Optimization of Biodegradation of Long Chain n-Alkanes by Rhodococcus sp. Moj-3449 Using Response Surface Methodology

Abstract

Oil spills and subsequent pollution of marine ecosystems are associated with oil exploitation. The ultimate fate of unrecoverable portion of spilled oil is biodegradation by microorganisms. Rhodococcus sp. Moj-3449 has proven ability of growth on aliphatic hydrocarbons. In this study Response Surface Methodology was employed to optimize the biodegradability of Moj-3449 by changing salinity, pH, temperature and n-C16 concentration. The duplicate experiments conducted were based on a 5-levels rotatable and orthogonal central composite design (CCD) done in 2 separate blocks. The effect of each factor and their interactions on the biodegradation of n-C16 revealed that the optimal conditions for the biodegradation are 0 % salinity at pH= 6.97, T=28°C and 52.98 % wt/V n-C16 concentration. Under these conditions, the maximum biodegraded amount was predicted at 45.52 % wt/V out of 52.98 % wt/V. The experimentally obtained biodegradation amount at the optimum condition was 44.27 ±0.07 % wt/V. The ability of the strain to effectively break down long-chain n-alkanes at concentration up to 55 % wt/V shows at that this strain is an outstanding candidate for industrial bioremediation of crude oil spills in marine environment.