Pilot Plant Production of Lactic acid by Lactobacillus casei subsp. casei

The aim of present study, was to scale up the production of L (+) lactic acid from the laboratory to pilot plant using Lactobacillus casei subsp. casei PTCC 1608. Moreover, the minimum inhibitory concentration of the produced lactic acid and sodium lactate against 4 test strains including Staphylococcus aureus PTCC 1113, Microccoccus luteus PTTC 1110, Escherichia coli PTCC 1330 and Listeria monocytogenes PTCC 1304 were evaluated. According to the results, the specific growth rate of each test strain was decreased by lactic acid. The inhibitory effect of the sodium lactate was lower than lactic acid in all of the experiments. The best carbon (glucose, lactose and whey) and nitrogen (corn steep powder) sources were optimized in batch and fed batch system and also pH, temperature and aeration were improved in shake flask incubator, 20 l and 750 l stirred tank reactors (STR). Glucose (80 g/l) supplemented with (50 g/l) whey was found as the best production medium. Productivity and yield of calcium lactate production in laboratory scale were 0.51 g/lh and 0.56%, respectively. Fed batch production of calcium lactate in 20 l bioreactor increased the productivity and yield up to 2.47 and 0.83%. Production and productivity was increased up to 350 g/l and 5.4 g/lh, respectively in scaled up processes by 750 liters bioreactor (STR).