Phenotypic and Molecular Screening of Laccase-producing Bacteria Isolated from Automobile Workshop Soil Samples in Ado-Ekiti

Abstract

This work was carried out to isolate hydrocarbon-degrading bacteria from oil contaminated soil sample in Ado-Ekiti and screen them for laccase production. Soil samples were collected and analyzed using standard microbiological techniques. The isolates were initially screened for hydrocarbon degrading ability on minimal salt medium supplemented with 1% crude oil and incubated for 14days. The isolates were further screened for their ability to produce laccase enzyme using plate screening and molecular techniques. Four of the isolates that gave the best results on tannic-agar plates were selected for PCR amplification of laccase gene using specific primers. The isolates were identified as <i>Lactobacillus sakei, Pseudomonas aeruginosa, Bacillus cereus and Gracilibacter thermotolerans</i> based on 16SrRNA sequencing. The DNA of these bacteria amplified the primer specific for laccase gene with 1300bp, 1400bp, 1600bp and 350bp respectively. For bioremediation to be effective, microorganisms must enzymatically attack the pollutants and convert them to harmless products. Therefore, laccase production potentials in these bacteria make them useful in bioremediation as laccase is known to break heavy phenol containing hydrocarbons. Further work can be done to determine the activity of this enzyme during the degradation of crude oil.