Browsing by Author "Okpuzor, Joy"
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Item Growth and biosurfactant synthesis by Nigerian hydrocarbon-degrading estuarine bacteria(http://creativecommons. org/licenses/by/3.0, 2008-12) Adebusoye, Sunday A.; Amund, Olukayode O.; Ilori, Matthew O.; Domeih, Dupe O.; Okpuzor, JoyThe ability of microorganisms to degrade petroleum hydrocarbons is important for finding an environmentally-friendly method to restoring contaminated environmental matrices. Screening of hydrocarbon utilizing and biosurfactant-producing abilities of organisms from an estuarine ecosystem in Nigeria, Africa, resulted in the isolation of five microbial strains identified as Corynebacterium sp. DDVl, Flavobacterium sp. DDV2, Micrococcus roseus DDV3,Pseudomonas aeruginosa DDV4 and Saccharomyces cerevisae DDV5. These isolates grew readily on several hydrocarbons including hexadecane, dodecane, crude oil and petroleum fractions. Axenic cultures of the organisms utilized diesel oil (1.0%v/v) with generation times that ranged significantly (t-test, P < 0.05) between 3.25 and 3.88 day, with concomitant production of biosurfactants. Kinetics of growth indicates that biosurfactant synthesis occurred predominantly during exponential growth phase, suggesting that the bioactive molecules are primary metabolites. Strains DDV1 and DDV4 were evidently the most metabolically active in terms of substrate utilization and biosurfactant synthesis compared to other strains with respective emulsification index of 63 and 78%. Preliminary biochemical characterization indicates that the biosurfactants are heteropolymers consisting of lipid, protein and carbohydrate moieties. The hydrocarbon catabolic properties coupled with biosurfactant-producing capacibilities is an asset that could be exploited for cleanup of oil-contaminated matrices and also in food and cosmetic industries.Item Physico-chemical properties of municipal refuse in Lagos metropolis and cellulolytic activities of resident microorganisms associated with organic matter degradation(Ivyspring International Publisher, 2010) Ogunyemi, Adewale; Amund, Olukayode O.; Okpuzor, Joy; Adeiga, Adesina; Nneoma, Idika; Omowunmi, A.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.