Characterization and Optimization of Factors Affecting Growth and Pigment Production of Bacterium Isolate Mif41

Abstract

At present, due to the health side effects of chemically synthesized coloring agents, naturally produced coloring agents were favored. From all naturally produced coloring sources, microbial pigments have been given precedence, due to easy manipulation of the microorganisms and optimization of the production processes. The main aim of this article is to report the characteristics and factors affecting growth and pigment production by bacterium isolate Mif41. The soil samples were collected and serially diluted from 10 -1 to 10 -6 and each dilution was plate on the sterilized Glucose, mannitol, Tryptose Yeast extract Agar (GMTYEA) medium and incubated at 28°C under aerobic condition. After 48h of incubation the yellow pigmented bacterium isolate was picked and purified by repeated streaking on GMTYEA and the pure culture was maintained on slant at 4°C. The pure culture of the bacterium isolate was characterized morphologically and biochemically. Both extracellular and intracellular pigments obtained from the bacterium isolate were analyzed by using UV-visible spectrophotometer. Effect of carbon sources, nitrogen sources, medium PH, incubation temperature and effect of salt concentrations on growth and pigment production were evaluated. The morphological and biochemical characterization of the bacterium isolate tentatively suggested as Pseudomonas sp. From the different carbon sources tested fructose favored maximum extracellular and intra cellular pigmentation while sorbitol was found minimal in this respect. All the organic sources of nitrogen stimulated growth and pigmentation while all the inorganic sources of nitrogen were inhibitory for growth and pigmentation. Incubation temperatures of 20-28°C were favored growth and pigmentation while incubation temperature above 30 were highly limiting for growth and pigmentation. Medium PH 8 found to be favorable for growth and pigmentation while acidic and basic pH were limiting for growth and pigmentation. Lower salt concentration was found to favor the growth and pigmentation, while increased concentration were found to be limiting. The results of this study clearly indicated that the bacterium isolate Mif41 is able to produce different colored pigments under different nutritional and environmental conditions suggesting that this bacterium isolate will be considered as a candidate for the industrial production of pigments which will be applied in various industries.