title: Enhanced L-lactic acid production from biomass-derived xylose by a mutant Bacillus coagulans.
abstract: Xylose effective utilization is crucial for production of bulk chemicals from low-cost lignocellulosic substrates. In this study, an efficient L-lactate production process from xylose by a mutant Bacillus coagulans NL-CC-17 was demonstrated. The nutritional requirements for L-lactate production by B. coagulans NL-CC-17 were optimized statistically in shake flask fermentations. Corn steep liquor powder and yeast exact were identified as the most significant factors by the two-level Plackett-Burman design. Steepest ascent experiments were applied to approach the optimal region of the two factors, and a central composite design was employed to determine their optimal levels. The optimal medium was used to perform batch fermentation in a 3-l bioreactor. A maximum of 90.29 g l(-1)  L-lactic acid was obtained from 100 g l(-1) xylose in 120 h. When using corn stove prehydrolysates as substrates, 23.49 g l(-1)  L-lactic acid was obtained in 36 h and the yield was 83.09 %.
authors.affiliation: College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China.
authors.forename: Zhaojuan
authors.initials: Z
authors.lastname: Zheng
authors.forename: Cong
authors.initials: C
authors.lastname: Cai
authors.forename: Ting
authors.initials: T
authors.lastname: Jiang
authors.forename: Mingyue
authors.initials: M
authors.lastname: Zhao
authors.forename: Jia
authors.initials: J
authors.lastname: Ouyang
mesh_terms: D001407:Bacillus / Q000235:genetics* / Q000378:metabolism*; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000379:methods*; D005285:Fermentation; D019344:Lactic Acid / Q000096:biosynthesis*; D008031:Lignin / Q000378:metabolism; D009154:Mutation; D014994:Xylose / Q000378:metabolism*; D003313:Zea mays / Q000737:chemistry
chemical_list: C036909:lignocellulose; D019344:Lactic Acid; D008031:Lignin; D014994:Xylose