Highly efficient L-lactate production by a thermophilic strain Bacillus sp. NLO1 was demonstrated in this study. Lignocellulosic hydrolyzates containing a high content of glucose, which was prepared from corn stover, was used as substrate for L-lactic acid production. The fermentation was carried out under open condition without sterilization and used NaOH as alkaline neutralizing reagent. In batch fermentation, 56.37 gl(-1) L-lactic acid was obtained from lignocellulosic hydrolyzates which contained the solid residues produced in enzymatic saccharification. In fed-batch fermentation, 75.03 gl(-1) L-lactic acid was obtained from lignocellulosic hydrolyzates supernatant. The yield was 74.5% and the average productivity was 1.04 g l(-1) h(-1). Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.