title: L-Lactic acid production by combined utilization of agricultural bioresources as renewable and economical substrates through batch and repeated-batch fermentation of Enterococcus faecalis RKY1.
abstract: Enterococcus faecalis RKY1 was used to produce l-lactic acid from hydrol, soybean curd residues (SCR), and malt. Hydrol was efficiently metabolized to l-lactic acid with optical purity of >97.5%, though hydrol contained mixed sugars such as glucose, maltose, maltotriose, and maltodextrin. Combined utilization of hydrol, SCR, and malt was enough to sustain lactic acid fermentation by E. faecalis RKY1. In order to reduce the amount of nitrogen sources and product inhibition, cell-recycle repeated-batch fermentation was employed, where a high cell mass (26.3g/L) was obtained. Lactic acid productivity was improved by removal of lactic acid from fermentation broth by membrane filtration and by linearly increased cell density. When the total of 10 repeated-batch fermentations were carried out using 100g/L hydrol, 150g/L SCR hydrolyzate, and 20g/L malt hydrolyzate as the main nutrients, lactic acid productivity was increased significantly from 3.20g/L/h to 6.37g/L/h.
authors.affiliation: Department of Microbiology, Yogi Vemana University, Kadapa, AP 516003, India.
authors.forename: Lebaka Veeranjaneya
authors.initials: LV
authors.lastname: Reddy
authors.affiliation: Brain Korea 21 Center for Green Food & Food Materials, Department of Food Science and Technology, and Bio-energy Research Center, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Biohelix Co., Naju, Jeonnam 58210, Republic of Korea.
authors.forename: Jong-Sun
authors.initials: JS
authors.lastname: Yun
authors.affiliation: Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Hwa-Won
authors.initials: HW
authors.lastname: Ryu
authors.affiliation: Department of Food Science and Technology, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea. Electronic address: yjwee@ynu.ac.kr.
authors.forename: Young-Jung
authors.initials: YJ
authors.lastname: Wee
mesh_terms: D000383:Agriculture; D019149:Bioreactors; D050260:Carbohydrate Metabolism; D013293:Enterococcus faecalis / Q000378:metabolism*; D005285:Fermentation; D019344:Lactic Acid / Q000096:biosynthesis*; D009584:Nitrogen / Q000378:metabolism
chemical_list: D019344:Lactic Acid; D009584:Nitrogen
keywords: Hydrol; Lactic acid; Malt; Repeated-batch; Soybean curd residues