초록
The objectives of this study were to select an amylolytic lactic acid bacterium for simultaneous saccharification and fermentation (SSF) of starch to lactic acid and determine the optimum conditions for SSF of cassava starch to produce lactic acid by the selected strain. Lactic acid production from SSF of cassava starch by the selected strain using a batch mode and under a non-sterile condition was also investigated. An isolate MSUL 903 was selected. It was named as Lactobacillus plantarum MSUL 903 according to the result of 16S rRNA gene sequences. The optimum conditions for L. plantarum MSUL 903 in SSF of cassava starch to produce lactic acid were determined to be at an initial pH of 6.5, 6% (w/v) of cassava starch concentration, and urea as an inexpensive nitrogen source. Lactic acid concentration at 10.34g/L was obtained. Lactic acid concentration at 39.70g/L was achieved from SSF of cassava starch under a non-sterile condition. The L. plantarum MSUL 903 has been proven to be an efficient amylolytic lactic acid bacterial strain for SSF of cassava starch to lactic acid.