Biodegradation of hydrocarbon by bacteria isolated from crude oil contaminated soil

Crude oil contaminated soil has posed major environmental problems in recent years. Hence, this work was designed to evaluate the potential of microorganisms isolated from crude oil contaminate soil, to degrade hydrocarbon. Samples of crude oil contaminated soil were collected from Warri Refining and petrochemical Company in Delta State and characterized using standard microbiological procedure. Isolates were assayed for their ability to degrade hydrocarbon using mineral salt medium containing crude oil as source of carbon. Soil samples were treated as follows: A – untreated/control soil plus sterile crude oil, B – untreated soil plus crude oil and carrier, C – treated soil (with Enterobacter aerogenes) plus crude oil and carrier, D – treated soil (with Actinomycetes) plus crude oil and carrier, E – treated soil (with Enterobacter aerogenes and Actinomycetes) plus crude oil and carrier. After ۱۴ days treatment, A had no growth while B, C, D and E had bacterial count of ۲.۶ x۱۰۴ cfu/g, ۷.۶۸x۱۰۱۱, ۱.۴۲x۱۰۱۲ and ۱.۹۶x۱۰۲ cfu/g respectively. At the end of ۲۸ days period, A, B, C, D and E had count of ۱.۲ x ۱۰۳cfu/g, ۵.۲۲ x ۱۰۱۱cfu/g, ۹.۳۰ x ۱۰۱۴cfu/g, ۱.۷۹ x۱۰۱۷cfu/g and ۲.۵۲ x.۱۰۱۹ cfu/g respectively. Serratia marcescens, Actinomycetes and Enterobacter aerogenes showed crude oil reduction of ۴۴.۳ %, ۷۹.۲۶ % and ۶۱.۶۹ % respectively. The results showed that Actinomycetes had the highest reduction rate of hydrocarbon content of soil more than other bacterial isolates.

کلیدواژه ها:

Carrier ، Crude oil ، hydrocarbon ، microorganisms ، physicochemical ، soil