Improvements In Ethanologenic Escherichia Coli and Klebsiella Oxytoca

Dr. David Nunn

关键词: BIOMASS;    DISTILLATION;    ENZYMES;    ESCHERICHIA COLI;    ETHANOL;    FERMENTATION;    HEXOSES;    KLEBSIELLA;    PENTOSES;    SACCHARIDES;    SACCHARIFICATION;    STRAINS;    TOLERANCE;   

DOI  :  10.2172/992134
RP-ID  :  DOEGO17058
PID  :  OSTI ID: 992134
Others  :  TRN: US201022%%387

学科分类：燃料技术

美国|英语

来源: SciTech Connect

【 摘 要 】

The current Verenium cellulosic ethanol process is based on the dilute-acid pretreatment of a biomass feedstock, followed by a two-stage fermentation of the pentose sugar-containing hydrolysate by a genetically modified ethanologenic Escherichia coli strain and a separate simultaneous saccharification-fermentation (SSF) of the cellulosic fraction by a genetically modified ethanologenic Klebsiella oxytoca strain and a fungal enzyme cocktail. In order to reduce unit operations and produce a fermentation beer with higher ethanol concentrations to reduce distillation costs, we have proposed to develop a simultaneous saccharification co-fermentation (SScF) process, where the fermentation of the pentose-containing hydrolysate and cellulosic fraction occurs within the same fermentation vessel. In order to accomplish this goal, improvements in the ethanologens must be made to address a number of issues that arise, including improved hydrolysate tolerance, co-fermentation of the pentose and hexose sugars and increased ethanol tolerance. Using a variety of approaches, including transcriptomics, strain adaptation, metagenomics and directed evolution, this work describes the efforts of a team of scientists from Verenium, University of Florida, Massachusetts Institute of Technology and Genomatica to improve the E. coli and K. oxytoca ethanologens to meet these requirements.