Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological proce...Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.展开更多
Background:SMAD family proteins(SMADs)are crucial transcription factors downstream of transforming growth factor beta(TGF-ß)/SMAD signaling pathways that have been reported to play a pivotal role in mammalian rep...Background:SMAD family proteins(SMADs)are crucial transcription factors downstream of transforming growth factor beta(TGF-ß)/SMAD signaling pathways that have been reported to play a pivotal role in mammalian reproduction.However,the role of SMAD family member 8(SMAD8,also known as SMAD9),a member of the SMAD family,in mammalian reproduction remains unclear.Methods:We employed RNA interference techniques to knock down Smad8 expression in mouse granulosa cells(GCs)to investigate the effects of Smad8 on GC growth and steroidogenesis.Results:Our findings revealed a significant decrease in the proliferative capacity and a substantial increase in the apoptosis rate of GCs after transfection with Smad8-siRNA for 48 h.Subsequent hormone assays demonstrated a significant decrease in estradiol(E2)levels,whereas progesterone(P4)remained unchanged.Further mechanistic analysis showed that the mRNA expression of proliferating cell nuclear antigen(Pcna),Cyclin D2,cell cycle-dependent kinase 4(Cdk4),B-cell lymphoma-2(Bcl-2),estrogen receptor(Er),luteinizing hormone receptor(Lhr)and cytochrome P450 family 19 subfamily A member 1(Cyp19a1)significantly decreased.Conversely,the mRNA of cysteine aspartate proteinase 3(Caspase 3)significantly increased,wheras Bcl2-associated X(Bax),folliclestimulating hormone receptor(Fshr)and cytochrome P450 family 11 subfamily A member 1(Cyp11a1)remained unchanged compared to the controls.Conclusion:This study indicates that Smad8 knockdown inhibits cell proliferation,promotes apoptosis,reduces Er and Lhr transcription,and decreases E2 production in mouse GCs.These findings suggest that Smad8 may serve as a novel genetic marker for mammalian reproduction.展开更多
Using N-methyl-D-glucosamine(NMDG)as the functional monomer,glycidyl methacrylate(GMA)as the connecting monomer,functionalized Fe3O4 nano-particles(NPs)as the support,three adsorbents were prepared including direct po...Using N-methyl-D-glucosamine(NMDG)as the functional monomer,glycidyl methacrylate(GMA)as the connecting monomer,functionalized Fe3O4 nano-particles(NPs)as the support,three adsorbents were prepared including direct polymer GMA-NMDG,magnetic GMA-NMDG polymer(MGN),and boron magnetic ion-imprinted polymer(BMIIP).Based upon the optimization of synthesis conditions,the prepared adsorbents and intermediate products were characterized using Fourier transform infrared spectroscopy,thermogravimetric analysis,scanning electron microscope,energy dispersive spectroscopy,X-ray diffraction,vibrating sample magnetometer,and Brunauer–Emmett–Teller to investigate the synthesis process,the morphological structure and the functional properties of the materials.The optimum performances of GMA-NMDG,MGN and BMIIP were obtained in the initial neutral solution(pH of 6.5).Moreover,GMANMDG and MGN reached the maximum adsorption capacity at 120 min,whereas BMIIP reached adsorption saturation at 60 min.The pseudo-second-order kinetic model was more suitable for the adsorption of boron using the adsorbents.The maximum adsorption capacity of GMA-NMDG was found to be 43.4 mg·g^(-1),while those of MGN and BMIIP were 32.5 and 28.3 mg·g^(-1),respectively.The Langmuir isotherm model was more appropriate to describe the adsorption process.The adsorbents maintained satisfactory adsorption performance within a certain temperature range.Competing ions had little effect on the adsorption of boron,and would be adsorbed simultaneously,due to which,the effect of co-adsorption can be considered.The adsorption capacity of GMA-NMDG was high,while the adsorption selectivity of BMIIP was much better.Furthermore,BMIIP showed good adsorption after five cycles of adsorption and desorption.The comparison of adsorbents showed that GMA-NMDG had the highest adsorption capacity and was suitable for co-adsorption.MGN had a high adsorption capacity,good comprehensive performance and magnetic properties.BMIIP had better adsorption rate,adsorption selectivity and recyclability.Through the optimization of synthesis conditions,the adsorption capacity of the traditional monomer NMDG polymer was increased,and the magnetism was given to facilitate rapid recovery.Combined with the ion imprinting technology,it showed higher boron adsorption selectivity in the presence of competitive ions.展开更多
Adenylate cyclase(AC)is the key enzyme that catalyzes the formation of cAMP from ATP.In this study,we discovered two novel class Ⅲ ACs with a halophilic property from Thermobifida halotolerans DSM 44931(ThAC)and Halo...Adenylate cyclase(AC)is the key enzyme that catalyzes the formation of cAMP from ATP.In this study,we discovered two novel class Ⅲ ACs with a halophilic property from Thermobifida halotolerans DSM 44931(ThAC)and Haloactinopolyspora alba DSM 45211(HaAC),respectively.The recombinant ThAC and HaAC were expressed in Escherichia coli with molecular weights of 36.1 and 36.0 kDa respectively.The presence of 2500 and 2200 mmolL^(-1)1 NaCl significantly enhanced the enzyme activities of ThAC and HaAC,with 22-fold and 7.4-fold higher activities compared to those without NaCl,respectively.Several divalent metal ions were found to activate the recombinant ACs to different extents,and the optimal metal ion was Mg^(2+)for both ThAC and HaAC with concentrations of 80 mmol·L^(-1) and 40 mmol·L^(-1) respectively.Purified ThAC and HaAC had the optimal specific activities((4.59±0.35)×10^(4) and(7.76±0.52)×10^(4) U·mg^(-1))and catalytic efficiency(4.47 and 5.30 L·mmol^(-1)·s^(-1))at 45℃ and 40℃ respectively,while the optimum pH of both two recombinant ACs was 10.0.This is the first report of the halophilic Class III ACs,which could make new contributions to explore and study ACs for further associated investigations.展开更多
Due to the scale effect, the uniform distribution of reagents in continuous flow reactor becomes bad when the channel is enlarged to tens of millimeters. Microfluidic field strategy was proposed to produce high mixing...Due to the scale effect, the uniform distribution of reagents in continuous flow reactor becomes bad when the channel is enlarged to tens of millimeters. Microfluidic field strategy was proposed to produce high mixing efficiency in large-scale channel. A 3D spiral baffle structure(3SBS) was designed and optimized to form microfluidic field disturbed by continuous secondary flow in millimeter scale Y-shaped tube mixer(YSTM). Enhancement effect of the 3SBS in liquid-liquid homogeneous chemical processes was verified and evaluated through the combination of simulation and experiment. Compared with 1 mm YSTM, 10 mm YSTM with 3SBS increased the treatment capacity by 100 times, shortened the basic complete mixing time by 0.85 times, which proves the potential of microfluidic field strategy in enhancement and scale-up of liquid-liquid homogeneous chemical process.展开更多
Magnetically modified palygorskite composites were synthesized with γ-Fe2O3 dispersing on the external surface of clay mineral. The magnetic clay was characterized with Fourier transform infrared, X-ray diffraction, ...Magnetically modified palygorskite composites were synthesized with γ-Fe2O3 dispersing on the external surface of clay mineral. The magnetic clay was characterized with Fourier transform infrared, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. Candida sp. 99–125 lipase was immobilized on magnetic palygorskite composites by physical adsorption with enzyme loading of41.5 mg·g-1support and enzyme activity of 2631.6 U·(g support)-1. The immobilized lipase exhibit better thermal and broader p H stability and excellent reusability compared with free lipase.展开更多
Bio-based diamines are considered to be a promising alternative to traditional fossil-fuel-based diamines,the important platform chemical for the synthesis of polymer materials.In this review,the current status of the...Bio-based diamines are considered to be a promising alternative to traditional fossil-fuel-based diamines,the important platform chemical for the synthesis of polymer materials.In this review,the current status of the art of the synthesis of aliphatic and aromatic diamines from renewable biomass are considered.In the case of aliphatic diamines,we describe strategies for biologically producing diamines with different carbon numbers including 1,3-diaminopropane,1,4-butanediamine,1,5-pentanediamine,1,6-diaminohexane,1,8-diaminooctane,1,10-diaminodecane,and 1,12-diaminododecane.In addition,aromatic diamines produced from various kinds of renewable biomass,including lignin,cashew nut shell,and terpenoids,are reviewed here.Furthermore,the application of typical diamines in synthesis of polyurethane and polyamide are also reviewed.展开更多
Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of biocatalysis.These chemoenzymatic methods can not only sav...Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of biocatalysis.These chemoenzymatic methods can not only save resource,cost,and operating time but also reduce the number of reaction steps,and avoid separating unstable intermediates,leading to the generation of more products under greener circumstances and thereby playing an indispensable role in the fields of medicine,materials and fine chemicals.Although incompatible challenges between chemocatalyst and biocatalyst remain,strategies such as biphasic system,artificial metalloenzymes,immobilization or supramolecular host,and protein engineering have been designed to overcome these issues.In this review,chemoenzymatic catalysis according to different chemocatalysis types was classifiably described,and in particular,the classic dynamic kinetic resolutions(DKR)and cofactor regeneration were summarized.Finally,the bottlenecks and development of chemoenzymatic catalysis were summarized,and future development was prospected.展开更多
Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. I...Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU). Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B. subtilis Bac01 and mutant strain Bac11. BLAST comparison result indicated that 10 nucleotides mutated. Bioinformatics methods were used to analyze the two predicted amino acid sequences, and it was found that 5 amino acid residues changed, being all in the cellulose-binding domain of endoglucanase.展开更多
A novel benzisothiazolin-3-one derivative, 2-(benzo[d]isothiazol-3-yloxy)-N-(3-cyano-1-(4-fluorophenyl)-1H-pyrazol-5-yl) acetamide(8), was synthesized from the initial compound benzo[d]isothiazol-3(2H)-one(BIT) 1 and ...A novel benzisothiazolin-3-one derivative, 2-(benzo[d]isothiazol-3-yloxy)-N-(3-cyano-1-(4-fluorophenyl)-1H-pyrazol-5-yl) acetamide(8), was synthesized from the initial compound benzo[d]isothiazol-3(2H)-one(BIT) 1 and 4-fluoroaniline 3. The structure of the target compound 8 was determined by elemental analyses, IR and 1H NMR. The single crystals of intermediate compound 6 and the target compound 8 were obtained and determined by X-ray diffraction analysis. The preliminary biological activity was also evaluated and the results showed the target compound exhibited a good anti-microbial activity.展开更多
Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the th...Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.展开更多
The crystal structure of the title compound(Z)-5-fluoro-3-(phenyl((5-(pyridin-3-ylmethyl)thiophen-2-yl)amino)methylene)indolin-2-one(C_(25)H_(18)FN_3OS,M_r=427.50)has been prepared and determined by single-crystal X-r...The crystal structure of the title compound(Z)-5-fluoro-3-(phenyl((5-(pyridin-3-ylmethyl)thiophen-2-yl)amino)methylene)indolin-2-one(C_(25)H_(18)FN_3OS,M_r=427.50)has been prepared and determined by single-crystal X-ray diffraction.The crystal is of orthorhombic,space group P2_12_12_1 with a=5.931(1),b=12.413(1),c=28.102(2)A,V=2090.4(3)A^3,Z=4,D_c=1.358 g/cm^3,F(000)=888,μ=0.186 mm^(-1),MoKa radiation(λ=0.71073),R=0.041 and wR=0.105 for 4567 observed reflections with I>2σ(I).X-ray diffraction analysis reveals that the indole and thiophene rings are not coplanar with a dihedral angle of 46.26(5)°.Intramolecular and intermolecular N-H…O hydrogen bonds together with C-H…πinterations can be observed in the lattice.展开更多
Exopolysaccharides can be produced by various bacteria and have important biological roles in bacterial survival depend on molecular weight,linkage,and conformation.In this study,Leuconostoc pseudomesenteroides G29 wa...Exopolysaccharides can be produced by various bacteria and have important biological roles in bacterial survival depend on molecular weight,linkage,and conformation.In this study,Leuconostoc pseudomesenteroides G29 was identified and found to produce two types of exopolysaccharides from sucrose including soluble and insoluble a-glucans.By regulation of pH above 5.5,soluble a-glucan production was increased to 38.4 g∙L^(-1) from 101.4 g∙L^(-1) sucrose with fewer accumulation of lactic acid and acetic acid.Simultaneously,the quantity of thick white precipitate,that is insoluble a-glucan,was also increased.Then,a-glucans were prepared by enzymatic reaction with crude glucansucrases from the supernatant of G29 fermentation broth and purified for structure analysis.Based on the integration analysis of FT-IR and NMR,it was observed that soluble a-glucan is a highly linear dextran with α-1,6 glycosidic bonds while the insoluble a-glucan has 93%of α-1,3 and 7%of α-1,6 glycosidic bond.The results extend our understanding of exopolysaccharides production by L.pseudomesenteroides,and this water insoluble α-1,3-glucan might have potential application as biomaterials and/or biochemicals.展开更多
Compared with conventional cylinder airlift bioreactors(CCABs)that produce coarse bubbles,a novel rectangular dynamic membrane airlift bioreactor(RDMAB)developed in our lab produces fine bubbles to enhance the volumet...Compared with conventional cylinder airlift bioreactors(CCABs)that produce coarse bubbles,a novel rectangular dynamic membrane airlift bioreactor(RDMAB)developed in our lab produces fine bubbles to enhance the volumetric oxygen mass transfer coefficient(k_(L)a)and gas holdup,as well as improve the bioprocess in a bioreactor.In this study,we compared mass transfer,gas holdup,and batch and con-tinuous fermentation for RNA production in CCAB and RDMAB.In addition,unstructured kinetic models for microbial growth,substrate utilization,and RNA formation were established.In batch fermentation,biomass,RNA yield,and substrate utilization in the RDMAB were higher than those in the CCAB,which indicates that dynamic membrane aeration produced a high k_(L)a by fine bubbles;a higher k_(L)a is more bene-ficial to aerobic fermentation.The starting time of continuous fermentation in the RDMAB was 20 h ear-lier than that in the CCAB,which greatly improved the biological process.During continuous fermentation,maintaining the same dissolved oxygen level and a constant dilution rate,the biomass accumulation and RNA concentration in the RDMAB were 9.71% and 11.15% higher than those in the CCAB,respectively.Finally,the dilution rate of RDMAB was 16.7% higher than that of CCAB during con-tinuous fermentation while maintaining the same air aeration.In summary,RDMAB is more suitable for continuous fermentation processes.Developing new aeration and structural geometry in airlift bioreac-tors to enhance k_(L)a and gas holdup is becoming increasingly important to improve bioprocesses in a bioreactor.展开更多
The title compound(S)-N-(hexahydro-2-oxo-1H-azepin-3-yl)-3-phenyl-2-propenamide(C15H18N2O2, Mr = 258.31) was synthesized by the reaction of(S)-α-amino-ε-caprolactam with 3-phenyl-2- propenoyl chloride. Its chemical ...The title compound(S)-N-(hexahydro-2-oxo-1H-azepin-3-yl)-3-phenyl-2-propenamide(C15H18N2O2, Mr = 258.31) was synthesized by the reaction of(S)-α-amino-ε-caprolactam with 3-phenyl-2- propenoyl chloride. Its chemical structure was determined by 1H NMR, 13C NMR, H RMS and X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 14.957(3), b = 4.884(1), c = 18.630(4), β = 95.91(3)o, V = 1353.7(5)3, Z = 4, Dc = 1.267 g/cm3, μ = 0.085 mm-1, F(000) = 552, R = 0.0671 and wR = 0.1547 for 2473 observed reflections with I > 2σ(I).展开更多
The title compound(S)-N-(2-oxoazepan-3-yl)biphenyl-4-carboxamide(C19H20N2O2, Mr = 308.37) was synthesized by the reaction of(S)-α-amino-∑-caprolactam with 4-phenyl-benzoyl chloride. Its chemical structure was determ...The title compound(S)-N-(2-oxoazepan-3-yl)biphenyl-4-carboxamide(C19H20N2O2, Mr = 308.37) was synthesized by the reaction of(S)-α-amino-∑-caprolactam with 4-phenyl-benzoyl chloride. Its chemical structure was determined by 1H NMR, 13 C NMR, H RMS and X-ray single-crystal diffraction. The crystal belongs to the triclinic system, space group P1 with a = 8.2650(17), b = 13.774(3), c = 15.109(3) ?, β = 90.20(3)o, V = 1645.6(6) ?3, Z = 4, Dc = 1.245 g/cm3, μ = 0.081 mm-1, F(000) = 656, R = 0.0756 and w R = 0.1491 for 5964 observed reflections with I > 2σ(I). The title compound was also used to prepare polyamide.展开更多
Here,a dopa decarboxylase(DDC)from Harmonia axyridis was heterogeneously expressed in Escherichia coli for the efficient biosynthesis of dopamine.For the production of recombinant DDC,the cultivation conditions includ...Here,a dopa decarboxylase(DDC)from Harmonia axyridis was heterogeneously expressed in Escherichia coli for the efficient biosynthesis of dopamine.For the production of recombinant DDC,the cultivation conditions including IPTG concentration,temperature and induction time were optimized and obtained an optimal specific enzyme activity of 51.72 U·mg^(-1) crude extracts.After the purification of DDC with a recovery yield of 68.79%,its activity was further characterized.The Vmax,Km,Kcat,and Kcat/Km of DDC for d ihyd roxy pheny la la nine(dopa)were 0.02 mmol·ml^(-1)·s^(-1),2.328 mmol·ml^(-1),10435.90 s^(-1) and4482.77 ml,mmol respectively.The highest DDC activity was observed at the condition of pH 7.5 and 45℃.With the purified DDC,the feasibility to produce dopamine from L-dopa was evaluated.The optimal yield was determined at the following bioconversion conditions:pH of 7,0,the reaction temperature of 40℃,0.4 mmol·L^(-1) of PLP and 4 g·L^(-1) of L-dopa,Subsequently,a fed-batch process for the production of dopamine was developed and the effect of oxygen was evaluated.The titer,yield and productivity of dopamine reached up to 21.99 g·L^(-1)80.88%and 14.66 g·L^(-1)·h^(-1) at 90 min under anaerobic condition.展开更多
Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-...Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.展开更多
Palmitoleic acid(POA)can be naturally found only in few oil seeds and has significant applications in pharmaceutical industry.Recently,the isolated oleaginous yeast Scheffersomyces segobiensis DSM 27193 was identified...Palmitoleic acid(POA)can be naturally found only in few oil seeds and has significant applications in pharmaceutical industry.Recently,the isolated oleaginous yeast Scheffersomyces segobiensis DSM 27193 was identified with high content of POA in its intracellular lipid(13.80%).In this study,process optimization focused on dissolved oxygen regulation to improve POA production was conducted.Dynamic agitation was found to do significant enhancement on POA-rich lipid production than aeration regulation.Under the best condition of 1000 r·min^(-1)of agitation and 1 vvm(airvolume/culture volume/min)of aeration,no ethanol was detected during the whole fermentation process,while a dry biomass concentration of 44.80 g·L^(-1)with 13.43 g·L^(-1)of lipid and 2.93 g·L^(-1)of POA was achieved.Transcription analysis revealed that the ethanol synthetic pathway was downregulated under the condition of high agitation,while the expression of the key enzymes responsible for lipid and POA accumulation were enhanced.展开更多
Milk allergy is one of the most common food allergies,affecting 6%of young children,andβ-lactoglobulin(β-LG)is the main milk allergen.Clostridium tyrobutyricum Z816 was selected for the degradation ofβ-LG,which was...Milk allergy is one of the most common food allergies,affecting 6%of young children,andβ-lactoglobulin(β-LG)is the main milk allergen.Clostridium tyrobutyricum Z816 was selected for the degradation ofβ-LG,which was successfully reduced by about 90%using permeabilized bacteria under the optimized conditions.The hydrolyzed peptides were identified by liquid chromatography-tandem mass spectrometry(LC-MS/MS)and analyzed by molecular modeling,which indicated that C.tyrobutyricum Z816 could effectively degrade the antigenic epitopes ofβ-LG.Finally,the concentration and digestibility ofβ-LG in actual samples was quantified using enzyme-linked immunosorbent assay(ELISA)and gastrointestinal digestion simulation experiments.The results showed more than 92%ofβ-LG in actual samples was hydrolyzed,and the gastric and total digestibility of whey protein isolate(WPI)was improved by 85.96%and 64.51%,respectively.Therefore,C.tyrobutyricum Z816 offers an effective method to degradeβ-LG and reduce the occurrence of milk allergies,which has great significance for the development of hypoallergenic dairy products.展开更多
基金support by National Key Research and Development Program of China(Grant No.:2023YFA0913604)Program of National Natural Science Foundation of China(Grant No.:22178170,22378195)+2 种基金Six talent peaks project in Jiangsu Province(SWYY-045)Program of National Natural Science Foundation of China(Grant No.22208155)Jiangsu Province Natural Science Foundation for Young Scholars(Grant No.BK20210552).
文摘Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.
基金supported by the High-Level Talent Research Start-Up Funds of West Anhui University(No.WGKQ2021031)Key Project of Natural Science Foundation of Anhui Province of China(No.2108085QC136)+2 种基金Key Project of Quality Engineering in Higher Education Institutions of Anhui Province(No.2020jyxm2128)National College Student Innovation and Entrepreneurship Training Program(No.202110370093)Innovation and Entrepreneurship Training Program for College Students of Anhui Province(No.S202010376114).
文摘Background:SMAD family proteins(SMADs)are crucial transcription factors downstream of transforming growth factor beta(TGF-ß)/SMAD signaling pathways that have been reported to play a pivotal role in mammalian reproduction.However,the role of SMAD family member 8(SMAD8,also known as SMAD9),a member of the SMAD family,in mammalian reproduction remains unclear.Methods:We employed RNA interference techniques to knock down Smad8 expression in mouse granulosa cells(GCs)to investigate the effects of Smad8 on GC growth and steroidogenesis.Results:Our findings revealed a significant decrease in the proliferative capacity and a substantial increase in the apoptosis rate of GCs after transfection with Smad8-siRNA for 48 h.Subsequent hormone assays demonstrated a significant decrease in estradiol(E2)levels,whereas progesterone(P4)remained unchanged.Further mechanistic analysis showed that the mRNA expression of proliferating cell nuclear antigen(Pcna),Cyclin D2,cell cycle-dependent kinase 4(Cdk4),B-cell lymphoma-2(Bcl-2),estrogen receptor(Er),luteinizing hormone receptor(Lhr)and cytochrome P450 family 19 subfamily A member 1(Cyp19a1)significantly decreased.Conversely,the mRNA of cysteine aspartate proteinase 3(Caspase 3)significantly increased,wheras Bcl2-associated X(Bax),folliclestimulating hormone receptor(Fshr)and cytochrome P450 family 11 subfamily A member 1(Cyp11a1)remained unchanged compared to the controls.Conclusion:This study indicates that Smad8 knockdown inhibits cell proliferation,promotes apoptosis,reduces Er and Lhr transcription,and decreases E2 production in mouse GCs.These findings suggest that Smad8 may serve as a novel genetic marker for mammalian reproduction.
基金supported by the National Natural Science Foundation of China(22078157)the Natural Science Foundation of the Jiangsu Higher Education institutions of China(21KJB610011)Postgraduate Research and Practice Innovation Program of Jiangsu Province(SJCX21_0468).
文摘Using N-methyl-D-glucosamine(NMDG)as the functional monomer,glycidyl methacrylate(GMA)as the connecting monomer,functionalized Fe3O4 nano-particles(NPs)as the support,three adsorbents were prepared including direct polymer GMA-NMDG,magnetic GMA-NMDG polymer(MGN),and boron magnetic ion-imprinted polymer(BMIIP).Based upon the optimization of synthesis conditions,the prepared adsorbents and intermediate products were characterized using Fourier transform infrared spectroscopy,thermogravimetric analysis,scanning electron microscope,energy dispersive spectroscopy,X-ray diffraction,vibrating sample magnetometer,and Brunauer–Emmett–Teller to investigate the synthesis process,the morphological structure and the functional properties of the materials.The optimum performances of GMA-NMDG,MGN and BMIIP were obtained in the initial neutral solution(pH of 6.5).Moreover,GMANMDG and MGN reached the maximum adsorption capacity at 120 min,whereas BMIIP reached adsorption saturation at 60 min.The pseudo-second-order kinetic model was more suitable for the adsorption of boron using the adsorbents.The maximum adsorption capacity of GMA-NMDG was found to be 43.4 mg·g^(-1),while those of MGN and BMIIP were 32.5 and 28.3 mg·g^(-1),respectively.The Langmuir isotherm model was more appropriate to describe the adsorption process.The adsorbents maintained satisfactory adsorption performance within a certain temperature range.Competing ions had little effect on the adsorption of boron,and would be adsorbed simultaneously,due to which,the effect of co-adsorption can be considered.The adsorption capacity of GMA-NMDG was high,while the adsorption selectivity of BMIIP was much better.Furthermore,BMIIP showed good adsorption after five cycles of adsorption and desorption.The comparison of adsorbents showed that GMA-NMDG had the highest adsorption capacity and was suitable for co-adsorption.MGN had a high adsorption capacity,good comprehensive performance and magnetic properties.BMIIP had better adsorption rate,adsorption selectivity and recyclability.Through the optimization of synthesis conditions,the adsorption capacity of the traditional monomer NMDG polymer was increased,and the magnetism was given to facilitate rapid recovery.Combined with the ion imprinting technology,it showed higher boron adsorption selectivity in the presence of competitive ions.
基金supported by Jiangsu Province Natural Science Foundation for Distinguished Young Scholars(BK20190035)Jiangsu Government Scholarship for Overseas Studies(JS-2019-053)+6 种基金Key Research&Development plan of Jiangsu Province(BE2019001)the National Natural Science Foundation of China(2217080044 and 22008119)the Natural Science Foundation of Jiangsu Province(BK20202002)the National Key Research and Development Program of China(2021YFC2101204)the Program for Changjiang Scholars and Innovative Research Team in University(IRT_14R28)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture.
文摘Adenylate cyclase(AC)is the key enzyme that catalyzes the formation of cAMP from ATP.In this study,we discovered two novel class Ⅲ ACs with a halophilic property from Thermobifida halotolerans DSM 44931(ThAC)and Haloactinopolyspora alba DSM 45211(HaAC),respectively.The recombinant ThAC and HaAC were expressed in Escherichia coli with molecular weights of 36.1 and 36.0 kDa respectively.The presence of 2500 and 2200 mmolL^(-1)1 NaCl significantly enhanced the enzyme activities of ThAC and HaAC,with 22-fold and 7.4-fold higher activities compared to those without NaCl,respectively.Several divalent metal ions were found to activate the recombinant ACs to different extents,and the optimal metal ion was Mg^(2+)for both ThAC and HaAC with concentrations of 80 mmol·L^(-1) and 40 mmol·L^(-1) respectively.Purified ThAC and HaAC had the optimal specific activities((4.59±0.35)×10^(4) and(7.76±0.52)×10^(4) U·mg^(-1))and catalytic efficiency(4.47 and 5.30 L·mmol^(-1)·s^(-1))at 45℃ and 40℃ respectively,while the optimum pH of both two recombinant ACs was 10.0.This is the first report of the halophilic Class III ACs,which could make new contributions to explore and study ACs for further associated investigations.
基金supported by the National Key Research and Development Program of China (2021YFC2101900 and 2019YFA0905000)National Natural Science Foundation of China (21908094, 21776130 and 22078150)+1 种基金Nanjing International Joint Research and Development Project (202002037)Top-notch Academic Programs Project of Jiangsu Higher Education Institutions。
文摘Due to the scale effect, the uniform distribution of reagents in continuous flow reactor becomes bad when the channel is enlarged to tens of millimeters. Microfluidic field strategy was proposed to produce high mixing efficiency in large-scale channel. A 3D spiral baffle structure(3SBS) was designed and optimized to form microfluidic field disturbed by continuous secondary flow in millimeter scale Y-shaped tube mixer(YSTM). Enhancement effect of the 3SBS in liquid-liquid homogeneous chemical processes was verified and evaluated through the combination of simulation and experiment. Compared with 1 mm YSTM, 10 mm YSTM with 3SBS increased the treatment capacity by 100 times, shortened the basic complete mixing time by 0.85 times, which proves the potential of microfluidic field strategy in enhancement and scale-up of liquid-liquid homogeneous chemical process.
基金the National Basic Research Program of China(2009CB724700)the Foundation of Jiangsu Province of China for College Postgraduate Students in Innovation Engineering(CXZZ12_0440)
文摘Magnetically modified palygorskite composites were synthesized with γ-Fe2O3 dispersing on the external surface of clay mineral. The magnetic clay was characterized with Fourier transform infrared, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. Candida sp. 99–125 lipase was immobilized on magnetic palygorskite composites by physical adsorption with enzyme loading of41.5 mg·g-1support and enzyme activity of 2631.6 U·(g support)-1. The immobilized lipase exhibit better thermal and broader p H stability and excellent reusability compared with free lipase.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2018YFA0901500)National Nature Science Foundation of China(Grant No.21606127,Grant No.21706126)Jiangsu synergetic innovation center for advanced bio-manufacture(Grant No.XTB1802,Grant No.XTE1844).
文摘Bio-based diamines are considered to be a promising alternative to traditional fossil-fuel-based diamines,the important platform chemical for the synthesis of polymer materials.In this review,the current status of the art of the synthesis of aliphatic and aromatic diamines from renewable biomass are considered.In the case of aliphatic diamines,we describe strategies for biologically producing diamines with different carbon numbers including 1,3-diaminopropane,1,4-butanediamine,1,5-pentanediamine,1,6-diaminohexane,1,8-diaminooctane,1,10-diaminodecane,and 1,12-diaminododecane.In addition,aromatic diamines produced from various kinds of renewable biomass,including lignin,cashew nut shell,and terpenoids,are reviewed here.Furthermore,the application of typical diamines in synthesis of polyurethane and polyamide are also reviewed.
基金The authors thank the financial support by National Natural Science Foundation of China(21776132,21878142)Jiangsu Province Natural Science Foundation for Distinguished Young Scholars(BK20190035)+2 种基金National Key Research and Development Program of China(2019YFD1101202)Jiangsu Province Natural Science Foundation for Youths(BK20200685)China Postdoctoral Science Foundation(2019M660113).
文摘Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of biocatalysis.These chemoenzymatic methods can not only save resource,cost,and operating time but also reduce the number of reaction steps,and avoid separating unstable intermediates,leading to the generation of more products under greener circumstances and thereby playing an indispensable role in the fields of medicine,materials and fine chemicals.Although incompatible challenges between chemocatalyst and biocatalyst remain,strategies such as biphasic system,artificial metalloenzymes,immobilization or supramolecular host,and protein engineering have been designed to overcome these issues.In this review,chemoenzymatic catalysis according to different chemocatalysis types was classifiably described,and in particular,the classic dynamic kinetic resolutions(DKR)and cofactor regeneration were summarized.Finally,the bottlenecks and development of chemoenzymatic catalysis were summarized,and future development was prospected.
基金Supported by the Natural Science Foundations of Xinjiang (No.2009211B06) Xinjiang University (No. QN070109)
文摘Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU). Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B. subtilis Bac01 and mutant strain Bac11. BLAST comparison result indicated that 10 nucleotides mutated. Bioinformatics methods were used to analyze the two predicted amino acid sequences, and it was found that 5 amino acid residues changed, being all in the cellulose-binding domain of endoglucanase.
基金financial support of this work from 2011 Key projects of Natural Science of Jiangsu province-owned colleges(No.11KJA610001)Innovation project designated for graduate students of Jiangsu province(No.CXZZ13_0452)the Postdoctoral research funding plan of Jiangsu province(No.1202106C)
文摘A novel benzisothiazolin-3-one derivative, 2-(benzo[d]isothiazol-3-yloxy)-N-(3-cyano-1-(4-fluorophenyl)-1H-pyrazol-5-yl) acetamide(8), was synthesized from the initial compound benzo[d]isothiazol-3(2H)-one(BIT) 1 and 4-fluoroaniline 3. The structure of the target compound 8 was determined by elemental analyses, IR and 1H NMR. The single crystals of intermediate compound 6 and the target compound 8 were obtained and determined by X-ray diffraction analysis. The preliminary biological activity was also evaluated and the results showed the target compound exhibited a good anti-microbial activity.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in University(IRT_14R28)the National Basic Research Program of China(2013CB733602)+4 种基金the Major Research Plan of the National Natural Science Foundation of China(21390204)the National Natural Science Foundation of China(21636003,21506090)Open Fund by Jiangsu Key Lab of Biomass-based Green Fuels and Chemicals(JSBGFC14005)Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.
基金Sponsored by the Natural Science Foundation of Jiangsu Province(No.BK2011088)
文摘The crystal structure of the title compound(Z)-5-fluoro-3-(phenyl((5-(pyridin-3-ylmethyl)thiophen-2-yl)amino)methylene)indolin-2-one(C_(25)H_(18)FN_3OS,M_r=427.50)has been prepared and determined by single-crystal X-ray diffraction.The crystal is of orthorhombic,space group P2_12_12_1 with a=5.931(1),b=12.413(1),c=28.102(2)A,V=2090.4(3)A^3,Z=4,D_c=1.358 g/cm^3,F(000)=888,μ=0.186 mm^(-1),MoKa radiation(λ=0.71073),R=0.041 and wR=0.105 for 4567 observed reflections with I>2σ(I).X-ray diffraction analysis reveals that the indole and thiophene rings are not coplanar with a dihedral angle of 46.26(5)°.Intramolecular and intermolecular N-H…O hydrogen bonds together with C-H…πinterations can be observed in the lattice.
基金supported by Jiangsu Key Lab of Biomass-based Green Fuels and Chemicals Foundation(JSBEM2016010),Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture of China.
文摘Exopolysaccharides can be produced by various bacteria and have important biological roles in bacterial survival depend on molecular weight,linkage,and conformation.In this study,Leuconostoc pseudomesenteroides G29 was identified and found to produce two types of exopolysaccharides from sucrose including soluble and insoluble a-glucans.By regulation of pH above 5.5,soluble a-glucan production was increased to 38.4 g∙L^(-1) from 101.4 g∙L^(-1) sucrose with fewer accumulation of lactic acid and acetic acid.Simultaneously,the quantity of thick white precipitate,that is insoluble a-glucan,was also increased.Then,a-glucans were prepared by enzymatic reaction with crude glucansucrases from the supernatant of G29 fermentation broth and purified for structure analysis.Based on the integration analysis of FT-IR and NMR,it was observed that soluble a-glucan is a highly linear dextran with α-1,6 glycosidic bonds while the insoluble a-glucan has 93%of α-1,3 and 7%of α-1,6 glycosidic bond.The results extend our understanding of exopolysaccharides production by L.pseudomesenteroides,and this water insoluble α-1,3-glucan might have potential application as biomaterials and/or biochemicals.
基金supported by National Key Research and Development Program of China (2020YFE0100100, 2021YFC21041002018YFA0901500)+1 种基金Basic Science (Natural Science) Research Project of Jiangsu Province Colleges and Universities(21KJB530014)Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture
文摘Compared with conventional cylinder airlift bioreactors(CCABs)that produce coarse bubbles,a novel rectangular dynamic membrane airlift bioreactor(RDMAB)developed in our lab produces fine bubbles to enhance the volumetric oxygen mass transfer coefficient(k_(L)a)and gas holdup,as well as improve the bioprocess in a bioreactor.In this study,we compared mass transfer,gas holdup,and batch and con-tinuous fermentation for RNA production in CCAB and RDMAB.In addition,unstructured kinetic models for microbial growth,substrate utilization,and RNA formation were established.In batch fermentation,biomass,RNA yield,and substrate utilization in the RDMAB were higher than those in the CCAB,which indicates that dynamic membrane aeration produced a high k_(L)a by fine bubbles;a higher k_(L)a is more bene-ficial to aerobic fermentation.The starting time of continuous fermentation in the RDMAB was 20 h ear-lier than that in the CCAB,which greatly improved the biological process.During continuous fermentation,maintaining the same dissolved oxygen level and a constant dilution rate,the biomass accumulation and RNA concentration in the RDMAB were 9.71% and 11.15% higher than those in the CCAB,respectively.Finally,the dilution rate of RDMAB was 16.7% higher than that of CCAB during con-tinuous fermentation while maintaining the same air aeration.In summary,RDMAB is more suitable for continuous fermentation processes.Developing new aeration and structural geometry in airlift bioreac-tors to enhance k_(L)a and gas holdup is becoming increasingly important to improve bioprocesses in a bioreactor.
基金Supported by the National Key Basic Research Program of China(973 Program)(2012CB725204 and 2012CB721104)the Natural Science Foundation of Jiangsu Province(No.BK20130913)+1 种基金Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1066)the Priority Academic Program Development of Jiangsu Higher Education Institution
文摘The title compound(S)-N-(hexahydro-2-oxo-1H-azepin-3-yl)-3-phenyl-2-propenamide(C15H18N2O2, Mr = 258.31) was synthesized by the reaction of(S)-α-amino-ε-caprolactam with 3-phenyl-2- propenoyl chloride. Its chemical structure was determined by 1H NMR, 13C NMR, H RMS and X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 14.957(3), b = 4.884(1), c = 18.630(4), β = 95.91(3)o, V = 1353.7(5)3, Z = 4, Dc = 1.267 g/cm3, μ = 0.085 mm-1, F(000) = 552, R = 0.0671 and wR = 0.1547 for 2473 observed reflections with I > 2σ(I).
基金Supported by the National Key Basic Research Program of China(973 Program,2012CB725204 and 2012CB721104)the Natural Science Foundation of Jiangsu Province(No.BK20130913)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1066)
文摘The title compound(S)-N-(2-oxoazepan-3-yl)biphenyl-4-carboxamide(C19H20N2O2, Mr = 308.37) was synthesized by the reaction of(S)-α-amino-∑-caprolactam with 4-phenyl-benzoyl chloride. Its chemical structure was determined by 1H NMR, 13 C NMR, H RMS and X-ray single-crystal diffraction. The crystal belongs to the triclinic system, space group P1 with a = 8.2650(17), b = 13.774(3), c = 15.109(3) ?, β = 90.20(3)o, V = 1645.6(6) ?3, Z = 4, Dc = 1.245 g/cm3, μ = 0.081 mm-1, F(000) = 656, R = 0.0756 and w R = 0.1491 for 5964 observed reflections with I > 2σ(I). The title compound was also used to prepare polyamide.
基金funded by the National Natural Science Foundation of China(21576134 and 21706126)the National Key Research and Development Program(2016YFA0204300)。
文摘Here,a dopa decarboxylase(DDC)from Harmonia axyridis was heterogeneously expressed in Escherichia coli for the efficient biosynthesis of dopamine.For the production of recombinant DDC,the cultivation conditions including IPTG concentration,temperature and induction time were optimized and obtained an optimal specific enzyme activity of 51.72 U·mg^(-1) crude extracts.After the purification of DDC with a recovery yield of 68.79%,its activity was further characterized.The Vmax,Km,Kcat,and Kcat/Km of DDC for d ihyd roxy pheny la la nine(dopa)were 0.02 mmol·ml^(-1)·s^(-1),2.328 mmol·ml^(-1),10435.90 s^(-1) and4482.77 ml,mmol respectively.The highest DDC activity was observed at the condition of pH 7.5 and 45℃.With the purified DDC,the feasibility to produce dopamine from L-dopa was evaluated.The optimal yield was determined at the following bioconversion conditions:pH of 7,0,the reaction temperature of 40℃,0.4 mmol·L^(-1) of PLP and 4 g·L^(-1) of L-dopa,Subsequently,a fed-batch process for the production of dopamine was developed and the effect of oxygen was evaluated.The titer,yield and productivity of dopamine reached up to 21.99 g·L^(-1)80.88%and 14.66 g·L^(-1)·h^(-1) at 90 min under anaerobic condition.
基金supported by grants from the National Key Research and Development Program of China(2021YFC2102805,2019YFD1101204)the National Natural Science Foundation of China(21878142,21776132)+3 种基金Key Research and Development Plan of Jiangsu Province(BE2020712)Key Research and Development Plan of Jiangsu Province(BE2019001)Jiangsu Natural Science Fund for Distinguished Young Scholars(BK20190035)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.
基金supported by the National Key Research & Development Program of China (2021YFC2101500, 2018YFA0902200)National Natural Science Foundation of China (22008115, 21978130)+4 种基金Jiangsu Province Natural Science Foundation for Youths (SBK2020044721)Jiangsu Provincial Agricultural Science and Technology Independent Innovation Fund Project (CX(21)3120)Jiangsu Planned Projects for Postdoctoral Research Funds (2021K085A)China Postdoctoral Science Foundation (2020M671467)Postdoctoral Research Funding Program of Jiangsu Province (2021K085A)
文摘Palmitoleic acid(POA)can be naturally found only in few oil seeds and has significant applications in pharmaceutical industry.Recently,the isolated oleaginous yeast Scheffersomyces segobiensis DSM 27193 was identified with high content of POA in its intracellular lipid(13.80%).In this study,process optimization focused on dissolved oxygen regulation to improve POA production was conducted.Dynamic agitation was found to do significant enhancement on POA-rich lipid production than aeration regulation.Under the best condition of 1000 r·min^(-1)of agitation and 1 vvm(airvolume/culture volume/min)of aeration,no ethanol was detected during the whole fermentation process,while a dry biomass concentration of 44.80 g·L^(-1)with 13.43 g·L^(-1)of lipid and 2.93 g·L^(-1)of POA was achieved.Transcription analysis revealed that the ethanol synthetic pathway was downregulated under the condition of high agitation,while the expression of the key enzymes responsible for lipid and POA accumulation were enhanced.
基金supported by the National Key R&D Program of China(2017YFC1600404)the National Natural Science Foundation of China(31922070,22008114)the Natural Science Foundation of Jiangsu Province(BK20180038,BK20200684)。
文摘Milk allergy is one of the most common food allergies,affecting 6%of young children,andβ-lactoglobulin(β-LG)is the main milk allergen.Clostridium tyrobutyricum Z816 was selected for the degradation ofβ-LG,which was successfully reduced by about 90%using permeabilized bacteria under the optimized conditions.The hydrolyzed peptides were identified by liquid chromatography-tandem mass spectrometry(LC-MS/MS)and analyzed by molecular modeling,which indicated that C.tyrobutyricum Z816 could effectively degrade the antigenic epitopes ofβ-LG.Finally,the concentration and digestibility ofβ-LG in actual samples was quantified using enzyme-linked immunosorbent assay(ELISA)and gastrointestinal digestion simulation experiments.The results showed more than 92%ofβ-LG in actual samples was hydrolyzed,and the gastric and total digestibility of whey protein isolate(WPI)was improved by 85.96%and 64.51%,respectively.Therefore,C.tyrobutyricum Z816 offers an effective method to degradeβ-LG and reduce the occurrence of milk allergies,which has great significance for the development of hypoallergenic dairy products.
