title: Efficient production of polymer-grade L-lactate by an alkaliphilic Exiguobacterium sp. strain under nonsterile open fermentation conditions.
abstract: In this study, a newly isolated alkaliphile Exiguobacterium sp. strain 8-11-1 was used to produce optically pure L-lactate. With an initial glucose concentration of 80 g/L, a high overall L-lactic acid productivity of 8.15 g/L/h was achieved using NaOH as a neutralizing agent. The fed-batch fermentations were carried out under both sterile and nonsterile conditions. Under the nonsterile condition, 125 g/L L-lactic acid was obtained with a high percent yield and average productivity of 98.33% and 3.79 g/L/h, respectively. These values were consistent with the results from sterile condition. No d-isomers of lactic acid were detected, resulting in an optical purity of 100% in both conditions. The high levels of optically pure L-lactic acid produced by Exiguobacterium sp. 8-11-1, combined with the ease of handling and low costs associated with the open fermentation strategy, provide a novel and potentially important approach for L-lactic acid production in the future.
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Jiang
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Xue
authors.forename: Aiyan
authors.initials: A
authors.lastname: Wang
authors.forename: Limin
authors.initials: L
authors.lastname: Wang
authors.forename: Guimin
authors.initials: G
authors.lastname: Zhang
authors.forename: Qingtao
authors.initials: Q
authors.lastname: Zeng
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D001407:Bacillus / Q000378:metabolism*; D005285:Fermentation; D007773:Lactates / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism*
chemical_list: D007773:Lactates; D011108:Polymers
keywords: Alkaliphile; Exiguobacterium sp.; Open fermentation; l-Lactate