title: L-Lactic acid production benefits from reduction of environmental osmotic stress through neutralizing agent combination.
abstract: This paper hinged on the combination effect of two different neutralizing agents Ca(OH)2 and NH4OH on the production of L-lactic acid by Lactobacillus paracasei. Present study quantitatively indicated that environmental osmotic pressure (844-1,772 mOsm/kg) exerted minor influence on L-lactic acid production, but a critical level fell on approximately 3,000 mOsm/kg which restricted L-lactic acid production significantly. Once osmotic pressure exceeded 3,600 mOsm/kg, L-lactic acid production ran aground. A new and efficient neutralizing agent-adding strategy was established in this study to procure 2.21-fold enhancement (5.94 g/l/h) relative to previous productivity of L-lactic acid with NH4OH as neutralizing agent via batch cultivation. It was, therefore, speculated that inhibition effect in the late phase of the fermentation might be in large part attributed to the dramatic increase of environmental osmotic stress, other than cumulative effect of lactate concentration itself.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, P.O. Box 329, Shanghai, 200237, People's Republic of China.
authors.forename: Xiwei
authors.initials: X
authors.lastname: Tian
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wang
authors.forename: Ju
authors.initials: J
authors.lastname: Chu
authors.forename: Yingping
authors.initials: Y
authors.lastname: Zhuang
authors.forename: Siliang
authors.initials: S
authors.lastname: Zhang
mesh_terms: D019344:Lactic Acid / Q000096:biosynthesis*; D007778:Lactobacillus / Q000378:metabolism*; D009997:Osmotic Pressure; D013056:Spectrophotometry, Ultraviolet
chemical_list: D019344:Lactic Acid