In vitro studies on suitability of various natural and synthetic substrates for growth, cell biomass and crystal protein production of bacillus thuringiensis isolate pkkvk 9

Ramamourti, A., Tholkappian, p., and Jayachandran, S

The gram positive endospore forming Bacillus thuringiensis bacterium producing pesticidal crystal proteins known for encountering the insect pests is considered to be environmentally safe. Several methods used to prawl more number of infective colonies, they may vary on production techniques using solid substrates by the process Media Optimization. The low cost and ease of preparation of agro-industry based wastes and organic substrates having carbon and nitrogen sources in addition to organic basal salts supporting Bacillus thuringiensis growth profusely. Utilizing certain organic raw materials and synthetic substrates optimally to increase the cell biomass and crystal protein production and iniquitous growth of indigenously isolated Bacillus thuringiensis isolate PKKVK 9 in Puducherry, Molasses favoured the growth of Bacillus thuringiensis at maximum (OD = 2.072) which was followed by Cassava Tippi (OD = 1.978), Luria Bertani Broth (OD = 1.745), Lignite (OD = 0.242) and the minimum growth was observed in Whey (OD = 0.228). Maximum biomass production of Bacillus thuringiensis was found in the substrate Luria Bertani broth (2.714 g/100ml) which was closer to the cell biomass production yielded by the substrate Molasses (2.619 g/100ml). The minimum cell biomass production was found in Whey (0.106 g/100ml). Of the substrate concentrations, 1% concentration was found to be optimum for the growth of Bacillus thuringiensis and also for maximum cell biomass and crystal protein production. The pH of the substrates played a crucial role in the growth as well as production of crystal protein by Bacillus thuringiensis effectively and among pH levels, pH 7 was found to be the optimum. Similarly, the substrate Molasses excelled the production of both cell protein (132.85µg/ml) and crystallaceous protein (32.63µg/ml) very well and the least cell and crystallaceous proteins levels (27.83 and 6.98µg/ml) were found with the substrate Whey. However, cell & crystallaceous proteins produced by synthetic substrate Luria Bertani Broth were nearing to Molasses while other substrates like Fishmeal, Cellulose, Soya peptone, Glucose, Sucrose also aided well in the production of cell and crystallaceous protein when compared to control