Pilot-Scale Lactic Acid Production via Batch Culturing of Lactobacillus sp. RKY2 Using Corn Steep Liquor As a Nitrogen Source

Young-Jung Wee¹, Hyang-Ok Kim², Jong-Sun Yun³ and Hwa-Won Ryu¹*

¹School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea
²Department of Material Chemical and Biochemical Engineering, Chonnam National University, Gwangju 500-757, Republic of Korea
³BioHelix, Noan-myeon, Naju, Jeonnam 520-811, Republic of Korea

Article history:
Received November 30, 2005
Accepted March 22, 2006

Key words:
lactic acid, Lactobacillus, corn steep liquor, fermentation, wood hydrolyzate, pilot-scale

Summary:
In this study, the determination of the efficiency of a pilot-scale fermentation process using corn steep liquor as a nitrogen source was attempted in order to produce lactic acid via batch culturing of Lactobacillus sp. RKY2. Using pure glucose, fermentation efficiency characteristics, such as final lactic acid, cell growth, yield, and productivity were not substantially influenced by the scale-up of the laboratory-scale fermentation from 2.5- to 30- and 300-litre scale fermentations. In all experiments, the content of lactic acid produced increased in a linear fashion with increases in the initial glucose concentration. In the experiments using wood hydrolyzate, both lactic acid productivity and cell growth were decreased as a result of the scaling-up of the fermentation. This might be attributed to the toxic chemicals contained in the wood hydrolyzates. However, in all experiments, lactic acid yields remained higher than 90 % with regard to the amount of glucose consumed. Therefore, lactic acid was successfully produced by the pilot-scale bioreactor scheme adopted in this study.

*Corresponding author:           hwryu@chonnam.ac.kr
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