| dc.description.abstract | Accumulation of solid waste as a result of urbanization, industrialization and the
increasing human population is one of the biggest problems affecting the globe today.
The conventional methods used for disposal of solid waste create even more
environmental problems; hence, there is need for sustainable alternatives of mitigating
solid waste pollution. The aim of this study was to isolate and identify potential useful
microorganisms that are able to degrade and utilize diverse organic and inorganic
materials from Mwakirunge dumpsite-Mombasa. A total of 16 soil samples were
collected using a randomized block design at Mwakirunge dumpsite. The samples were
inoculated in an enriched basal media containing mixed municipal solid waste and
incubated at 37°C for 21 days. A total of 20 fungal and 46 bacterial isolates were
recovered. Microbial identification was done using standard morphological,
biochemical and molecular approaches. Pure genomic DNA was isolated from the pure
recovered microbial isolates using organic DNA isolation methods. PCR amplification
was conducted using universal prokaryotic primers (27F and 1492R) for bacteria and
(ITSI and ITS4) for fungal isolates. Sequencing of the purified PCR products was done at
Inqaba Biotech (S.A). Evolutionary analysis of the sequences obtained was done using
BLASTn algorithm. Evolutionary analysis of the 16S rRNA gene sequences grouped the
bacterial isolates into three (3) phyla; Actinobacteria, Firmicutes and Proteobacteria that
included members affiliated to the genera Bacilli, Pseudomonas, Brevibacilli,
Microbacterium, Ochrobactrum, Paenibacillus, Staphylococcus, Isoptericola and Streptomyces.
Phylogenetic analysis of the ITS gene sequences grouped fungal isolates into the
phylum Ascomycota with members from the genus Aspergillus. The ability of the
isolated microbes to secrete useful extracellular enzymes was tested on media
supplemented with tween 20, tween 80, carboxy methyl cellulase (CMC), starch and
gelatin and the results showed a significant level of enzyme production by the isolates
(p<0.05). Bacillus cereus (MZ571899) exhibited the highest esterase activity; Streptomyces
thermocarboxydus (MZ5718820) exhibited the highest lipase activity, Bacillus subtilis
(MZ571887) exhibited the highest amylase activity, Bacillus licheniformis (MZ571888)
exhibited the highest cellulase activity while Pseudomonas stutzeri (MZ571900) exhibited
the highest gelatinase activity. This study confirms that diverse soil microorganisms
from the dumpsite have potential of waste degradation. These microbes together with
their enzymes can be further studied to improve their biodegradation potential by
genetic engineering. The potential useful isolates and enzymes screened from this study
can also be produced in large quantities for industrial and other biotechnological
applications. Three (3) nearly novel bacterial isolates B4S2 b (MZ571886), B3S1
(MZ571907) and B3S4 B (MZ571915) and one fungal isolate B2S2 a1(MZ569413) were
isolated which could further be characterized using a polyphasic approach. | en_US |
