Microbial Degradation Of Crude Oila Comparativestudy
Microbial degradation of crude oil is one of the major practices in natural decontamination process.The specific objectives of the present investigation are isolation, screening and selection of microorganisms, batch shake flask studies on the culture growth and biodegradation of crude oil using some reference microbes which are earlier reported to degrade crude oil efficiently.
Soil samples were collected from areas of the Rumelia desert,south of Iraq.Five microbe species were isolated from the soil.The microbe species belongs to the genus,Acinetobacter calcoaceticus (S1), Pseudomonas aeruginosa (S2), Arthrobacter sps(S3), Pseudomonas pictorum(S4) and Pseudomonas resinovorans(S5).Their ability to biodegrade crude oil was tested as single isolates, initial concentration =200ppm,T=30 OC and pH=7 of incubation in the mineral salts medium, the results showed that the microbe Acinetobacter calcoaceticus (S1) was the best with biodegradation ability reaching 99%,while biodegradation ability for Pseudomonas pictorum(S4) 97%, Arthrobacter sps (S3) 96%, Pseudomonas resinovorans(S5) 94% and Pseudomonas aeruginosa (S2) 92%.Also, the results showed that the time play an important on the biodegradation process, in which the percentage of biodegradation increased with time.
The biokinetic parameters of the microbeswere estimated by fitting the growth data to Monod Kinetic Model. The maximum specific growth (µm) and half saturation constant (Ks) has been determined for each initialconcentration of crude oil. It has been observed that with increase in initial concentration of crude oil the (µm)decreases owing to toxic nature of crude oil. The data generated from this study were analyzed using Microsoft excel and Chi- square of the Statistical Procedure for Social Science version 22.0 (SPSS, Chicago, IL, USA).