Physico-chemical properties of municipal refuse in Lagos metropolis and cellulolytic activities of resident microorganisms associated with organic matter degradation

Abstract

This study investigated the activities of micro organisms involved in the degradation of organic matter in solid wastes and their potential to produce cellulolytic enzymes. Soil samples of decomposing waste piles were collected from four designated landfill sites in Lagos metropolis and analyzed for physicochemical properties, toxic heavy metal content and microbial populations. Findings revealed that the moisture content of the soils ranged from 7.6 - 10.0% in all the locations sampled. Ojota-Olusosun site had the highest organic matter content of 10.65%. The highest viable bacterial counts were 28.2 ± 3.0 x 106 cfu/g while fungi were

47.0 ± 4.0 x 104 cfu/g respectively. A similar pattern was observed for phosphate and chloride levels while some heavy metals were also detected in varying and high amounts. There was a significant positive correlation at 5% level between fungal viable counts and phosphate ion while a significant negative correlation was observed for total hydrocarbon. The bacteria associated with the soil samples were identified as Escherichia coli, Bacillus spp, Klebisella spp, Micrococcus spp. and Acinetobacter spp while the resident fungal species were mostly the Aspergillus spp and an isolate identified as Mucor spp. The moulds were found to be capable of utilising lignin and cellulosic substrates for growth and for production of cellulolytic enzymes. Results from this study suggest that such micro organisms could be useful in bioconversion of cellulosic substrates and solid wastes to cellulolytic enzymes for industrial processes.

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Keywords: Solid wastes, Landfills, Heavy metals, Bacteria, Cellulolytic enzymes, Fungi.