Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7080159 | Bioresource Technology | 2013 | 32 Pages |
Abstract
The d-lactic acid producing strain, Escherichia coli HBUT-D, was reengineered for l(+)-lactic acid fermentation by replacing the d-lactate dehydrogenase gene (ldhA) with an l(+)-lactate dehydrogenase gene (ldhL) from Pedicoccus acidilactici, followed by adaptive evolution in sucrose. The resulting strain, WYZ-L, has enhanced expression of the sucrose operon (cscA and cscKB). In 100 g Lâ1 of sucrose fermentation using mineral salt medium, WYZ-L produced 97 g Lâ1 of l(+)-lactic acid, with a yield of 90%, a maximum productivity of 3.17 g Lâ1 hâ1 and an optical purity of greater than 99%. In fermentations using sugarcane molasses and corn steep liquor without additional nutrients, WYZ-L produced 75 g Lâ1 of l(+)-lactic acid, with a yield of 85%, a maximum productivity of 1.18 g Lâ1 hâ1, and greater than 99% optical purity. These results demonstrated that WYZ-L has the potential to use waste molasses and corn steep liquor as a resource for l(+)-lactic acid fermentation.
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Authors
Yongze Wang, Kunpeng Li, Feng Huang, Jinhua Wang, Jinfang Zhao, Xiao Zhao, Erin Garza, Ryan Manow, Scott Grayburn, Shengde Zhou,