Inventor(s): Shengde Zhou
Abstract
This invention provides a method of producing ethanol from cellulosic biomass that includes a method for fermenting bacteria and for making a bacterial derivative including engineering a native homoethanol pathway without addition of foreign genes or promoters. Steps include deleting genes that are competitive with ethanol production pathways and performing transcriptional gene fusion for highly anaerobic expression of pyruvate dehydrogenase (PDH) operon. The PDH generates additional NADH needed for the homoethanol pathway (pyruvate-to-acetyl-CoA-to-acetaldehyde-to-ethanol). The developed strain ferments both glucose and xylose into ethanol achieving 90 % yields under anaerobic conditions. This approach can be used in strain development for production of biobutanol, biohydrogen, and microbial fuel cells as well, which are also alternative fuel sources.
Potential commercial use and users:
Production of alternative fuel ethanol, chemicals and solvents.
Advantages:
This method reduces the reliance on starch-based supply feed for ethanol production, such as corn, which has other competing commercial uses, such as for food and feedstock uses. A cellulosic biomass feed supply for the invention method has large scale availability. The deletion of specific genes and elimination of competing fermentation pathways provided by this method increases the yield of ethanol from the bacteria. The novel pathway technology can be engineered in other suitable bacteria that contain a pathway for ethanol production.
Related Publications:
Zhou, S., A. Iverson, and W. S. Graburn. 2008. Engineering a native homoethanol pathway in Escherichia coli B for ethanol production. Biotechnology Lett. 30(2):335-342.
Status: Patent Pending
Contact Us