Isolation and Screening of Laccase-producing Fungi from Sawdust-contaminated Sites in Ado-Odo Ota, Ogun State, Nigeria

Abstract

The environmental imbalance exerted by the continuous release of phenolic substances necessitates a return of polluted sites to natural and safe status. In this study, fungal isolates obtained from sawdust-contaminated soils were screened for laccase production capacities, using tannic acid, as an index to the bio-stimulatory potentials of the sawdust. Soil and sawdust samples collected from wood-processing plants in Morogbo-Agbara (M), Iju (I), and Oja (O) of Ado-Odo/Ota, Ogun State, Nigeria were subjected to physicochemical analysis. The phenolic content estimated using gallic acid calibration curve, showed 0.90%, 0.79% and 0.33% for the soil samples labeled MSL, ISL, OSL, respectively. Phenol content was observed to be 0.63%, 0.91%, and 0.53% for sawdust samples labeled MSD, ISD, OSD, respectively. In the same labeling order, the percentage nitrogen content was 0.77%, 0.38%, and 0.21% for soil; and 0.0025%, 0.0035% and 0.0028% for sawdust; while the percentage carbon was 0.25%, 0.62% and 0.49% for soil samples; and 88.11%, 85.56%, and 88.69% for the sawdust samples. Fungal species of Aspergillus, Penicillium, Candida and Saccharomyces among the ten isolates presented a positive reaction for laccase production by showing a brownish-black coloration. The ability of the fungal isolates to produce laccase makes them useful laccase sources for industrial and environmental applications.