Screening for Lipase Enzyme Producing Potentials of Bacillus Species Isolated from Different Automobile Workshops in Anambra State

Abstract

Lipases are versatile biocatalysts and are used in different bioconversion reactions. Microbial lipases are currently attracting a great amount of attention due to the rapid advancement of enzyme technology and its practical application in a variety of industrial processes. The aim of the present study was to screen for lipase enzyme producing potentials of Bacillus species isolated different automobile workshops in Anambra State. In study, soil samples were collected on six different locations with history of oil contamination namely Awka, Nnewi and Onitsha representing the three senatorial zones of Anambra State. Fourteen bacilli strains were isolated from oil contaminated soil samples using Nutrient Agar after heat treated at 80 °C for 15 min prior to serial dilution. The result showed that Onitsha sampling location point B had the highest lipase bacterial count of 23.90 X 10⁴ CFU/g while Awka sampling location point A had the least count of 1.80 X 10⁴ CFU/g, respectively. Tributylin phenol red test was carried out to determine primary lipase activity and subsequent secondary lipase activity was determined using Basal medium with tributyrin (1%). The results revealed that the crude enzyme extracts of three strains AWK1, NW1 and ON3 out of 14 lipolytic bacterial strains had the highest protein content and enzyme activities of 1.29, 1.40, 1.77 mg/mL and 39.18, 40.59, 28.80 U/mL, respectively and applied for further practical applications. These selected bacterial strains were later characterized and identified physiologically and found to be Bacillus sp. AWK1, Bacillus thuringiensis NW1 and Bacillus tropicus ON2 using Bergey’s Manual for Determinative Bacteriology, respectively. The isolation and lipase activities of these strains suggest that the automobile workshops soil samples are great reservoirs lipase producers.