Multi-objective process optimization and integration for the sequential and increased production of biomass, lipase and endospores of a probiotic bacterium

The objective of this study was to substantially enhance the yields of lipase, biomass and spores from a sporogenous probiotic bacterium, Bacillus coagulans RK-02 by multivariate response surface modeling and genetic algorithm based optimization. The effect of temperature, agitation and aeration on time course of growth, lipase formation and sporulation of individual batch cultivation were also studied. The optimum conditions for three responses were found to be different from each other. Comparatively lower temperature and higher agitation and aeration were needed for biomass and lipase production than that for maximizing sporulation rate. In the final validation experiment, three different optimal conditions for maximizing each of these responses, namely biomass, lipase and spore yields, in a stage wise manner were maintained respectively. This strategy produced 6.25 g L−1 biomass, 6 × 1012 spores per gram of biomass, and maximum of 13.46 IU lipase. Such high yield of biomass, lipase and spore from batch cultivation is first ever to be reported.