Engineering and adaptive evolution of Escherichia coli W for L-lactic acid fermentation from molasses and corn steep liquor without additional nutrients.
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 L(-1) of sucrose fermentation using mineral salt medium, WYZ-L produced 97 g L(-1) of l(+)-lactic acid, with a yield of 90%, a maximum productivity of 3.17 g L(-1)h(-1) 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 L(-1) of l(+)-lactic acid, with a yield of 85%, a maximum productivity of 1.18 g L(-1)h(-1), 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.
Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering, Ministry of Education, College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China.
Yongze
Y
Wang
Kunpeng
K
Li
Feng
F
Huang
Jinhua
J
Wang
Jinfang
J
Zhao
Xiao
X
Zhao
Erin
E
Garza
Ryan
R
Manow
Scott
S
Grayburn
Shengde
S
Zhou
D000220:Adaptation, Biological; D004926:Escherichia coli / Q000235:genetics*; D005285:Fermentation; D005818:Genetic Engineering; D005947:Glucose / Q000378:metabolism; D045022:Lactate Dehydrogenases / Q000378:metabolism; D019344:Lactic Acid / Q000096:biosynthesis*; D008965:Molasses; D013395:Sucrose / Q000378:metabolism; D014866:Waste Products / Q000032:analysis; D003313:Zea mays / Q000378:metabolism*
D014866:Waste Products; D019344:Lactic Acid; D013395:Sucrose; D045022:Lactate Dehydrogenases; C071195:D-lactate dehydrogenase; D005947:Glucose
Adaptive evolution; Escherichia coli; Molasses; Sucrose fermentation; l(+)-Lactic acid