Research of surfactin and polysaccharide production from Bacillus subtilis in whey medium

The aim of this research was to investigate production of polysaccahride and surfactin by Bacillus subtilis ATCC 6633 in whey medium. One day cultured B. subtilis (9.1 log/ml) was inoculated to 10, 15 or 20% of 100 ml whey powder solutions. Inoculated whey powder solutions (WPS) were incubated at 30°C for 72 hours. Viscosity, pH, the number of vegetative cell and spores and the amount of polysaccharide and surfactin were determined at 0, 24th, 48th or 72nd hours of incubation. Polysaccharide amount was measured according to phenol-sulphric acide method. Surfactin was measured by HPLC. For prepearing standart curve gellan standarts was used. The results indicated that pH of WPS was decreased from 6.8 to 5.2 in 24 hours and pH was 4.99 at the end of the incubation (72 h). Viscosity of 10% and 20% WPS were increased 1.27 and 1.10 times at 72 hours, respectively. The number of B. subtilis increased from 9.09 to 10.54 log/ml in 10%, 9.82 log/ml in 15%, 9.38 log/ml in 20% WPS during 72 hours. Among 48-72 hours in %10 whey solution the amount of microorganisms were decreased from 11.62 log to 10.54 log and spore formation were increased from 3.91 log to 4.72 log. Moreover, at the end of 72 h fermentation, the amount of polysaccharide produced by B. subtilis was determined as 394.6 ppm, 412 ppm and 422.5 ppm in 10, 15, 20% WPS, respectively. In this study B. subtilis ATCC 6633 could not produce surfactin in 10%, 15% and 20% WPS medium. As a result, the result of this study showed that WPS is not useful for surfactin production, but could be used for fermentation base of B. subtilis to produce polysaccahride.