown interference could be avoided. The astaxanthin contents of two samples were measured at 492 nm and 530 nm; the measured values at 530 nm were 2.617 g/100 g and 1.811 g/100 g. When compared with the measured values at 492 nm, the measured values at 530 nm decreased by 6.93% and 11.96%, respectively. The measured values at 530 nm are closer to the true astaxanthin contents in the samples. The data show that 530 nm is the most suitable wave length for spectrophotometric determination to the astaxanthin in Haematococcus crude extract.展开更多
Fermentation of Phaffia rhodozyma is a major method for producing astaxanthin, an important pigment with industrial and pharmaceutical application. To improve astaxanthin productivity, single factor and mixture design...Fermentation of Phaffia rhodozyma is a major method for producing astaxanthin, an important pigment with industrial and pharmaceutical application. To improve astaxanthin productivity, single factor and mixture design experiments were used to investigate the effects of nitrogen source on Phaffia rhodozyma cultivation and astaxanthin production. Results of single factor experiments showed nitrogen source could significantly affect P. rhodozyma cultivation with respect to carbon source utilization, yeast growth and astaxanthin accumulation. Further studies of mixture design experiments using (NH4)2SO4, KNO3 and beef extract as nitrogen sources indicated that the proportion of three nitrogen sources was very important to astaxanthin production. Validation experiments showed that the optimal nitrogen source was composed of 0.28 g/L (NH4)2SO4, 0.49 g/L KNO3 and 1.19 g/L beef extract. The kinetic characteristics of batch cultivation were investigated in a 5-L pH-stat fermentor. The maximum amount of biomass and highest astaxanthin yield in terms of volume and in terms of biomass were 7.71 mg/L and 1.00 mg/g, respectively.展开更多
基金Supported by the Tianjin Excellent Science and Technology Commissioners Project (No.22ZYCGSN00010)the Open Fund of Tianjin Key Laboratory of Aquatic Ecology and Aquaculture (No.TJAE201805)+1 种基金the Open Fund of Key Laboratory of Marine Ecosystem Dynamics (No.MED202013)the Tianjin Natural Science Foundation Project (No.18JCQNJC14800)。
文摘Variation in metabolite profiles of Haematococcus pluvialis(a type of unicellular green algal)under light stress is a key issue of study at the present.To investigate the effect of light intensity on accumulation of astaxanthin in H.pluvialis,a 26-day batch culture experiment of H.pluvialis under the light intensity levels at 73,127,182,236,and 291μmol/(m^(2)·s)was conducted.Therefore,the optimal light intensity and the corresponding metabolic pathways of accumulation in H.pluvialis were determined.Results show that 236μmol/(m^(2)·s)was the optimum light intensity to induce astaxanthin accumulation,at which a maximum content of 9.01 mg/L was achieved on Day 24.A total of 132 metabolites were identified and quantified,of which 38 differential metabolites were highlighted and classified,including 3 fatty acids or intermediates,5 amino acids or derivatives,5 carbohydrates or intermediates,16nucleoside derivatives,and 9 other metabolites using LC-MS/MS technique.Subsequently,16 statistically significant differential metabolic pathways were enriched and annotated based on Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis between the control and the 236μmol/(m^(2)·s)treatment group(P<0.05).In addition,the bioprocesses included cellular basal metabolism and signaling systems,such as carbohydrate metabolism,amino acid metabolism,glycerol and derivatives metabolism,nucleotide and derivative metabolism,and inositol phosphate metabolism were activated and regulated under strong light stress conditions.Moreover,4 hub metabolites containing D-glucose-6-phosphate,L-tyrosine,glycerol-3-phosphate,and L-glutamine were identified,based on which the associated metabolic network was constructed.The study provided a metabolomic view of astaxanthin accumulation in H.pluvialis under strong light stress.
基金The work was supported by the National Key R&D Program of China(No.2018YFD0901103)the National Natural Science Foundation of China(Nos.31901688 and 31571864)+1 种基金the Natural Science Youth Foundation of Shandong Province(Nos.ZR2019QC004 and ZR2020QC236)the Laboratory for Marine Drugs and Bioproducts of Pilot National Laboratory for Marine Science and Technology(Qingdao,No.LMDBKF201807).
文摘Docosahexaenoic acid-acylated astaxanthin(DHA-AST)esters exhibit distinct bioactivities in improving brain function.However,the digestion and absorption characteristics of DHA-AST esters in vivo are unclear,thereby restricting the molecular mechanism analysis of their superior activities.This study compared the digestion and absorption characteristics of DHA-AST monoester and diester by determining the levels of AST and DHA in the serum,liver,small intestinal content and wall,and feces at different time points after a single-dose oral administration of the esters.After oral gavage with 2 mg AST equivalent of the DHA-AST monoester and diester for 18 h,the excretion rates were approximately 51%and 84%,respectively.This result indicates that DHA-AST monoester was better than diester for the absorption of AST.The results in serum,liver,and small intestinal content and wall also agreed with this finding.Moreover,the excretion rates of DHA in the feces at 24 h in the DHA-AST monoester and diester groups were approximately 40%and 36%after gavage with 5 mg DHA equivalent,respectively.This result indicates that DHA-AST diester exhibited a better tendency than monoester for the absorption of DHA.Interestingly,the results in the liver and small intestinal wall showed an apparent difference,indicating that DHA-AST diester was better than monoester for the absorption of DHA.These findings provide a scientific basis for the molecular mechanism analysis and utilization of DHA-AST monoester and diester as functional ingredients.
基金Supported by the National Natural Science Foundation of China(No.31572638)the Public Benefit Program of Zhejiang Science and Technology Department(No.2015C32021)+4 种基金the Program of Ningbo Science and Technology Bureau(No.2014C10023)the NSF of Ningbo Government(No.2015A610265)the Project of Science and Technology Innovation for College Students in Zhejiang Province(No.2016R405078)the K.C.Wong Magna Fund in Ningbo Universitythe Subject Project of Ningbo University(No.xkl1526)
文摘The optimum concentration of Na_2 WO_4 was explored in relation to the cell density and astaxanthin content in Haematococcus pluvialis. Then, the cellular morphology, nitrate reductase(NR) activity, soluble sugar and protein contents, and chlorophyll ?uorescence were measured, and the transcriptional expression of carotenogenic genes was determined by quantitative real-time PCR. The results showed that 3.0 mmol/L of Na_2 WO_4 was the optimum concentration to induce astaxanthin accumulation, with a maximum content of 49.41±0.13 pg/cell reached on the tenth day. The NR activity decreased signi?cantly and continually after Na_2 WO_4 treatment. The soluble sugar content increased gradually during the experimental period and was eventually signi?cantly higher than that in the control. The soluble protein content increased rapidly,reached a maximum in day 0.5 and day 1 and then decreased. The ef fective photochemical effciency of PSII( F v'/F m') and light saturation( E k) ?rst decreased and then tended to stabilize, and NADP +-glyceraldehyde-3-phosphate dehydrogenase(GAPDH) gene expression was correlated with photosynthesis. The transcriptional expression of ipi, psy and bkt was signi?cantly increased compared with that in the control after application of Na_2 WO_4, and the relative expression of ipi reached the highest level on the ?fth day, with a 98.03±1.92-fold increase. Our results describe a new approach to promote the ef fective accumulation of astaxanthin in H. pluvialis by NR inhibitor Na_2 WO_4.
基金Supported by the National Natural Science Foundation of China(No.81870632)Youth Project of Natural Science Foundation of ghandong Province(No.ZR2019BH004).
文摘AIM:To characterize effect of astaxanthin(ASX)in Aspergillus fumigatus(A.fumigatus)induced keratitis in mouse model.METHODS:In vivo,fungal keratitis mouse model was established in C57BL/6 mice using A.fumigatus,followed by ASX or dimethyl sulfoxide(DMSO)treatment.Clinical responses were evaluated by clinical score and myeloperoxidase(MPO)assay.Inflammatory cytokines were assessed by reverse-transcription polymerase chain reaction(RT-PCR),Western blot,immunofluorescence,and enzyme-linked immuno sorbent assay(ELISA).RESULTS:In animal model,ASX improved corneal transparency and clinical response,suppressed the expression of inflammatory cytokine like IL-1β,TNF-α,and HMGB-1.Neutrophil levels have been shown to decrease in ASX-treated cornea by immunofluorescence and MPO.TLR2 and TLR4 levels were lower in ASX-treated group than DMSO-treated.CONCLUSION:ASX can suppress inflammatory response and reduce inflammatory cytokine production in mice model with A.fumigatus keratitis.
基金This study was supported by Modern Agricultural Industry Technology System-Peking Poultry Innovation Team(BAIC04–2021)the National Key R&D Program of China(2016YFD0700201).
文摘Background:Natural astaxanthin(ASTA)has strong antioxidant properties and has been widely used as a health product to improve human health.However,the effects of ASTA on the reproductive performance of aging roosters have been poorly studied.We aimed to investigate the effects of dietary ASTA on semen quality and antioxidant capacity in aging roosters and to explore the potential mechanism of semen quality change via antioxidation defense system.Methods:In the present study,9653-week-old Jinghong No.1 layer breeder roosters were fed a corn-soybean meal basal diet containing 0,25,50,or 100 mg/kg ASTA for 6 weeks.Results:Semen quality in the ASTA groups remarkably improved than that in the control group,and antioxidant activities,the abilities to scavenge hydroxyl radicals and superoxide anions,increased gradually with ASTA addition(P<0.05).In addition,the mRNA levels of antioxidant enzymes as well as the mRNA and protein levels of the mitogen-activated protein kinase(MAPK)and nuclear factor-erythroid 2-related factor 2(Nrf2)were markedly increased in the 50-100 mg/kg ASTA group(P<0.05).Conclusions:Collectively,these results demonstrate that dietary ASTA may improve semen quality by increasing antioxidant enzyme activities and the ability to scavenge hydroxyl radicals,which may be related to upregulation of the MAPK/Nrf2 pathway.
基金This study was supported by a research grant from Department of Economic Plants and Biotechnology,Yunnan Key Laboratory for Wild Plant Resources,Kunming Institute of Botany,Chinese Academy of Sciences.
文摘Astaxanthin is a value-added ketocarotenoid with great potential in nutraceutical and pharmaceutical industries.Genetic engineering of heterologous hosts for astaxanthin production has attracted great attention.In this study,we assessed some key factors,including codon usage of the expressed genes,types of promoters,bacterial strains,and culture media,for engineered Escherichia coli to produce astaxanthin.The effect of codon usage was shown to be related to the types of promoters.E.coli DH5a was superior to other strains for astaxanthin production.Different culture media greatly affected the contents and yields of astaxanthin in engineered E.coli.When the expression cassette containing GadE promoter and its driving genes,HpCHY and CrBKT,was inserted into the plasmid pACCAR16DcrtX and expressed in E.coli DH5a,the engineered strain was able to produce 4.30±0.28 mg/g dry cell weight(DCW)or 24.16±2.03 mg/L of astaxanthin,which was a sevenfold or 40-fold increase over the initial production of 0.62±0.03 mg/g DCW or 0.61±0.05 mg/L.
基金This research was supported by National Natural Science Foundation of China(41806168)Agriculture Research System of China(CARS-50)+2 种基金Start-Up funding of Shantou University(NTF18004)Department of Education of Guangdong Province(2017KQNCX076)International cooperation research project of Shantou University(NC2017001).
文摘Given the central role of light in the algal photosynthesis,respiration,cell division,growth and the accumulation of value products,the effects of light-emitting diodes(LEDs)light wavelengths(blue,white,red and green)were studied in Scenedesmus obliquus.Biomass,residual nutrient amount,soluble protein,astaxanthin and reactive oxygen species,superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)activity were analyzed to determine the effects of different monochromatic light wavelengths via biochemical methods.The results showed that blue light wavelength is the optimal light wavelength for phosphorus removal efficiency and the accumulation of biomass and astaxanthin in S.obliquus.Meanwhile,high reactive oxygen species content under the blue light might induce the accumulation of astaxanthin.The high activity of SOD,CAT and POD might participate in clearing the reactive oxygen species to facilitate the growth of microalgae.Furthermore,we found mixed blue/green lights treatment is the most appropriate mixture for the nitrogen removal.Under the blue light treatment,high light intensity and 18L:6D light cycle is the best condition for biomass and astaxanthin accumulation.Optimal nitrogen/phosphorus removal efficiency was observed under a 24L:0D light cycle.These results might provide a foundational data for the optimizing the productivity of high-value metabolites and treatment of wastewater.
文摘AIM: To observe the protective effect of astaxanthin(AST) against hydroquinone(HQ) mediated cell death in the apoptotic cascade and evaluate intracellular Ca2+ release, caspase-3, and-9 activation, reactive oxygen species(ROS) production in ARPE-19 cells.METHODS: We cultured ARPE-19 cells in special mediums and performed MTT tests to determine protective effect of AST, before exposing the cells to HQ in an incubator. We analyzed intracellular Ca2+ release experiments, mitochondrial membrane depolarization, glutathione(GSH), glutathione peroxidase(GSH-Px) and ROS experiments, and apoptosis assay.RESULTS: ROS production ranges depend on the amount of cell death. We computed the correlation between ROS ranges and cell death by 20,70-dichlorofluorescein fluorescence, and Ca2+ levels by Fura-2-AM. HQ-induced cell death found out to rise ranges of caspase-3 and-9, and mitochondrial depolarization. These three steps were delayed by AST management.CONCLUSION: ARPE-19 cells are avoided from HQinduced ROS production and caspase-3 and-9 activation by AST. AST may limit the range of caspase synthesis, Ca2+ release and excess production of ROS with antiapoptotic effect. This study proposes a new therapeutic approach for the treatment of age-related macular degeneration.
文摘Astaxanthin （ATX） , the most abundant flavonoids in propolis, has been proven to exert neuroprotective property against cerebral ischemia-induced apoptosis. However, the mechanisms by which ATX mediates its thera- peutic effects in vitro are unclear. In the present study, the article explored the underlying mechanisms involved in the protective effects of ATX via the PI3IC/Akt/GSK3β/Nrf2 signaling pathway in SH-SY5Y cells. For study of mechanism, the phosphoinositide 3 kinase （PI3K）-Akt inhibitor LY294002, Glycogen synthase kinase 3β （GSK313） inhibitor LiC1 were used. Pre-treatmentwith ATX for 24h significantly reduced the OGD induced viability loss, apoptotic rate and attenuated OGD-mediated ROS production. In addition, ATX inhibited OGD-induced mito- chondrial membrane potential, decreased Bcl-2/Bax ratio. PI3 IC/Akt/GSK3β/Nrf2 signaling pathway activation in SH-SY5Y was tested by Western blot. Nrf2 expression was increasing by ATX and counteracted by PI3IC/Akt in- hibitor LY294002, GSK3β inhibitor LiC1 in SH-SY5Y. Nrf2 Immunocytochemistry showed Nrf2 nuclear transloca- tion was increasing by ATX and counteracted by LY294002 or LiC1 in SH-SY5Y, respectively. It may be suggested that astaxanthin against cerebral ischemia-induced apoptosis in vitro via a programmed PI3 IC/Akt/GSK3β/Nrf2 sig- naling pathway in vitro.
文摘Alzheimer’s Disease is projected to increase to 30 million people in the next 30 years and the rate of diabetes mellitus is projected to rise also. Hyperglycemia is commonly observed in patients with diabetes mellitus, and hypoglycemia is a common consequence due to insulin therapy. Previous research has shown a potential link between Alzheimer’s disease and diabetes. This study sought to determine if Astaxanthin (ATX) could prevent mitochondrial dysfunction from the compounded effects of amyloid β (Aβ) plaque and hypoglycemia or hyperglycemia. Growth patterns, ATP production, and ROS generation were examined in 2 μM, 5 μM, 25 μM (hypoglycemic groups), 2 mM, 5 mM (normal groups), and 25 mM glucose (hyperglycemic group), and then treated with or without ATX or Aβ. When hypoglycemia groups and the hyperglycemia group were treated with ATX, their growth patterns were either comparable to control or increased. ATX and Aβ treated cells demonstrated increased growth patterns over cells treated with Aβ alone. Aβ alone treated groups overall had significantly less growth than controls (p β demonstrated low levels of average fluorescence generated by ROS production as determined by MitoSox assay while ATX groups actually produced higher to normal levels of ROS. Cells grown in the presence of Aβ and ATX generally produced more ROS than just Aβ groups. Thus, hypoglycemia and hyperglycemia do appear to compound the effects of Aβ on hippocampal cells. ATX treatment demonstrated promise with increased cellular growth, which promoted usage of ATP by the cell and ROS production. This growth was present even in the presence of Aβ, suggesting that ATX is able to overcome the negative effects of Aβ.
基金This study was supported by Yantai Science and Technology Plan Project[Grant No.2018ZHGY088].
文摘This study was designed to investigate the protective effects of Astaxanthin(AST)in rats with diabetes mellitus(DM)induced by streptozotocin.SD rats were divided into control group(n=5,only received normal saline),DM group(n=8)and AST+DM group(n=8;AST:50 mg/kg/day).DM rats were induced by intraperitoneal injection of streptozocin(STZ,65 mg/kg).Blood glucose level and body weight were determined at weeks 0,2,4,6 and 8,respectively.At week 8,kidney function was determined,together with expression of P53 and dynamin-related protein-1(Drp1)by Western blot analysis and immunofluorescence.AST led to increase of body weight in rats with DM.AST+DM group showed a significant decrease in blood glucose level at week 4 compared with DM group(P<0.05).AST improved renal function and significantly reduced expression of P53 and Drp1 in DM rats.In addition,AST can effectively reduce the blood glucose in DM rats,and delayed the pathogenesis of diabetic nephropathy.Such delay mediated by AST may be associated with the downregulation of Drp1 and P53.
基金support through the Chief Minister Special Research Fellowship-2019 (CMSRF-2019).
文摘Astaxanthin(3,3′-dihydroxy-β,β-carotene-4,4′-dione)is an orange-red,lipophilic keto-carotenoid pigment.It is majorly found in marine ecosystems particularly in aquatic animals such as salmon,shrimp,trout,krill,crayfish,and so on.It is also synthesized in microalgae Heamatococcus pluvialis,Chlorococcum,Chlorella zofingiensis,red yeast Phaffia rhodozyma and bacterium Paracoccus carotinifaciens.Some aquatic and terrestrial creatures regarded as a primary and secondary sources of the astaxanthin producing and accumulating it through their metabolic pathways.Astax-anthin is the powerful antioxidant,nutritional supplement as well as promising therapeutic compound,observed to have activities against different ravaging diseases and disorders.Researchers have reported remarkable bioactivities of astaxanthin against major non-communicable chronic diseases such as cardiovascular diseases,cancer,diabetes,neurodegenerative,and immune disorders.The current review discusses some structural aspects of astaxanthin.It fur-ther elaborates its multiple potencies such as antioxidant,anti-inflammatory,anti-proliferative,anti-cancer,anti-obese,anti-diabetic,anti-ageing,anti-TB,anti-viral,anti-COVID 19,neuro-protective,nephro-protective,and fertility-enhanc-ing properties.These potencies make it a more precious entity in the preventions as well as treatments of prevalent systematic diseases and/or disorders.Also,the review is acknowledging and documenting its powerful bioactivities in relation with the pharmaceutical as well as nutraceutical applicability.
文摘Purpose: This research evaluates the efficacy of astaxanthin (AX) on cerebral ischemia/reperfusion (I/R) injury in rats and elucidates the potential mechanism of its neuronal protective effect. Methods: Rats were subjected to a middle cerebral artery occlusion/reperfusion (MCAO/R) model. Fifty grown male Sprague-Dawley (SD) rats were divided into 5 groups, including sham operation group (Sham), MCAO/R group, MCAO/R+AX group, MCAO/R+ AX+ Scramble group and MCAO/R+AX+ si-PPAR-γ group. The neurological score and cerebral infarction volume were evaluated after surgery. Rat microglia (RM) were stimulated by lipopolysaccharide (LPS) to form an inflammatory environment. LPS-induced RM cells were incubated with different concentrations of AX (1, 5 or 10 μg/mL), then cell viability, the expression of microglial activation markers, including cytokines (IL-1β, IL-6 and TNF-α), cluster of differentiation 68 (CD68), inducible nitric oxide synthase (iNOS) and CD206 and the expression of PPAR-γ and phosphorylated P65 (p-P65) proteins were determined. Cells were treated with pcDNA-PPAR-γ, as well as treatment with si-PPAR-γ or PPAR-γ antagonist GW9662 before AX treatment, and then cell activation mediators were tested. Results: AX inhibits LPS-induced RM cells activation and enhanced the expression level of PPAR-γ protein in way of dose-dependent, and pcDNA-PPAR-γ treatment had the same effect as AX. While si-PPAR-γ transfection or PPAR-γ suppressant GW9662 treatment reversed the effect of AX, and cut down the level of PPAR-γ protein and augmented the level of p-P65 protein. In addition, AX treatment alleviated the infarct volume, and sensorimotor and cognitive functions of MCAO/R model rats. Conclusion: AX alleviates LPS-induced microglial injury and has a protective effect on rat cerebral I/R injury by regulating the PPAR-γ/NF-κB pathway.
基金supported by Program for Changjiang Scholars and Innovative Research Team in University (IRT1188)
文摘In recent years,the immune-modulatory role of all-trans astaxanthin from different pigment sources has been studied.It was reported that all-trans astaxanthin might exist as three stereoisomers,and the composition of all-trans stereoisomers in natural materials differs from that of synthetic products.However,the different biological effects of various all-trans stereoisomers still remain unclear.In the present study,we evaluated the bioactivity of three astaxanthin stereoisomers,(3S,3'S)-trans-,(3R,3'R)-transand meso-trans-astaxanthin,in regulating cell-mediated immune response using mice lymphocytes and peritoneal exudates cells(PECs) systems.After the treatment with three astaxanthin stereoisomers(20 μmol L-1),the lymphocyte proliferation capacity,neutral red phagocytosis of PECs and natural killer(NK) cell cytotoxic activity were comparatively assessed.The results showed that all three astaxanthin stereoisomers significantly promoted lymphocyte proliferation,phagocytic capacity of PECs,and cytotoxic activity of NK cells.Moreover,the(3S,3'S)-trans-astaxanthin exhibited a much higher response than others.
基金Project supported by the National Natural Science Foundation of China (No. 20702019)the Foundation for Young Professors of Jimei University, China
文摘Optimization of a process for extracting astaxanthin from Phaffia rhodozyma by acidic method was investigated,regarding several extraction factors such as acids,organic solvents,temperature and time. Fractional factorial design,central composite design and response surface methodology were used to derive a statistically optimal model,which corresponded to the following optimal condition: concentration of lactic acid at 5.55 mol/L,ratio of ethanol to yeast dry weight at 20.25 ml/g,tem-perature for cell-disruption at 30 °C,and extraction time for 3 min. Under this condition,astaxanthin and the total carotenoids could be extracted in amounts of 1294.7 μg/g and 1516.0 μg/g,respectively. This acidic method has advantages such as high extraction efficiency,low chemical toxicity and no special requirement of instruments. Therefore,it might be a more feasible and practical method for industrial practice.
基金Supported by the Fundamental Research Funds for the Central Universities （FRF-AS-10-001B） and the National Natural Science Foundation of China （11071013）.
基金supported by the National Natural Science Foundation of China (No.31071541)
文摘Euphausia pacific is an important source of natural astaxanthin.Studies were carried out to assess the extractability of astaxanthin from E.pacific using subcritical 1,1,1,2-tetrafluoroethane(R134a).To examine the effects of multiple process variables on the extraction yield,astaxanthin was extracted under various conditions of pressure(30-150 bar),temperature(303-343 K),time(10-50 min),flow rate(2-10 g min-1),moisture content(5.5%-63.61%),and particle size(0.25-0.109 mm).The results showed that the extraction yield increased with temperature,pressure,time and flow rate,but decreased with moisture content and particle size.A maximum yield of 87.74% was obtained under conditions of 100 bar,333 K,and 30 min with a flow rate of 6 g min-1 and a moisture content of 5.5%.The substantial astaxanthin yield obtained under low-pressure conditions demonstrates that subcritical R134a is a good alternative to CO 2 for extraction of astaxanthin from E.pacific.
基金Supported by the Yunnan Provincial Sciences and Technology Department,China (No. 2007AD009)the National Natural Science Foundation of China (No. CNSF30570183)the Knowledge Innovation Program of Chinese Academy of Sciences (No. KSCX2-YW-G-060)
文摘The influence of alkali on astaxanthin and the optimal working wave length for measurement of astaxanthin from Haematococcus crude extract were investigated, and a spectrophotometric method for precise quantification of the astaxanthin based on the method of Boussiba et al. was established. According to Boussiba's method, alkali treatment destroys chlorophyll. However, we found that: 1) carotenoid content declined for about 25% in Haematococcus fresh cysts and up to 30% in dry powder of Haematococcus broken cysts after alkali treatment; and 2) dimethyl sulfoxide (DMSO)-extracted chlorophyll of green Haematococcus bares little absorption at 520-550 nm. Interestingly, a good linear relationship existed between absorbance at 530 nm and astaxanthin content, while an unknown interference at 540-550 nm was detected in our study. Therefore, with 530 nm as working wavelength, the alkali treatment to destroy chlorophyll was not necessary and the influence of chlorophyll, other carotenoids, and the unknown interference could be avoided. The astaxanthin contents of two samples were measured at 492 nm and 530 nm; the measured values at 530 nm were 2.617 g/100 g and 1.811 g/100 g. When compared with the measured values at 492 nm, the measured values at 530 nm decreased by 6.93% and 11.96%, respectively. The measured values at 530 nm are closer to the true astaxanthin contents in the samples. The data show that 530 nm is the most suitable wave length for spectrophotometric determination to the astaxanthin in Haematococcus crude extract.
基金Project supported by the National Natural Science Foundation of China (No.30571450)the Foundation for Young Professors of Jimei University of Xiamen,China
文摘Fermentation of Phaffia rhodozyma is a major method for producing astaxanthin, an important pigment with industrial and pharmaceutical application. To improve astaxanthin productivity, single factor and mixture design experiments were used to investigate the effects of nitrogen source on Phaffia rhodozyma cultivation and astaxanthin production. Results of single factor experiments showed nitrogen source could significantly affect P. rhodozyma cultivation with respect to carbon source utilization, yeast growth and astaxanthin accumulation. Further studies of mixture design experiments using (NH4)2SO4, KNO3 and beef extract as nitrogen sources indicated that the proportion of three nitrogen sources was very important to astaxanthin production. Validation experiments showed that the optimal nitrogen source was composed of 0.28 g/L (NH4)2SO4, 0.49 g/L KNO3 and 1.19 g/L beef extract. The kinetic characteristics of batch cultivation were investigated in a 5-L pH-stat fermentor. The maximum amount of biomass and highest astaxanthin yield in terms of volume and in terms of biomass were 7.71 mg/L and 1.00 mg/g, respectively.
