5.87 log CFU/mL which produced lactic acid concentration at only 20.29 g/L. These results could infer a decrease in cell activity as reported by [13]. Therefore, to improve lactic acid production efficiency in the repeated-batch and SSF of SCW by L. plantarum MSUL 702, cell immobilization should be studied to increase the initial cell concentration in the subsequent batches. In addition, further study in the use of lactic acid bacterial cells obtained from the drainage of fermentation process as probiotics in animal feed is recommended for environmental friendly production of lactic acid.
3.2. Treatment of SCW in the Repeated-Batch and SSF
The repeated-batch and SSF by L. plantarum MSUL 702 showed a high performance in treating the SCW (Fig. 3). In the 48 h of the second batch fermentation, the COD and TKN concentrations of the SCW were 872.9 mg/L and 2.1 mg/L (Data not shown), respectively, which resulted in the highest COD and TKN removal efficiencies at 98% and 85%, respectively.