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
The development of economically feasible bio-based process requires efficient cell factories capable of producing the desired product at high titer under high-cell-density fermentation.Herein we present a combinatoria...The development of economically feasible bio-based process requires efficient cell factories capable of producing the desired product at high titer under high-cell-density fermentation.Herein we present a combinatorial approach based on systems metabolic engineering and metabolic evolution for the development of efficient biomass-producing strain.Systems metabolic engineering guided by flux balance analysis(FBA)was first employed to rationally design mutant strains of Scheffersomyces stipitis with high biomass yield.By experimentally implementing these mutations,the biomass yield was improved by 30%in GPD1,25%in TKL1,30%in CIT1,and 44%in ZWF1 overexpressed mutants compared to wild-type.These designed mutants were further fine-tuned through metabolic evolution resulting in the maximal biomass yield of 0.49 g-cdw/g-glucose,whichmatcheswell with predicted yield phenotype.The constructed mutants are beneficial for biotechnology applications dealing with high cell titer cultivations.This work demonstrates a solid confirmation of systems metabolic engineering in combination with metabolic evolution approach for efficient strain development,which could assist in rapid optimization of cell factory for an economically viable and sustainable bio-based process.展开更多
Microbial production of chemicals and proteins from biomass-derived andwaste sugar streams is a rapidly growing area of research and development.While the model yeast Saccharomyces cerevisiae is an excellent host for ...Microbial production of chemicals and proteins from biomass-derived andwaste sugar streams is a rapidly growing area of research and development.While the model yeast Saccharomyces cerevisiae is an excellent host for the conversion of glucose to ethanol,production of other chemicals from alternative substrates often requires extensive strain engineering.To avoid complex and intensive engineering of S.cerevisiae,other yeasts are often selected as hosts for bioprocessing based on their natural capacity to produce a desired product:for example,the efficient production and secretion of proteins,lipids,and primary metabolites that have value as commodity chemicals.Even when using yeasts with beneficial native phenotypes,metabolic engineering to increase yield,titer,and production rate is essential.The non-conventional yeasts Kluyveromyces lactis,K.marxianus,Scheffersomyces stipitis,Yarrowia lipolytica,Hansenula polymorpha and Pichia pastoris have been developed as eukaryotic hosts because of their desirable phenotypes,including thermotolerance,assimilation of diverse carbon sources,and high protein secretion.However,advanced metabolic engineering in these yeasts has been limited.This review outlines the challenges of using non-conventional yeasts for strain and pathway engineering,and discusses the developed solutions to these problems and the resulting applications in industrial biotechnology.展开更多
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Platform Technology grant from National Center for Genetic Engineering and Biotechnology,Thailand(No.P-13-50084).
文摘The development of economically feasible bio-based process requires efficient cell factories capable of producing the desired product at high titer under high-cell-density fermentation.Herein we present a combinatorial approach based on systems metabolic engineering and metabolic evolution for the development of efficient biomass-producing strain.Systems metabolic engineering guided by flux balance analysis(FBA)was first employed to rationally design mutant strains of Scheffersomyces stipitis with high biomass yield.By experimentally implementing these mutations,the biomass yield was improved by 30%in GPD1,25%in TKL1,30%in CIT1,and 44%in ZWF1 overexpressed mutants compared to wild-type.These designed mutants were further fine-tuned through metabolic evolution resulting in the maximal biomass yield of 0.49 g-cdw/g-glucose,whichmatcheswell with predicted yield phenotype.The constructed mutants are beneficial for biotechnology applications dealing with high cell titer cultivations.This work demonstrates a solid confirmation of systems metabolic engineering in combination with metabolic evolution approach for efficient strain development,which could assist in rapid optimization of cell factory for an economically viable and sustainable bio-based process.
基金This work was supported by NSF CBET-1510697 and -1403264.
文摘Microbial production of chemicals and proteins from biomass-derived andwaste sugar streams is a rapidly growing area of research and development.While the model yeast Saccharomyces cerevisiae is an excellent host for the conversion of glucose to ethanol,production of other chemicals from alternative substrates often requires extensive strain engineering.To avoid complex and intensive engineering of S.cerevisiae,other yeasts are often selected as hosts for bioprocessing based on their natural capacity to produce a desired product:for example,the efficient production and secretion of proteins,lipids,and primary metabolites that have value as commodity chemicals.Even when using yeasts with beneficial native phenotypes,metabolic engineering to increase yield,titer,and production rate is essential.The non-conventional yeasts Kluyveromyces lactis,K.marxianus,Scheffersomyces stipitis,Yarrowia lipolytica,Hansenula polymorpha and Pichia pastoris have been developed as eukaryotic hosts because of their desirable phenotypes,including thermotolerance,assimilation of diverse carbon sources,and high protein secretion.However,advanced metabolic engineering in these yeasts has been limited.This review outlines the challenges of using non-conventional yeasts for strain and pathway engineering,and discusses the developed solutions to these problems and the resulting applications in industrial biotechnology.
