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Efficient production of polymer-grade L-lactic acid from corn stover hydrolyzate by thermophilic Bacillus sp. strain XZL4

Zhangwei Xue13, Limin Wang1, Jiansong Ju3, Bo Yu1*, Ping Xu2 and Yanhe Ma1

Author Affiliations

1 Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China

2 State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China

3 College of Life Science, Hebei Normal University, Shijiazhuang, 050016, China

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SpringerPlus 2012, 1:43  doi:10.1186/2193-1801-1-43

Published: 29 October 2012

Abstract

Lactic acid has been identified as one of the top 30 potential building-block chemicals from biomass. Therefore, the search for cheap raw materials is an objective to reduce the production costs. Efficient polymer-grade L-lactic acid production was achieved in this report by a thermophilic strain Bacillus sp. XZL4 using corn stover hydrolyzate as sole carbon source. High L-lactic acid concentration (81.0 g L-1) was obtained from 162.5 g L-1 concentrated corn stover hydrolyzate (total reducing sugar of 83.0 g L-1) with a volumetric productivity of 1.86 g L-1 h-1 (0–36 h) and a product yield of 0.98 g g-1 total reducing sugars. This is the highest L-lactic acid concentration and yield reported from corn stover hydrolyzate. And the high optical purity of L-lactic acid obtained in this study also indicated that Bacillus sp. XZL4 is a promising polymer-grade L-lactic-acid producer from cellulosic biomass.

Keywords:
L-lactic acid; Thermophilic; Bacillus sp; Corn stover hydrolyzate