Efficient production of l-lactic acid from corncob molasses, a waste by-product in xylitol production, by a newly isolated xylose utilizing Bacillus sp. strain

Abstract

Lignocellulosic biomass-derived sugars are considered nowadays to be an economically attractive carbohydrate feedstock for large-scale fermentations of bulk chemicals such as lactic acid. In the present study, corncob molasses containing a high content of xylose, which is one of the lignocellulosic biomasses and a waste by-product from xylitol production, was used for l-lactic acid production via a newly isolated xylose utilizing Bacillus sp. strain XZL9. Bacillus sp. strain XZL9 can utilize the mixture of sugars including xylose, arabinose, and glucose in corncob molasses for l-lactic acid production. High concentration of l-lactic acid (74.7 g l −1) was obtained from corncob molasses (initial total sugars of 91.4 g l −1) in fed-batch fermentation. This study provides an encouraging means of producing l-lactic acid from lignocellulosic resource such as the low-cost corncob molasses.