Optimization of beta-carotene production by Rhodotorula glutinis DM28 in fermented radish brine.

A face-centered central composite design was applied to optimize a cultivation condition for improved beta-carotene production by Rhodotorula glutinis DM28 in a stirred tank reactor using 30 g/l total soluble solid of fermented radish brine as a sole substrate. The experiments were performed with regression models, where temperature, pH and dissolved oxygen were considered as variables. Results showed that an optimum condition for beta-carotene production of the yeast was at 30 degrees C, pH 6 and 80% dissolved oxygen. Under this condition, the yeast yielded 2.7 g/l biomass and the maximum beta-carotene of 201 microg/l after 24-h fermentation indicating approximately 15% higher than those under an initial condition (2.3g/l and 178 microg/l, respectively).