ASSESSMENT OF MICROORGANISMS ISOLATED FROM SELECTED WASTE DUMPSITES IN ONDO STATE FOR ENZYMES PRODUCTION AND WASTE DEGRADATION

Abstract

This study was designed to assess the microbial diversity and biodegradative ability of microorganisms isolated from selected solid waste dumpsites in Ondo State, Nigeria. Findings in this study revealed the effect of wastes on the microbiological and physicochemical qualities of the receiving environment and its potential impact on public health in Ondo State. The soil samples were collected with soil auger into clean black polythene bags from major towns in Ondo State, which include Akure, Ondo, Idanre, Owo, Okitipupa, Ore and Ikare, for microbial and physiochemical analyses using standard techniques. The isolates were subjected to molecular identification using standard molecular methods DNA isolation, PCR amplification (using 16s forward and reverse primers; universal for bacterial identification) and sequencing of the 16S rRNA gene. All the microbial isolates were screened quantitatively for the production of amylase, lipase and protease enzymes. The findings of the microbiological analysis showed the mean values of the total heterotrophic bacterial counts which ranged from 1.00 × 106 ± 2.64 cfu/g to 9.67 × 106 ± 0.33 cfu/g and mean values of the total fungal counts ranging from 1.00 × 104 ± 0.01 cfu/g to 7.33 × 104 ± 0.21 cfu/g. The physicochemical properties of the dump soils which were as pH, NO3, organic matter (%), Na, K and exchangeable acidity were found to be 5.93 - 9.05, 5.20 - 11.90 meg/kg, 12.76 - 42.53%, 4.30 - 12.44 meg/100g, 1.90 - 19.46 meq/100g and 7.04 - 26.64 meq/100g respectively. Heavy metals from the dump sites were found to be Fe, Mn, Cd, Cu, and Pb was 32.20, 17.93, 4.96, 5.29 and 6.85 ppm respectively. The microorganisms isolated from the dumpsites included nine bacterial genera and five fungal genera. It was observed most of the samples amplified at about 1500 bp on Agarose gel electrophoresis. The study revealed the specific bacterial strains isolated which included Alcaligenes aquatilis, A. faecalis strain WM184, A. faecalis, Bacillus cereus, B. licheniformis, B. subtilis, B. tequilensis, Escherichia coli, Micrococcus luteus, Ochrobacterium oryzae, Proteus mirabilis, Pseudomonas aeruginosa, P. putida, Serratia marcescens and Staphylococcus aureus. It was observed in this study that Bacillus cereus, B. licheniformis, B. subtilis and Pseudomonas putida isolates were the highest enzyme producers recorded while the highest enzyme producing fungal isolates recorded from this study were Aspergillus fumigatus, A. niger and Penicillium chyrsogenum. The microbial isolates with high potential of enzyme activity were selected for the preparation of microbial consortium for waste degradation. Based on the findings obtained from this study, both bacterial and fungal consortia are efficient and effective in solid waste degradation which could be a good and cheap source of useful industrial enzymes for the degradation of the wastes.