title: Batch and repeated batch production of L (+)-lactic acid by Enterococcus faecalis RKY1 using wood hydrolyzate and corn steep liquor.
abstract: Lactic acid production was investigated for batch and repeated batch cultures of Enterococcus faecalis RKY1, using wood hydrolyzate and corn steep liquor. When wood hydrolyzate (equivalent to 50 g l(-1) glucose) supplemented with 15-60 g l(-1) corn steep liquor was used as a raw material for fermentation, up to 48.6 g l(-1) of lactic acid was produced with, volumetric productivities ranging between 0.8 and 1.4 g l(-1 )h(-1). When a medium containing wood hydrolyzate and 15 g l(-1) corn steep liquor was supplemented with 1.5 g l(-1) yeast extract, we observed 1.9-fold and 1.6-fold increases in lactic acid productivity and cell growth, respectively. In this case, the nitrogen source cost for producing 1 kg lactic acid can be reduced to 23% of that for fermentation from wood hydrolyzate using 15 g l(-1) yeast extract as a single nitrogen source. In addition, lactic acid productivity could be maximized by conducting a cell-recycle repeated batch culture of E. faecalis RKY1. The maximum productivity for this process was determined to be 4.0 g l(-1 )h(-1).
authors.affiliation: School of Biological Sciences and Technology, Chonnam National University, 300 Yongbong-dong, Buk-gu, 500-757, Gwangju, Korea.
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Wee
authors.forename: J-S
authors.initials: JS
authors.lastname: Yun
authors.forename: D
authors.initials: D
authors.lastname: Kim
authors.forename: H-W
authors.initials: HW
authors.lastname: Ryu
mesh_terms: D018533:Biomass; D013293:Enterococcus faecalis / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation; D019344:Lactic Acid / Q000378:metabolism*; D010461:Peptones / Q000378:metabolism; D013237:Stereoisomerism; D014934:Wood; D003313:Zea mays / Q000378:metabolism
chemical_list: D010461:Peptones; D019344:Lactic Acid