Authors :
Rina Rani Ray,
Author Address :
Post Graduate Department of Zoology, Bethune College, 181, Bidhan Sarani, Kolkata: 700 006, India, Email : raypumicro@gmail.com
Abstract :
The production of polygalacturonase (PG ase) by an yeast strain, Saccharomyces cerevisae in submerged fermentation (SmF) of various citrus wastes was optimized. The effects of the fermentation parameters namely initial pH, temperature and cultivation time on enzyme production were studied using both pure pectin and citrus wastes as the sole carbon source at a time method. It was found that although dried citrus pulps did not show sufficient inducing activity, citrus peels were proved to be competent carbon source for extra cellular polygalacturonase production. Although pure pectin at a concentration of 0.5% (w/v) was found to be most effective for enzyme production, higher concentration of lemon peel was proved to be better than pure substrate. The optimum pH for enzyme production was found to depend on the type of carbon source used as for orange peel, pure pectin and lemon peel supplemented cultures, the preferred pH s were 4, 6 and 7 respectively. Highest production was achieved at a temperature of 27°C. The enzyme production kinetics indicated that the strain took a longer time (5 days) to hydrolyse waste pectins for enzyme production than the pure substrate (3 days).
Keywords :
Citrus wastes, polygalacturonase, Saccharomyces cerevisae, submerged fermentation and yeast.