BIOCATALYSTS FOR PRODUCTION OF BIOETHANOL

Authors: Bothast, Rodney; Nichols, Nancy; Dien, Bruce; Cotta, Michael

Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2002
Publication Date: 8/15/2002
Citation: BOTHAST, R.J., NICHOLS, N.N., DIEN, B.S., COTTA, M.A. BIOCATALYSTS FOR PRODUCTION OF BIOETHANOL. SOCIETY OF INDUSTRIAL MICROBIOLOGY ANNUAL MEETING. 2002. PAPER NO. 12-1.

Interpretive Summary:

Technical Abstract: One of the major technical obstacles to commercialization of a process for converting biomass to fuel ethanol is strain development. Traditional microorganisms used for ethanol fermentation (e.g., Saccharomyces cerevisiae and Zymomonas mobilis) do not metabolize pentose sugars. Consequently, considerable effort has been expended searching for pentose-fermenting organisms. Initially, three naturally occurring yeasts (Pachysolen tannophilus, Pichia stipitis, and Candida shehatae) were discovered and received considerable attention. Much of the more recent work to improve the fermentation yield of multiple substrates has been in the development of genetically engineered microorganisms. Two fundamental molecular approaches have evolved for the development of superior ethanologenic microorganisms that can ferment pentose and hexose sugars. The first approach is to genetically engineer the ability to use biomass sugars in microorganisms (such as S. cerevisiae and Z. mobilis) that normally produce ethanol. The second approach is to engineer enhanced ethanol production in microorganisms (such as Escherichia coli and Gram positive bacteria) that naturally use biomass sugars. Previously, an industrial process was engineered to suit the microorganism. Today, we expect to metabolically engineer the microorganisms to fit the process. Future work will see improvements in existing strains through strain adaptation and further genetic engineering and also the development of new ethanol-producing microorganisms.