Assessment of Petroleum Hydrocarbon Degradability Potential of Bacteria Isolated From Petroleum Oil

Abstract

newlineThis research work was designed to assess petroleum hydrocarbon degradability potential of various bacteria isolated from petroleum oil contaminated sites and enhance the ability of microbes to remove petroleum hydrocarbon contamination from contaminated environment. Total numbers of forty nine bacteria were isolated, in which four bacteria were selected as the most promising having high degradation ability and they are identified as Alcaligenes species, Bacillus methylotrophicus, Enterobactor species and Corynebacterium species. Different parameters like petroleum oil concentration, nitrogen source, nitrogen concentration, pH and temperature were optimized for the optimum growth of selected bacterial cultures. The optimum petroleum oil concentration for isolates Alcaligenes species, Enterobacter species and Corynebacterium species was 4% (v/v) while Bacillus methylotrophicus showed optimum growth at 8% (v/v). Ammonium nitrate was best nitrogen source for isolates of Alcaligenes species, Bacillus methylotrophicus and Corynebacterium species however Enterobacter species showed best growth with sodium nitrate. Nitrogen concentration for the Alcaligenes species, Bacillus methylotrophicus was 0.15 % (w/v) and for Enterobacter species, Corynebacterium species it was 0.2% (w/v). Optimum growth for all the four bacteria was at 6-7 pH and temperature range 30-35ºC. Optimum growth conditions enhance the degradation of petroleum hydrocarbon. Out of these four bacterial isolates, only two Enterobacter species and Corynebacterium species produced biosurfactant while Corynebacterium species showed maximum production. Biosurfactants produced by Corynebacterium species was studied and characterized as 13- Docosenamide (z) that enhanced the oil degradation capacity of other bacterial isolates. The formulation of newlinev newlinebacterial consortium of these isolates showed more effective degradation than pure cultures.The consortium O formulation of four bacteria Alcaligenes species, Bacillus methylotrophicus, Enterobacter sp