Browsing by Author "Obayori, O. S."
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Item Biodegradation of p-Chloroaniline by Bacteria Isolated from Contaminated Sites(2010) Fashola, M. O.; Obayori, O. S.; Omotayo, A. E.; Adebusoye, S. A.; Amund, Olukayode O.Enrichment of water from a contaminated site in a textile industry in Ikeja resulted in the isolation of two bacteria belonging to the genera Alcaligenes and Cellulomonas. These bacteria were able to mineralize para-chloroaniline (p-chloroaniline). Time course degradation of p-chloroaniline using pure cultures of these organisms showed that p-chloroaniline supported the growth of these isolates. An initial increase in cell densities of 7.50-9.46 cfu/mL was recorded from day 0-9th day for Cellulomonas sp. while for Alcaligenes denitrificans it was 7.20-9.40 cfu/mL. After day 9, a decrease in population occurred, indicating non-availability of nutrients or toxicity of the medium. Simultaneously, a decrease in the pH, indicative of increased acidity of the medium, was also observed from the first day. The result of the GC analysis of the pure isolates on p-chloroaniline shows that 86.5% of the p-chloroaniline was degraded by the Cellulomonas sp. while 81.2% was degraded by the A. denitrificans in 30 days. These bacterial isolates utilized other hydrocarbons such as pyrene, anthracene, crude oil and chlorobenzoates as sole source of carbon and energy but not phenanthrene, naphthalene and biphenyl. The two isolates tolerated NaCl concentration of up to 5%.Item DEGRADATION OF PYRENE IN SOIL AND IN VITRO BY A BACILLUS LENTUS STRAIN ISOLATED FROM AN ASPHALT PLANT SOIL SITE IN LAGOS, NIGERIA(Ife Journal of Science, 2017-05-28) Obayori, O. S.; Emelogu, C.; Salam, Lateef B.A bacterium isolated from an asphalt plant soil and identified as a strain of Bacillus lentus was tested in vitro and in sterilized and native soils for ability to survive and sustain pyrene degradation over a period of 63 days. The -1 exponential growth rate in vitro was 0.049 d and the doubling time 2.65 d. In the control flask without pyrene, organism density remained virtually constant. In sterilized soil seeded with Bacillus lentus LP32 pyrene concentration declined from 335.0 mg/kg to 8.56 mg/kg at the rate of 10.88 mg/kg/day and half-life of 5.67 days. Similarly, in the native soil seeded with organism there was a decline from 305.2 mg/kg to 8.58 mg/kg in 30 days at the rate of 9.89 mg/kg/day and half-life 5.82. The percentage pyrene degraded in both sterilized and native soils were similar, at 97.45% and 97.19% respectively. This study demonstrated the potential of Bacillus lentus LP32 to serve as seed for enhanced bioremediation of pyrene polluted soil.Item Degradation of spiked pyrene and non-pyrene hydrocarbons in soil microcosms by Pseudomonas species isolated from petroleum polluted soils(Taylor & Francis Group, 2013-01-24) Obayori, O. S.; Ilori, Matthew O.; Amund, Olukayode O.The abilities of three Pseudomonads, Pseudomonas sp. strain LP1, Pseudomonas aeruginosa LP5 and P. aeruginosa LP6 to survive and enhance the degradation of pyrene and non-pyrene hydrocarbons in soil were tested in field-moist microcosms. All three organisms were able to survive and maintain high densities > × 107 in soil. In sterilized soils inoculated with bacterial isolates, 37.34%, 50.30%, and 42.21% were degraded by LP1, LP5, and LP6, respectively. The rates of pyrene degradation in soil microcosms were 0.046, 0.041, and 0.061 mg kg−1 h−1 for LP1, LP5, and LP6, respectively. A mixture of the three isolated degraded 7.73% was degraded in sterilized soil and 87.65% in native unsterilized soil (NS). The isolates also degraded non-pyrene hydrocarbon in the soils by more than 80%. The potentials these pseudomonads isolates for use as seed for bioremediation was successfully demonstrated.Item Effects of cadmium perturbation on the microbial community structure and heavy metal resistome of a tropical agricultural soil(Springer Open, 2020) Salami, Lateef B.; Oluwafemi, S.; Obayori, O. S.; Ilori, Mathew O.; Amund, Olukayode O.The effects of cadmium (Cd) contamination on the microbial community structure, soil physicochemistry and heavy metal resistome of a tropical agricultural soil were evaluated in field-moist soil microcosms. A Cd-contaminated agricultural soil (SL5) and an untreated control (SL4) were compared over a period of 5 weeks. Analysis of the physicochemical properties and heavy metals content of the two microcosms revealed a statistically significant decrease in value of the soil physicochemical parameters (P < 0.05) and concentration of heavy metals (Cd, Pb, Cr, Zn, Fe, Cu, Se) content of the agricultural soil in SL5 microcosm. Illumina shotgun sequencing of the DNA extracted from the two microcosms showed the predominance of the phyla, classes, genera and species of Proteobacteria (37.38%), Actinobacteria (35.02%), Prevotella (6.93%), and Conexibacter woesei (8.93%) in SL4, and Proteobacteria (50.50%), Alphaproteobacteria (22.28%), Methylobacterium (9.14%), and Methylobacterium radiotolerans (12,80%) in SL5, respectively. Statistically significant (P < 0.05) difference between the metagenomes was observed at genus and species delineations. Functional annotation of the two metagenomes revealed diverse heavy metal resistome for the uptake, transport, efflux and detoxification of various heavy metals. It also revealed the exclusive detection in SL5 metagenome of members of RND (resistance nodulation division) protein czcCBA efflux system (czcA, czrA, czrB), CDF (cation diffusion facilitator) transporters (czcD), and genes for enzymes that protect the microbial cells against cadmium stress (sodA, sodB, ahpC). The results obtained in this study showed that Cd contamination significantly affects the soil microbial community structure and function, modifies the heavy metal resistome, alters the soil physicochemistry and results in massive loss of some autochthonous members of the community not adapted to the Cd stress.