Isolation and Genetic Identification of Lipase Producing Bacteria from Oil-Contaminated Sites

Lipase-producing bacteria can be isolated from various environments, including industrial and agricultural waste, vegetable oils, dairy factories, and oil-contaminated soil. Lipase is the third most important enzyme in biotechnology due to its broad catalytic properties and ability to function in heterogeneous media. The current study aims to isolate, screen, and determine the prevalence of lipase-producing bacteria from various oil-contaminated soils in Basrah province, Iraq. Eleven soil samples and five water samples were collected from various oil-contaminated sites. Identification of lipase-producing bacteria was performed using the 16S rDNA sequencing technique. A total of fifty-one lipase-producing bacterial isolates were identified. Seven isolates exhibited high efficiency in lipase enzyme production, including A5, A1, A3, J3, A4, A2, and G3, with lipase activity values of 49 U.mL-1, 28 U.mL-1, 24 U.mL-1, 23 U.mL-1, 23 U.mL-1, 20 U.mL-1, and 20 U.mL-1, respectively. The isolate A5 was the most promising, exhibiting the highest activity at 49 U.mL-1. Based on the sequencing of the 16S rDNA gene, these seven isolates were identified as Bacillus subtilis strain QD517, Bacillus velezensis strain Bac104, Bacillus subtilis strain PK9, Enterobacter cloacae strain YY-2, Bacillus cereus strain RB1, Lysinibacillus xylanilyticus strain D, and Brevibacillus borstelensis strain LDH-b. Seven lipase-producing bacterial isolates were characterized as new bacterial strains, and their sequences were registered in the NCBI GenBank database. The production of large quantities of the lipase enzyme requires optimization of culture conditions using various factors to enable applications in multiple fields.