Probiotic properties in vitro of the L. acidophilus T12.2 (VTCC 12257), were isolated from fermented shrimp were evaluated based on biological characteristics and tolerance under simulated intestinal conditions. In this study, the growth kinetics of the VTCC 12257 strain was studied for high biomass production in a lab and 30 litre bioreactor scale. In case of a lab, the highest biomass was obtained under the culture conditions as SPY medium, at 37oC, pH 6.5, inoculum size of 3% in 32 h; the best sources of carbon and nitrogen were found to be glucose and mixture of peptone and yeast extract; cell dry weight reached 0.59 g/l. During 30 litre bioreactor cultivation, the maximal cell mass obtained at the agitation speed of 50 rpm, and 16-24 h of incubation, was 0.72 g/l in pH-controlled culture and 0.64 g/l in the uncontrolled pH. This is considered as the first step for cell mass production of this probiotic bacterium in the industrial scale.

Keywords: biomass, lab and 30 litre bioreactor scale, L.acidophilus VTCC 12257, probiotic.