Browsing by Author "Ilori, Matthew O."

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    Aerobic Degradation of Di- and Trichlorobenzenes by Two Bacteria isolated from Polluted Tropical Soils.
    (Pergamon, 2007-01-01) Adebusoye, Sunday A.; Picardal, Flynn W.; Ilori, Matthew O.; Amund, Olukayode O.; Fuqua, Clay; Grindle, Nathan
    Two polychlorinated biphenyl (PCBs)-degrading bacteria were isolated by traditional enrichment technique from electrical transformer fluid (Askarel)-contaminated soils in Lagos, Nigeria. They were classified and identified as Enterobacter sp. SA-2 and Pseudomonas sp. SA-6 on the basis of 16S rRNA gene analysis, in addition to standard cultural and biochemical techniques. The strains were able to grow extensively on dichloro- and trichlorobenzenes. Although they failed to grow on tetrachlorobenzenes, monochloro- and dichlorobenzoic acids, they were able to utilize all monochlorobiphenyls, and some dichlorobiphenyls as sole sources of carbon and energy. The effect of incubation with axenic cultures on the degradation of 0.9 mM 1,4-dichlorobenzene, 0.44 mM 1,2,3- and 0.43 mM 1,3,5-trichlorobenzene in mineral salts medium was studied. Approximately, 80–90% of these xenobiotics were degraded in 200 h, concomitant with cell increase of up to three orders of magnitude, while generation times ranged significantly (P < 0.05) from 17–32 h. Catechol 1,2-dioxygenase and catechol 2,3-dioxygenase activities were detected in crude cell-free extracts of cultures pre-grown with benzoate, with the latter enzyme exhibiting a slightly higher activity (0.15–0.17 lmol min1 mg of protein1) with catechol, suggesting that the meta-cleavage pathway is the most readily available catabolic route in the SA strains. The wider substrate specificity of these tropical isolates may help in assessing natural detoxification processes and in designing bioremediation and bioaugmentation methods.
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    Alkaline extracted cyanide from cassava wastewater and its sole induction of chromosomal aberrations on Allium cepa L. root tips
    (Taylor and Francis Online : Environmental Technology, 2021-04) Ogunyemi, Adewale; Abayomi, Akeem A.; Opawale, Rachael O.; Samuel, Titilola A.; Ilori, Matthew O.; Amund, Olukayode O.; Babajide, Alo
    Cassava, a staple crop in Nigeria, processed by numerous factories in rural and sub-urban locations is known to contain some level of cyano compounds. Lack of stringent environmental regulations on management of cassava wastewater (CWW) from cassava processing factories had led to its indiscriminate discharge on the environment. CWW samples were obtained from cassava processing factories from selected states (Lagos (A), Oyo (B), Ogun 1 (C1), Ogun 2 (C2) and Cross River (D)) in Nigeria to determine the cytotoxic and genotoxic effects of extracted cyanide from the wastewaters. The cyanide was hydrolyzed via chemical degradation utilizing 1.25 M NaOH and subsequently titrated using silver nitrate with p-dimethylaminobenzalrhodamine as indicator. Further, in order to explore the potential toxicity of this pollutant present in the effluent, a battery of short-term biological assay (Allium cepa chromosomal aberration test) was used. Bulbs with roots of Allium cepa L. were treated with different concentrations (0.05%, 0.1%, 0.2%, 0.4%, and 0.8%) of CWW, and after 48 h the root tips were processed for cytological studies by the aceto-orcein squash procedure. The results revealed that cyanide concentrations on re-fluxing were in the range of 1.0 mg/L and 1.3 mg/L. All concentrations induced a number of chromosomal aberrations in the root tip cells. The mitotic index decreased significantly (p < 0.05) with increasing concentration. The cytotoxic effects showed strong concentration dependent root growth inhibition with EC50 values of 30, 20, 37, 43 and 22 % for A, B, C1, C2 and D, after 72 h. The findings thus indicate that alkali treatment is very efficient in degrading the cyanide content of CWW and has shown that the combination of physico-chemical analysis along with the sole toxicity assessment could provide valuable information about the sole toxicity of cyanide as a chemical pollutant present in the cassava effluent.
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    Assessment of bacterial degradation of lignocellulosic residues (sawdust) in a tropical estuarine microcosm using improvised floating raft equipment
    (Elsevier, 2015-10-01) Buraimoh, Olanike M.; Ilori, Matthew O.; Amund, Olukayode O.; Michel Jr, Frederick C.; Grewal, Sukhbir K.
    In situ and laboratory studies were carried out to determine the ability of bacterial strains isolated from a tropical lagoon to degrade lignin and carbohydrate components of sawdust, with a view to abating the impact of sawdust pollution on these ecosystem. A floating raft system was designed and fabricated to carry out the in situ biodegradation studies over a period of 24 weeks. Nine bacterial strains identified by 16S rRNA gene sequencing as species of Streptomyces, Bacillus and Paenibacillus isolated from the lagoon were used as seed organisms. In the in situ study, 59.2% of sawdust was depleted at the rate of 1.175 x 10-4 gd-1 cm-3 by the bacterial isolates, whereas the lignin component of the sawdust decreased by up to 82.5% at the rate of 1.80 x 10-5 gd-1 cm-3. The maximum decrease in carbohydrate content was 85% at the rate of 2.192 x 10-7 gd-1 cm-3. In a similar experiment under laboratory conditions, total weight losses ranging from 26 to 51% in the wood residues were observed.
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    Bacteria with dual resistance to elevated concentrations of heavy metals and antibiotics in Nigerian Contaminated Systems.
    (Springer Netherlands, 2010-09-01) Oyetibo, Ganiyu O.; Ilori, Matthew O.; Adebusoye, Sunday A.; Obayori, Oluwafemi S.; Amund, Olukayode O.
    Samples of soil, water, and sediments from industrial estates in Lagos were collected and analyzed for heavy metals and physicochemical composition. Bacteria that are resistant to elevated concentrations of metals (Cd2+, Co2+, Ni2+, Cr6+, and Hg2+) were isolated from the samples, and they were further screened for antibiotic sensitivity. The minimum tolerance concentrations (MTCs) of the isolates with dual resistance to the metals were determined. The physicochemistry of all the samples indicated were heavily polluted. Twenty-two of the 270 bacterial strains isolated showed dual resistances to antibiotics and heavy metals. The MTCs of isolates to the metals were 14 mM for Cd2+, 15 mM for Co2+ and Ni2+, 17 mM for Cr6+, and 10 mM for Hg2+. Five strains (Pseudomonas aeruginosa, Actinomyces turicensis, Acinetobacter junni, Nocardia sp., and Micrococcus sp.) resisted all the 18 antibiotics tested. Whereas Rhodococcus sp. and Micrococcus sp. resisted 15 mM Ni2+, P. aeruginosa resisted 10 mM Co2+. To our knowledge, there has not been any report of bacterial strains resisting such high doses of metals coupled with wide range of antibiotics. Therefore, dual expressions of antibiotics and heavy-metal resistance make the isolates, potential seeds for decommissioning of sites polluted with industrial effluents rich in heavy metals, since the bacteria will be able to withstand in situ antibiosis that may prevail in such ecosystems.
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    Biodegradation of crude oil and phenanthrene by heavy metal resistant Bacillus subtilis isolated from a multi-polluted industrial wastewater creek
    (Elsevier, 2017-05-01) Oyetibo, Ganiyu O.; Chien, Mei-Fang; Ikeda-Ohtsubo, Wakako; Suzuki, Hitoshi; Obayori, Oluwafemi S.; Adebusoye, Sunday A.; Ilori, Matthew O.; Amund, Olukayode O.; Endo, Ginro
    A critical bottleneck associated with bioremediation technology in multi-polluted environments is microbiostasis due to metal toxicity. Autochthonous Bacillus species that would harness a repertory of traits to catabolize hydrocarbons and simultaneously sequester heavy metals (HMs) is invaluable in the environment contaminated with divergent pollutants. Fourteen HM-resistant bacilli from polluted creek were characterized using phenotypic and molecular criteria, and studied for hydrocarbon degradation in chemically defined media amended with Co2+ and Ni2+ (5.0 mmol l−1 each). Phylogenetic analyses revealed distribution of the bacilli into three clades. Two dissimilar strains of Bacillus subtilis (M16K, and M19F) with 19.1% sequence divergence, exhibited excellent degradation of crude oil (>94.0%) with evidence of early degradation of isoprenoid hydrocarbons and concurrent metal removal 18 d post-inoculation. Similarly, phenanthrene degradation (>85.0%), and corresponding metal detoxification occurred in 28 d axenic culture of the strains. Strain M16K and M19F were metabolically active in matrices containing HMs, degraded hydrocarbons and simultaneously removed HMs from the medium. To the best of our knowledge, this is the first report of metal-resistant Bacillus subtilis strains showing simultaneous degradation of hydrocarbons and detoxification of metals, particularly in the Sub-Saharan Africa. The bacilli could be useful as potential biological agents in effective bioremediation campaign for multi-polluted environments.
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    Biodegradation of petroleum hydrocarbons in the presence of nickel and cobalt
    (Journal of basic microbiology, 2013-11) Oyetibo, Ganiyu O.; Ilori, Matthew O.; Obayori, Oluwafemi S.; Amund, Olukayode O.
    Bioremediation of environments co-contaminated with hydrocarbons and heavy metals often pose a challenge as heavy metals exert toxicity to existing communities of hydrocarbon degraders. Multi-resistant bacterial strains were studied for ability to degrade hydrocarbons in chemically defined media amended with 5.0 mM Ni2þ, and Co2þ. The bacteria, Pseudomonas aeruginosa CA207Ni, Burkholderia cepacia AL96Co, and Corynebacterium kutscheri FL108Hg, utilized crude oil and anthracene without lag phase at specific growth rate spanning 0.3848–0.8259 per day. The bacterial populations grew in hydrocarbon media amended with nickel (Ni) and cobalt (Co) at 0.8393–1.801 days generation time (period of exponential growth, t ¼ 15 days). The bacteria degraded 96.24–98.97, and 92.94–96.24% of crude oil, and anthracene, respectively, within 30 days without any impedance due to metal toxicity (at 5.0 mM). Rather, there was reduction of Ni and Co concentrations in the axenic culture 30 days post-inoculation to 0.08–0.12 and 0.11– 0.15 mM, respectively. The metabolic functions of the bacteria are active in the presence of toxic metals (Ni and Co) while utilizing petroleum hydrocarbons for increase in biomass. These findings are useful to other baseline studies on decommissioning of sites co-contaminated with hydrocarbons and toxic metals.
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    Biotechnological remedies for the estuarine environment polluted with heavy metals and persistent organic pollutants
    (Elsevier, 2017-04-01) Oyetibo, Ganiyu O.; Miyauchi, Keisuke; Huang, Yi; Chien, Mei-Fang; Ilori, Matthew O.; Amund, Olukayode O.; Endo, Ginro
    Estuaries in the areas prone to anthropogenic activities are exposed to multifarious pollutants. Toxic concentrations of heavy metals do exist with persistent organic compounds in such estuaries prolonging the recalcitrance and ecotoxicological consequences of the chemicals, which impact on the health of the brackish water and by extension, the oceans. The quest for high aesthetic quality of the estuarine environment is gaining attention from global campaign, which requires effective remedial strategies to replace the physical and chemical methods in use that are costly and often leave behind toxic residues in the environment. Contrary to physico-chemical remedial processes, bioremediation strategies are projected as a promising green technology to remove pollutants from the estuarine environment. The concept of bioremediation involves the use of competent biological elements such as microorganisms and plants, along with or without the biomolecules they produced, to ameliorate pollution. Therefore, this paper reviews the various bioremediation technologies that would be applicable to decommissioning estuarine environments polluted with toxic metals and persistent organic compounds.
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    Carbazole angular dioxygenation and mineralization by bacteria isolated from hydrocarbon-contaminated tropical African soil
    (Springer Berlin Heidelberg, 2014-08-01) Salam, L. B.; Ilori, Matthew O.; Amund, Olukayode O.; Numata, M.; Horisaki, T.; Nojiri, T. H.
    Four bacterial strains isolated from hydrocarbon-contaminated soils in Lagos, Nigeria, displayed extensive degradation abilities on carbazole, an N-heterocyclic aromatic hydrocarbon. Physicochemical analyses of the sampling sites (ACPP, MWO, NESU) indicate gross pollution of the soils with a high hydrocarbon content (157,067.9 mg/kg) and presence of heavy metals. Phylogenetic analysis of the four strains indicated that they were identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4, Microbacterium esteraromaticumstrain SL6, and Stenotrophomonas maltophilia strain BA. The rates of degradation of carbazole by the four isolates during 30 days of incubation were 0.057, 0.062, 0.036, and 0.050 mg L−1 h −1 for strains SL1, SL4, SL6, and BA. Gas chromatographic (GC) analyses of residual carbazole after 30 days of incubation revealed that 81.3, 85, 64.4, and 76 % of 50 mg l −1 carbazole were degraded by strains SL1, SL4, SL6, and BA, respectively. GC-mass spectrometry and high-performance liquid chromatographic analyses of the extracts from the growing and resting cells of strains SL1, SL4, and SL6 cultured on carbazole showed detection of anthranilic acid and catechol while these metabolites were not detected in strain BA under the same conditions. This study has established for the first time carbazole angular dioxygenation and mineralization by isolates from African environment.
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    Characterization of bacterial community structure in a hydrocarbon-contaminated tropical African soil
    (Taylor & Francis, 2018-04-03) Salam, Lateef B.; Ilori, Matthew O.; Amund, Olukayode O.; LiiMien, Yee; Nojiri, Hideaki
    The bacterial community structure in a hydrocarbon-contaminated Mechanical Engineering Workshop (MWO) soil was deciphered using 16S rRNA gene clone library analysis. Four hundred and thirty-seven clones cutting across 13 bacterial phyla were recovered from the soil. The representative bacterial phyla identified from MWO soil are Proteobacteria, Bacteroidetes, Chloroflexi, Acidobacteria, Firmicutes, Actinobacteria, Verrucomicrobia, Planctomycetes, Ignavibacteriae, Spirochaetes, Chlamydiae, Candidatus Saccharibacteria and Parcubacteria. Proteobacteria is preponderant in the contaminated soil (51.2%) with all classes except Epsilonproteobacteria duly represented. Rarefaction analysis indicates 42%, 52% and 77% of the clone library is covered at the species, genus and family/class delineations with Shannon diversity (H′) and Chao1 richness indices of 5.59 and 1126, respectively. A sizeable number of bacterial phylotypes in the clone library shared high similarities with strains previously described to be involved in hydrocarbon biodegradation. Novel uncultured genera were identified that have not been previously reported from tropical African soil to be associated with natural attenuation of hydrocarbon pollutants. This study establishes the involvement of a wide array of physiologically diverse bacterial groups in natural attenuation of hydrocarbon pollutants in soil.
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    Characterization of lignocellulolytic bacterial strains associated with decomposing wood residues in the Lagos lagoon, Nigeria
    (Malaysian Society of Microbiology, 2015) Buraimoh, Olanike M.; Ilori, Matthew O.; Amund, Olukayode O.
    Aims: The presence of lignocelluloses, especially sawdust in the Lagos lagoon and the attendant ecological problems warranted studies on their degradation. This study aimed to isolate and identify the indigenous bacterial strains capable of utilizing lignocellulosic wastes under the prevalent tropical estuarine conditions. Methodology and results: Nine bacterial species were obtained by elective culture from decomposing wood residues in the lagoon. They were identified on the basis of morphology, biochemical characteristics and analysis of their 16S rRNA gene sequences as Streptomyces, Bacillus and Paenibacillus species. They were cultured on various ligninrelated lignocellulosic substrates over a period of 7 to 12 days. All the isolates showed moderate to very good growth on sugarcane baggase. Streptomyces albogriseolus strain AOB and Paenibacillus sp. ROB showed good growth on grass while on sawdust, only Streptomyces AOB, and Bacillus megaterium strain NOB showed good growth. High performance liquid chromatographic analysis showed that the Streptomyces species completely utilized coniferyl alcohol, B. megaterium strain NOB utilized 90-100% of all the lignin- related aromatic compounds. All the bacterial species utilized less than 40% of sinapyl alcohol, Bacillus sp. OOB and Paenibacillus sp. strain ROB failed to utilize vanillic acid. Conclusion, significance and impact of study: The isolates degraded lignocellulosic wastes and lignin-related compounds. The role of fungi in the breakdown of lignocellulose in the Lagos lagoon had been the subject of previous research considerations whilst the role of bacteria spp was unreported. Autochthonous bacterial species may equally play a role in the bio-rehabilitation of the sawdust-polluted water of the Lagos lagoon.
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    CHARACTERIZATION OF LINAMARIN-UTILIZING BACTERIAL STRAINS ASSOCIATED WITH DETOXIFICATION OF CYANOGENS IN WASTE EFFLUENTS
    (Malaysian Applied Biology Journal, 2019-06-30) Ogunyemi, Adewale K.; Samuel, Titilola A.; Amund, Olukayode O.; Ilori, Matthew O.
    The cyanide molecule is one of the dominant pollutants in the environment. This study aimed to isolate and identify the bacterial strains capable of utilizing linamarin and to assess their roles in the detoxification of cyanogenic substances in waste effluents in Lagos, Nigeria. Two bacterial strains, Bacillus pumilus strain WOB3 KX774195 and Bacillus pumilus strain WOB7 KX774196 were isolated from cassava wastewater samples by standard microbiological procedure. They were identified on the basis of morphological and biochemical characteristics and 16S rRNA gene sequencing. Microbial growth assessment was performed in triplicates under aerobic batch conditions. The generation times of strains WOB3 and WOB7 were 40.71 and 10.88 d; with specific growth rates of 0.025 and 0.064 d-1 respectively on linamarin. Strain WOB3 had maximum growth of 0.552 (OD600nm) by day 12 at pH 6.2. Likewise, strain WOB7 recorded optimum growth of 1.276 (OD600 nm) by day 10 at pH 6.4. The maximum values obtained for linamarase activities by WOB3 and WOB7 were 3.3 x 10-2 mgmL-1min-1 and 7.61 x 10-2 mgmL-1min-1 respectively. The results from this study suggest that the bacterial isolates possess degradative capacities, which could be deployed in the bioremediation of cassava processing wastes.
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    Characterization of multiple novel aerobic polychlorinated biphenyl (PCB)-utilizing bacterial strains indigenous to contaminated tropical African soils
    (Springer Netherlands, 2008-02) Adebusoye, Sunday A.; Picardal, Flynn W.; Ilori, Matthew O.; Amund, Olukayode O.; Fuqua, Clay
    Contaminated sites in Lagos, Nigeria were screened for the presence of chlorobiphenyl-degrading bacteria. The technique of continual enrichment on Askarel fluid yielded bacterial isolates able to utilize dichlorobiphenyls (diCBs) as growth substrates and six were selected for further studies. Phenotypic typing and 16S rDNA analysis classified these organisms as species of Enterobacter, Ralstonia and Pseudomonas. All the strains readily utilized a broad spectrum of xenobiotics as sole sources of carbon and energy. Growth was observed on all monochlorobiphenyls (CBs), 2,2'-, 2,3-, 2,4'-, 3,3'- and 3,5-diCB as well as di- and trichlorobenzenes Growth was also sustainable on Askarel electrical transformer fluid and Aroclor 1221. Time-course studies using 100 ppm of 2-, 3- or 4-CB resulted in rapid exponential increases in cell numbers and CB transformation to respective chlorobenzoates (CBAs) within 70 h. Significant amounts of chloride were recovered in culture media of cells incubated with 2-CB and 3-CB, suggesting susceptibilities of both 2- and 3-chlorophenyl rings to attack, while the 4-CB was stoichiometrically transformed to 4-CBA. Extensive degradation of most of the congeners in Aroclor 1221 was observed when isolates were cultivated with the mixture as a sole carbon source. Aroclor 1221 was depleted by a minimum of 51% and maximum of 71%. Substantial amounts of chloride eliminated from the mixture ranged between 15 and 43%. These results suggest that some contaminated soils in the tropics may contain exotic micro-organisms whose abilities and potentials are previously unknown. An understanding of these novel strains therefore, may help answer questions about the microbial degradation of polychlorinated biphenyls (PCBs) in natural systems and enhance the potential use of bioremediation as an effective tool for cleanup of PCB-contaminated soils.
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    Chromium (VI) biosorption properties of multiple resistant bacteria isolated from industrial sewerage
    (Springer Netherlands, 2013-08-01) Oyetibo, Ganiyu O.; Ilori, Matthew O.; Obayori, Oluwafemi S.; Amund, Olukayode O.
    Chromium (VI) [Cr (VI)] biosorption by four resistant autochthonous bacterial strains was investigated to determine their potential for use in sustainable marine water-pollution control. Maximum exchange between Cr (VI) ions and protons on the cells surfaces were at 30–35 °C, pH 2.0 and 350–450 mg/L. The bacterial strains effectively removed 79.0–90.5 % Cr (VI) ions from solution. Furthermore, 85.3–93.0 % of Cr (VI) ions were regenerated from the biomasses, and 83.4–91.7 % of the metal was adsorbed when the biomasses was reused. Langmuir isotherm performed better than Freundlich isotherm, depicting that Cr (VI) affinity was in the sequence Rhodococcus sp. AL03Ni > Burkholderia cepacia AL96Co > Corynebacterium kutscheri FL108Hg > Pseudomonas aeruginosa CA207Ni. Biosorption isotherms confirmed that Rhodococcus sp. AL03Ni was a better biosorbent with a maximum uptake of 107.46 mg of Cr (VI) per g (dry weight) of biomass. The results highlight the high potential of the organisms for bacteria-based detoxification of Cr (VI) via biosorption.
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    Co-metabolic Degradation of Polychlorinated Biphenyls (PCBs) by Axenic Cultures of Ralstonia sp. Strain SA-5 and Pseudomonas sp. Strain SA-6 obtained from Nigerian Contaminated Soils
    (Springer Netherlands, 2008-01-01) Adebusoye, Sunday A.; Ilori, Matthew O.; Picardal, Flynn W.; Amund, Olukayode O.
    Substantial metabolism of 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-tetraCB) and 2,3′,4′,5-tetraCB by axenic cultures of Ralstonia sp. SA-5 and Pseudomonas sp. SA-6 was observed in the presence of biphenyl supplementation, although, the strains were unable to utilize tetrachlorobiphenyls as growth substrate. The former was more amenable to aerobic degradation (∼70% degradation) than the latter (22–45% degradation). Recovery of 2,5-chlorobenzoic acid and chloride from 2,3′,4′,5-tetraCB assay is an indication of initial dioxygenase attack on the 3,4-dichlorophenyl ring. The PCB-degradative ability of both strains was also investigated by GC analysis of individual congeners in Aroclor 1242 (100 ppm) following 12-day incubation with washed benzoate-grown cells. Results revealed two different catabolic properties. Whereas strain SA-6 required biphenyl as inducer of the degradation activity, such induction was not required by strain SA-5. Nearly all the detectable congeners in the mixture were extensively degraded (% reduction in ECD area counts for individual congeners ranged from 50.0 to 100% and 14.2 to 100%, respectively, for SA-5 and SA-6). The two strains exhibited no noticeable specificity for congeners with varying numbers of chlorine substitution and positions. The degradative competence of these isolates most especially SA-5 makes them among the most versatile PCB-metabolizing organisms yet reported.
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    Comparative geochemical evaluation of toxic metals pollution and bacterial communities of industrial effluent tributary and a receiving estuary in Nigeria
    (Pergamon, 2019-07-01) Oyetibo, Ganiyu O.; Miyauchi, Keisuke; Huang, Yi; Ikeda-Ohtsubo, Wakako; Chien, Mei-Fang; Ilori, Matthew O.; Amund, Olukayode O.; Endo, Ginro
    Toxic metals/metalloid contaminations of estuarine sediments due to compromised tributaries arouse significant interest in studying bacterial community that triggers natural attenuation processes. Geo-accumulation index (Igeo), contamination factor (CF), pollution load index (PLI), and Hakanson potential ecological risk index (RI) as a sum of risk factors (Er) were used to quantify toxic metal/metalloid-pollution status of Lagos Lagoon (2W) and ‘Iya-Alaro’ tributary (4W) sediments in comparison with pristine ‘Lekki Conservation Centre’ sediment (L1-B). Bacteriology of the ecosystems was based on culture-independent analyses using pyrosequencing. 2W and 4W were extremely contaminated with mercury (Igeo > 7), whereas, cadmium contamination was only observed in 4W. The two ecosystems were polluted with toxic metal based on PLI, where mercury (Er = 2900 and 1900 for 4W and 2W, respectively) posed very high ecological risks. Molecular fingerprinting revealed that Proteobacteria, Firmicutes, and Acidobacteria predominately contributed the 20 most abundant genera in the two ecosystems. The 240 and 310 species present in 2W and 4W, respectively, but absent in L1-B, thrive under the metal concentrations in the polluted hydrosphere. Whereas, the 58,000 species missing in 2W and 4W but found in L1-B would serve as indicators for systems impacted with metal eco-toxicity. Despite toxic metal pollution of the ecosystems understudied, bacterial communities play vital roles in self-recovery processes occurring in the hydrosphere.
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    A Comparative Study of Biosurfactant Synthesis by Pseudomonas aeruginosa Isolated from Clinical and Environmental Samples
    (Taylor & Francis Group, 2012-02-15) Agwu, O. A.; Ilori, Matthew O.; Adebusoye, S. A.; Amund, Olukayode O.
    Evaluation of emulsifying activities indicates that biosurfactants were produced by an environmental (strain EP1) and a clinical (strain CP1) species of Pseudomonas aeruginosa. During growth on hydrocarbons, the organisms produced biosurfactants. Both strains grew luxuriantly on motor oil and readily synthesized abundant surfactants at the expense of easily metabolizable substrates. During a 12-day cultivation on motor oil, the organisms produced growth-associated extracellular surfactants with emulsification activities of 71 and 38% for EP1 and CP1, respectively. The generation times obtained for EP1 and CP1 were 1.74 and 2.66 days. The biosurfactants that could not be secreted on glucose were partially purified and putatively identified as rhamnolipids. The surface-active compounds present high emulsification activity and stability in the pH range of 3.0–10.0, temperature range of 4°C–100°C, and salinity range of 16–44% and are capable of stabilizing oil-in-water emulsions with several hydrocarbons. Typical emulsions produced were stable for several weeks. The results also showed that the biosurfactants were able to remove a significant amount of crude oil from contaminated soil; for instance, strain EP1 surfactant removed 54%, CP1 41%, detergent 42%, and water 30%. The rhamnolipids from these strains represent a new class of biosurfactants that have potential for use in a variety of biotechnological and industrial applications where extremes of pH, thermal, and saline conditions would have little or no effect on activity.
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    Degradation of commercial detergent products by microbial populations of the Lagos lagoon
    (Springer Netherlands, 1997-08-01) Amund, Olukayode O.; Ilori, Matthew O.; Odetundun, F. R.
    The biodegradability potentials of three detergent products with the trade names Omo, Teepol and sodium dodecyl sulfate (SDS) by the native bacteria of the Lagos lagoon was carried out using the lagoon die-away method. Physicochemical parameters of the water samples showed that the lagoon in Apapa was more polluted than at the University of Lagos. In 12 days, approximately 30, 60 and 97%Omo, Teepol and SDS respectively were degraded. SDS with an alkyl sulfate moiety as surface supported the higest growth of the detergent-utilizing organisms, indicating that the components of Omo and Teepol are more resistant to microbial attack. The detergent-utilizing bacteria identified were mainly Gram-negative and of the following genera: Vibrio, Klebsiella, Flavobacterium, Pseudomonas, Escherichia, Enterobacter, Proteus, Shigella and Citrobacter. Vibrio was the most frequently encountered organism while Proteus was the rarest. Results of this investigation had shown that detergents made in Nigeria may still contain components that are recalcitrant to biodegradation.
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    The degradation of coniferyl alcohol and the complementary production of chlorogenic acids in the growth culture of Streptomyces albogriseolus KF977548 isolated from decaying wood residues
    (Elsevier, 2017-01-01) Buraimoh, Olanike M.; Ilori, Matthew O.; Amund, Olukayode O.; Isanbor, Chukwuemeka; Michel Jr, Frederick C.
    Coniferyl alcohol is one of the major precursors of lignin; the most abundant aromatic compound and a natural resource currently receiving attention because of the value-added metabolites resulting from its degradation. Growth study of Streptomyces albogriseolus KF977548 (strain AOB) isolated from decaying wood residues in a tropical estuarine ecosystem was carried out using coniferyl alcohol as a sole carbon source. Cell growth and metabolite production were monitored at 24 h interval by dry weight measurements and HPLC, LC–MS-DAD analyses. Biochemical and PCR assays were carried out to detect the major catabolic enzymes of interest. Strain AOB utilized coniferyl alcohol completely within 72 h ( = 0.204 h−1, Td = 3.4 h). Laccase and peroxidase were released into the growth medium up to 0.099 and 98 mol/mL respectively. Protocatechuate 3, 4-dioxygenase and demethylase were detected in the genome whilst ortho-adipate pathway was clearly indicated. Growth on coniferyl alcohol or caffeic acid as mono substrates resulted in the production of secondary metabolites identified by HPLC–MS as 1- caffeoylquinic and 3,4,5-tricaffeoylquinic acids, known as chlorogenic acids, in the culture medium. The microbial production of chlorogenic acids from a lignin-related substrate base by strain AOB could arouse a plausible biotechnological process.
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    Degradation of hydrocarbons and biosurfactant production by Pseudomonas sp. strain LP1
    (Springer Netherlands, 2009-09-01) Obayori, Oluwafemi S.; Ilori, Matthew O.; Adebusoye, Sunday A.; Oyetibo, Ganiyu O.; Omotayo, Ayodele E.; Amund, Olukayode O.
    Pseudomonas sp. strain LP1, an organism isolated on the basis of its ability to grow on pyrene, was assayed for its degradative and biosurfactant production potentials when growing on crude, diesel and engine oils. The isolate exhibited specific growth rate and doubling time of 0.304 days⁻¹ and 2.28 days, respectively on crude oil (Escravos Light). The corresponding values on diesel were 0.233 days⁻¹ and 2.97 days, while on engine oil, were 0.122 days⁻¹ and 5.71 days. The organism did not show significant biosurfactant production towards crude oil and diesel, but readily produced biosurfactant on engine oil. The highest Emulsification index (E₂₄) value for the biosurfactant produced by LP1 on engine oil was 80.33 ± 1.20, on day 8 of incubation. Biosurfactant production was growth-associated. The surface-active compound which exhibited zero saline tolerance had its optimal activity at 50°C and pH 2.0.
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    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.