Abstract

*Phatake Y. B. and Dharmadhikari S.M.

ABSTRACT

The nutrients require for the growth of the microorganisms is mainly classified as macro nutrients like carbon, nitrogen etc. and micronutrients like iron, calcium etc. The macro nutrients seriously affect growth of the microorganism and yield of the secondary metabolite. Light play important role in the life of animal and plant but microorganisms also show morphological and behavioral changes in presence of different wavelength of the light. So it is necessary to optimize the production process with respect to growth condition and nutrient level to get maximum yield of the product. In this study effect of different physical parameters including light on prodigiosin production was determined and process were further optimized by using classical approach. The study reveal the effect of pH of the medium, time of incubation, temperature of incubation, speed of agitation and different wavelength of light on the red pigment prodigiosin production and on the yield of biomass. As well as stability of produced pigment to the pH. Maximum yield of pigment was obtained in unit/ cell when producer organisms were inoculated in peanut broth of pH 7, incubated at 100rpm in 28ºC temperature for 72hrs. In this study effect of spectrum of light on pigment and biomass production was also determined. Maximum pigment production in unit/ cell was observed when inoculated broth were subjected to white light followed by yellow light and blue light. The incubation in red and green light reduces the yield of pigment but they did not completely inhibit the synthesis of it. Increased pigment production was observed in total white light as compared to the flasks completely exposed to darkness. The visual comparison of the extracted pigment exhibited varied shades of color to different wavelengths of light. Broth exposed to white light incubation yielded a deep red colored pigment whereas yellow light incubation yielded a light red to orange colored pigment. The yield of biomass also changes according to pigment yield, white, blue and yellow light give high yield of biomass, whereas red light and green light reduced the cell growth. The stability of the pigment to pH was also determined. At extremely acidic pH, the red colour pigment appeared as pink (1 to 5).While in highly basic condition, the pigment was almost decolorized (9 to 13).