Degradation of Petroleum Sludge in Soil by Bacterial-Fungal Co-Culture in Presence of Organic and Inorganic Stimulants

Abstract

A microcosmic study was carried out for degradation of petroleum sludge [4% (w/w) in soil] in presence of constructed microbial consortium of three bacterial strains i.e., Pseudomonas sp. BP10, Acinetobacter sp. PSM11 and Rhodococcus sp. NJ2 and two fungal strains Panicillium oxalicum PS10 and Curvularia verruculosa PS8, isolated from different petroleum hydrocarbon contaminated sites) supplemented with vermicompost and inorganic fertilizer as biostimulants. After six months of incubation, the maximum degradation of TPH from petroleum sludge was recorded as high as 80% in the presence of combination of inorganic and organic fertilizer and microbial consortium while only 33% degradation was attributed by native organisms and abiotic factors. Enhancement (%) in degradation rate of TPH due to addition of vermicompost, inorganic fertilizer and microbial consortium in separation and combination was recorded as 57%, 13%, 35% and 139%, respectively. Besides the enhancement in specific growth rate of soil microbes due to addition of nutrient, bioaugmentation of this constructed microbial consortium also boost the total bacterial and fungal strains present in petroleum sludge contaminated soil. Catabolic enzymes played an important role in degradation and maximum induction of enzymes likes catechol 1, 2 dioxygenase, catechol 2, 3 dioxygenase, catalase, laccase and dehydrogenase activity were recorded 223.89 μ mol g-1, 323.83 μ mol g-1, 0.714 μ mol H2O2 g-1, 0.623 μ mol g-1 and 3.4 μg g-1 h-1, respectively.