Pichia stipitis CBS 5773 yeast cells were used to ferment the mixed substrates consisted of glucose andxylose to produce ethanol.The effects of aeration rate,initial substrate concentration and pH on substrateutilizat...Pichia stipitis CBS 5773 yeast cells were used to ferment the mixed substrates consisted of glucose andxylose to produce ethanol.The effects of aeration rate,initial substrate concentration and pH on substrateutilization and ethanol yield were evaluated.During batch fermentation,the oscillation phenomena in cell growthwere observed at low aeration rate,whereas the diauxic growth at high aeration rate.The substrate utilizationratio and ethanol yield reached 95％ and 0.46g/g respectively under appropriate operation conditions.Amodified unstructural model was proposed to simulate the diauxic cell growth,substrate consumption andproduct formation.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
文摘Pichia stipitis CBS 5773 yeast cells were used to ferment the mixed substrates consisted of glucose andxylose to produce ethanol.The effects of aeration rate,initial substrate concentration and pH on substrateutilization and ethanol yield were evaluated.During batch fermentation,the oscillation phenomena in cell growthwere observed at low aeration rate,whereas the diauxic growth at high aeration rate.The substrate utilizationratio and ethanol yield reached 95％ and 0.46g/g respectively under appropriate operation conditions.Amodified unstructural model was proposed to simulate the diauxic cell growth,substrate consumption andproduct formation.
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.
