OPTIMIZATION OF ENVIRONMENTAL GROWTH PARAMETERS FOR BIODIESEL PRODUCING BACTERIA RHODOCOCCUS OPACUS USING RESPONSE SURFACE METHODOLOGY

Abstract

Back ground: Rising level of carbon dioxide, increasing demands and value of fuel, generation of waste are the key issues of the modern society. Biodiesel is an alternate to standard fossil fuel. Currently, it's primarily made from vegetable oils associated consequently it's an adverse impact on food security. Lipids from oleaginous microorganisms (e.g. microalgae, bacteria, fungi and yeasts) may well be an alternate feedstock for biodiesel production and therefore the growth and lipid accumulation of Rhodococcus opacus was studied under different environmental conditions. Results: The current aim of the study is to utilized Box Behnken Design (BBD) of the response surface methodology, for identifying optimum levels of particular variables. BBD design was performed on oleaginous bacterium, Rhodococcus opacus considering pH, temperature and incubation period as independent variables. Lipid and biomass contents were analyzed as response variables. A second order polynomial model produced a satisfactory results of the experimental data with regard to biomass yield and lipid content % (R2 = 98, 04, 96.96 (P ≤ 0.01). Optimum results of the experiments were 3.82 gL-1 biomass and lipid content 33.55% at optimized conditions pH-7, temperature-300C and incubation time - 72 hrs. Results of predicted and actual response were differing with 2 to 3 % and desirability of model 98%.