Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut microbiota.MD 0s,MD 5s and MD 60s represente...Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut microbiota.MD 0s,MD 5s and MD 60s represented brown rice,moderately-milled rice and white rice,respectively.After in vitro fermentation,the MD 5s group showed higher starch utilization,compared with the MD 0s and 60s groups evaluated by Fourier transform infrared spectrometer,and confocal laser scanning microscope.Effects of fermentation substrates of rice with different MDs on gut microbiota were evaluated by 16S rDNA sequencing.All the sample groups reduced the pH and produced short-chain fatty acids(SCFAs) and branched-chain fatty acids.The MD 5s group exhibited higher α-diversity than the MD 0s and 60s groups.Abundances of Phascolarctobacterium,Blautia and norank_f_Ruminococcaceae were higher in the MD 0s and 5s groups,compared with the MD 60s group.These bacteria were also positively correlated with the SCFAs production via Spearman correlation analysis.In vitro culture assay revealed that fermentation substrates of MD 0s and 5s promoted the growth of two probiotics(Akkermansia muciniphila and Bifidobacterium adolescentis).Our results showed that moderate milling might be an appropriate way to produce rice products with richer nutrients and better fermentation properties.展开更多
Most accidents of centrifugal compressors are caused by fluid pulsation or unsteady fluid excitation.Rotating stall,as an unstable flow phenomenon in the compressor,is a difficult point in the field of fluid machinery...Most accidents of centrifugal compressors are caused by fluid pulsation or unsteady fluid excitation.Rotating stall,as an unstable flow phenomenon in the compressor,is a difficult point in the field of fluid machinery research.In this paper,a stack denoising kernel autoencoder neural network method is proposed to study the early warning of rotating stall in a centrifugal compressor.By collecting the pressure pulsation signals of the centrifugal compressor under different flow rates in engineering practice,a double hidden layer sparse denoising autoencoder neural network is constructed.According to the output labels of the network,it can be judged whether the rotation stall occurs.At the same time,the Gaussian kernel is used to optimize the loss function of the whole neural network to improve the signal feature learning ability of the network.From the experimental results,it can be seen that the flow state of the centrifugal compressor is accurately judged,and the rotation stall early warning of the centrifugal compressor at different speeds is realized,which lays a foundation for the research of intelligent operation and maintenance of the centrifugal compressor.展开更多
Biosynthesis of the functional factor𝛾γ-aminobutyric acid(GABA)in bacteria involves two key proteins an intra-cellular glutamate decarboxylase(GadB)and a membrane-bound antiporter(GadC).Efficient co-expressio...Biosynthesis of the functional factor𝛾γ-aminobutyric acid(GABA)in bacteria involves two key proteins an intra-cellular glutamate decarboxylase(GadB)and a membrane-bound antiporter(GadC).Efficient co-expression of suitable GadB and GadC candidates is crucial for improving GABA productivity.In this study,gadBΔC11 of Lacti-plantibacillus plantarum and gadCΔC41 of Escherichia coli were inserted into the designed double promoter(P T7lac and P BAD)expression system.Then,E.coli Lemo21(DE3)was chosen as the host to minimize the toxic effects of GadCΔC41 overexpression.Furthermore,a green and high-efficiency GABA synthesis system using dormant engineered Lemo21(DE3)cells as biocatalysts was developed.The total GABA yield reached 829.08 g/L with a 98.7%conversion ratio within 13 h,when engineered E.coli Lemo21(DE3)cells were concentrated to an OD 600 of 20 and reused for three cycles in a 3 M L-glutamate solution at 37℃,which represented the highest GABA productivity ever reported.Overall,expanding the active pH ranges of GadB and GadC toward physiological pH and employing a tunable expression host for membrane-bound GadC production is a promising strategy for high-level GABA biosynthesis in E.coli.展开更多
This research aims to change the phenolic fractions and the bioactivities of quinoa by solid-state fermentation(SSF)with the edible fungus Monascus anka(M.anka).The contents of protein and fat increased in the ferment...This research aims to change the phenolic fractions and the bioactivities of quinoa by solid-state fermentation(SSF)with the edible fungus Monascus anka(M.anka).The contents of protein and fat increased in the fermented product,while the carbohydrate decreased.After 6-day fermentation with M.anka,the amount of phenolic compound reached the highest level.The majority of phenolic forms in fermented quinoa were phenolic acids,mainly ferulic acid,protocatechuic acid and p-hydroxybenzoic acid.Ultrahigh-performance liquid chromatography-mass spectrometry(UHPLC-MS)results showed that SSF was an effective method to transform quinoa phenolic compounds.Free fractions could be rapidly absorbed in the small intestine,suggesting that SSF with M.anka was a useful method to enhance bioavailable antioxidants.Antioxidant ability in vitro results showed that phenolic fractions from fermented quinoa were greater than the unfermented quinoa,and a significant cellular antioxidant activity(CAA)increment of 135%was obtained in the free phenolic fraction of fermented quinoa.Moreover,α-amylase andα-glucosidase inhibition activities were enhanced with fermentation.Correlation matrix analysis revealed that most of the free phenolic compounds showed strong positive correlations with antioxidant activities and digestive enzyme activities.Consequently,fermentation with M.anka was a particularly promising method to enhance the bioactivity of quinoa.展开更多
基金supported by the National Natural Science Foundation of China (32202051)the Shanghai Sailing Program (21YF1431800, 20YF1433400)+1 种基金Shanghai Agriculture Applied Technology Development Program, China (2021-02-08-0012-F00780 )the National Key R&D Program of China (2022YFF1100104, 2023YFF1103404)。
文摘Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut microbiota.MD 0s,MD 5s and MD 60s represented brown rice,moderately-milled rice and white rice,respectively.After in vitro fermentation,the MD 5s group showed higher starch utilization,compared with the MD 0s and 60s groups evaluated by Fourier transform infrared spectrometer,and confocal laser scanning microscope.Effects of fermentation substrates of rice with different MDs on gut microbiota were evaluated by 16S rDNA sequencing.All the sample groups reduced the pH and produced short-chain fatty acids(SCFAs) and branched-chain fatty acids.The MD 5s group exhibited higher α-diversity than the MD 0s and 60s groups.Abundances of Phascolarctobacterium,Blautia and norank_f_Ruminococcaceae were higher in the MD 0s and 5s groups,compared with the MD 60s group.These bacteria were also positively correlated with the SCFAs production via Spearman correlation analysis.In vitro culture assay revealed that fermentation substrates of MD 0s and 5s promoted the growth of two probiotics(Akkermansia muciniphila and Bifidobacterium adolescentis).Our results showed that moderate milling might be an appropriate way to produce rice products with richer nutrients and better fermentation properties.
基金supported through the Joint Funds of the National Natural Science Foundation of China (Grant No.U1808214)National Key Research and Development Project (Grant No.2020YFB2010800)the National Natural Science Foundation of China (Grant No.92060105).
文摘Most accidents of centrifugal compressors are caused by fluid pulsation or unsteady fluid excitation.Rotating stall,as an unstable flow phenomenon in the compressor,is a difficult point in the field of fluid machinery research.In this paper,a stack denoising kernel autoencoder neural network method is proposed to study the early warning of rotating stall in a centrifugal compressor.By collecting the pressure pulsation signals of the centrifugal compressor under different flow rates in engineering practice,a double hidden layer sparse denoising autoencoder neural network is constructed.According to the output labels of the network,it can be judged whether the rotation stall occurs.At the same time,the Gaussian kernel is used to optimize the loss function of the whole neural network to improve the signal feature learning ability of the network.From the experimental results,it can be seen that the flow state of the centrifugal compressor is accurately judged,and the rotation stall early warning of the centrifugal compressor at different speeds is realized,which lays a foundation for the research of intelligent operation and maintenance of the centrifugal compressor.
基金This work was supported by Natural Science Foundation of Zhe-jiang Province(LY23B060001)Zhejiang Provincial Key R&D Pro-gram of China(2021C02049)+2 种基金China Postdoctoral Science Founda-tion(2020M671337)National Natural Science Foundation of China(31670804,31971372)Ningbo"Scientific and Technological In-novation 2025″Key Project(2020Z080,2020Z088).
文摘Biosynthesis of the functional factor𝛾γ-aminobutyric acid(GABA)in bacteria involves two key proteins an intra-cellular glutamate decarboxylase(GadB)and a membrane-bound antiporter(GadC).Efficient co-expression of suitable GadB and GadC candidates is crucial for improving GABA productivity.In this study,gadBΔC11 of Lacti-plantibacillus plantarum and gadCΔC41 of Escherichia coli were inserted into the designed double promoter(P T7lac and P BAD)expression system.Then,E.coli Lemo21(DE3)was chosen as the host to minimize the toxic effects of GadCΔC41 overexpression.Furthermore,a green and high-efficiency GABA synthesis system using dormant engineered Lemo21(DE3)cells as biocatalysts was developed.The total GABA yield reached 829.08 g/L with a 98.7%conversion ratio within 13 h,when engineered E.coli Lemo21(DE3)cells were concentrated to an OD 600 of 20 and reused for three cycles in a 3 M L-glutamate solution at 37℃,which represented the highest GABA productivity ever reported.Overall,expanding the active pH ranges of GadB and GadC toward physiological pH and employing a tunable expression host for membrane-bound GadC production is a promising strategy for high-level GABA biosynthesis in E.coli.
基金This work was supported by Shanghai Agriculture Applied Technology Development Program,China(2021-02-08-00-12-F00780)the Shanghai Committee of Science and Technology,China(20DZ2202700)+1 种基金the Capacity-Building Project of Local Universities of SSTC(20060502100)the Shanghai Sailing Program(21YF1431800)and(20YF1433400).
文摘This research aims to change the phenolic fractions and the bioactivities of quinoa by solid-state fermentation(SSF)with the edible fungus Monascus anka(M.anka).The contents of protein and fat increased in the fermented product,while the carbohydrate decreased.After 6-day fermentation with M.anka,the amount of phenolic compound reached the highest level.The majority of phenolic forms in fermented quinoa were phenolic acids,mainly ferulic acid,protocatechuic acid and p-hydroxybenzoic acid.Ultrahigh-performance liquid chromatography-mass spectrometry(UHPLC-MS)results showed that SSF was an effective method to transform quinoa phenolic compounds.Free fractions could be rapidly absorbed in the small intestine,suggesting that SSF with M.anka was a useful method to enhance bioavailable antioxidants.Antioxidant ability in vitro results showed that phenolic fractions from fermented quinoa were greater than the unfermented quinoa,and a significant cellular antioxidant activity(CAA)increment of 135%was obtained in the free phenolic fraction of fermented quinoa.Moreover,α-amylase andα-glucosidase inhibition activities were enhanced with fermentation.Correlation matrix analysis revealed that most of the free phenolic compounds showed strong positive correlations with antioxidant activities and digestive enzyme activities.Consequently,fermentation with M.anka was a particularly promising method to enhance the bioactivity of quinoa.
