Submitted to: International Starch Technology Conference
Publication Type: Proceedings
Publication Acceptance Date: 6/6/2007
Publication Date: 6/6/2007
Citation: Dien, B.S. 2007. A primer for lignocellulose biochemical conversion to fuel ethanol. Proceedings of the Fifth International Starch Technology Conference. p. 5.1-5.9.
Technical Abstract: Meeting the future needs for bioethanol in the marketplace depends upon developing lignocellulose as a feedstock for production. The major obstacles to using lignocellulose as a feedstock remain capital and production costs and their associated risks. However, technological advancements have continued to erode these barriers and there now exists interests in commercializing the available technology. Major technical advancements have included improvement in dilute-acid for treatment of higher solids and development of lower-waste pretreatment strategies. Advancements in cellulase enzymes have lowered the cost of these preparations, while improving their efficiency. Future advancements are promised by selective inclusion of auxiliary enzymatic activities such as xylanases. Perhaps the most significant advancement has occurred in the area of developing more robust biocatalysts that have the ability to ferment pentose sugars. Two general strategies have been pursued. In the cases of Zymomonas mobilis and Saccharomyces cerevisiae, these naturally efficient ethanol producers have been engineered to utilize pentoses. Alternately, Gram negative bacteria (i.e., Escherichia coli and Klebsiella oxytoca), which naturally utilize pentoses, have been successfully engineered to selectively produce ethanol. Continued improvements include developing hardier strains as well as strains capable of producing hydrolytic enzymes. Recent progress has also been made in developing Gram positive and thermophilic bacteria as ethanol producing biocatalysts.