Characterization of Lipase Producing Ochrobactrum ciceri SW3 Collected from Untapped Oil Contaminated Soil

Abstract

The study aimed to explore the industrially important oil-based substrates degrading bacteria from untapped oil-contaminated soils, especially bacteria exhibiting potential for bioremediation. A total of 25 samples from five groups of unexplored oil contaminated soil sites (workshop, oil exchange, truck stand, hotels, and generator soil site) were first collected in Faisalabad to investigate. Tween20 (1%) agar plates were used to isolate and screen lipid substrates utilizing bacteria. Total colony-forming units (8.26×107) and the capacity of lipid substrates utilization by bacteria were determined through several lipase zones (434) found in 25 soil samples. Maximum CFUs (1.96×107) and lipase zones (124) around colonies appeared in workshop soil. Bacterial isolate SW3, with largest lipase zone showed maximum growths at optimum pH 6 (4.541±0.06, OD) and lipase activity (11.66±0.3LU/mL), while growth (4.48±0.08, OD), lipase activity (10.58±0.53LU/mL) at optimum temperature 37˚C, was calculated in the presence of 1% olive oil after 48 h of incubation respectively. SW3 showed resistance up to 5% NaCl concentration. The truck stand contaminated soil site was slightly more diverse in lipase-producing bacteria (1.54) compared to the other four sites by Shannon diversity index (H’) analysis. All results were statistically analyzed through ANOVA. Isolate SW3 showed 99% sequence similarity to Ochrobactrum ciceri through 16S rRNA gene analysis. This study is an effort to report the initial screening of indigenous bacteria with degradation potential, especially the SW3 isolate, which works under a wide range of environmental conditions and may be considered in the future to reduce environmental issues.