Isolation and Characterization of Bacteria and Fungi Associated With Biodegradation of Municipal Solid Wastes in Abakaliki Metropolis, Nigeria

Abstract

Microorganisms involved in the biodegradation of municipal solid waste (MSW) in Abakaliki dumps were isolated and characterized using standard microbiology technique. Five municipal solid waste dumpsites located within Abakaliki metropolis, Ebonyi State, Nigeria were used for this study. The potential of individual microbial isolate to grow on the MSW was also studied using nutrient broth supplemented with mineral salt media and thereafter five of the best microbial degraders were subjected to a 98 days biodegradation studies using weight loss, change in pH, density change and CO2 evolution as indices of success. The study showed that different dumpsites had different temperature readings, bacterial and fungal load, caused by the volume of waste dumped and the habits of the inhabitants. The bacteria population isolated from the dumpsites included Pseudomonas spp, Bacillus spp, Lactobacillus spp, Streptococcus spp, Staphylococcus spp and Micrococcus spp. Penicillum spp, Mucor spp, Aspergillus spp, Fusarum spp, Saccharomyces spp and Candida spp were the fungal species isolated from the dumpsites. The bacteria with the highest growth rate were Bacillus spp, Pseudomonas spp, while Aspergillus spp, Mucor spp, and Saccharomyces spp recorded the highest growth rate for the fungi isolates. The fungi group proved to be better microbial degraders than the bacteria population as a percent weight loss of 1.11 ± 0.03, 1.04 ± 0.05 and 1.23 ± 0.02 were achieved by Saccharomyces spp, Mucor spp and Aspergillus spp respectively. This was in comparison to the bacteria group, which recorded 0.89 ± 0.04 and 0.87 ± 0.03 percent weight loss by Pseudomonas spp and Bacillus spp. Increases in CO2 evolution was equally recorded by both the fungal and bacterial groups as well as increase in acidity. There was a positive correlation among CO2 evolution, weight loss and density for all the test organisms. However, there was no relationship between pH and CO2 evolution, weight loss and density.