ZYMOMONAS PENTOSE-SUGAR FERMENTATING STRAINS AND USES THEREOF

摘要

A Zymomonas integrant posseses the ability to ferment pentose into ethanol. The operon encoding for the pentose-fermenting enzymes are integrated into the Zymomonas genome in a two-integration event of homologous recombination and transposition. Each operon may include more than one pentose-reducing enzyme encoding sequence. The integrant in some embodiments includes enzyme sequences encoding xylose isomerase, xylulokinase, transketolase and transaldolase. The Zymomonas integrants are highly stable, and retain activity for producing the pentose-fermenting enzyme for between 80 to 160 generations. The integrants are also resistant to acetate inhibition, as the integrants demonstrate efficient ethanol production even in the presence of 8 up to 16 grams acetate per liter media.