Browsing by Author "Salam, Lateef B."
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Item Acenaphthene biodegradation and structural and functional metagenomics of the microbial community of an acenaphthene-enriched animal charcoal polluted soil(Biocatalysis and Agricultural Biotechnology, 2021-02) Salam, Lateef B.; Obayori, Oluwafemi S.; Ilori, Mathew O.; Amund, Olukayode O.Animal charcoal from skin and hides cottage industries indiscriminately disposed in run offs and drainage channels harbors hazardous constituents that are mutagenic and toxic, and thus require bio-based ecofriendly depuration strategies. A microbial consortium (FN7) from an animal charcoal polluted site enriched with acenaphthene was structurally and functionally characterized via illumina next generation sequencing and annotation of their putative ORFs, and also studied for ability to degrade acenaphthene. Structurally, FN7 metagenome consists of 7 phyla, 13 classes, 38 orders, 49 families, 67 genera, 68 species, and 45 strains, respectively. The dominant phylum, class, order, family, genus, species, and strain in the metagenome are Proteobacteria (48.9%), Actinobacteria (31.8%), Actinomycetales (28.0%), Enterobacteriaceae (18.9%), Paracoccus (12.9%), Bacillus cereus group (13.5%), and Methylobacterium radiotolerans JCM 2831 (22.4%). The microbial consortium in the metagenome degraded 59.68% (29.84 mg l−1) and 89.16% (44.58 mg l−1) of the initial concentration of acenaphthene (50 mg l−1) in 14 and 21 days. Functional annotation of the putative ORFs of the metagenome using KEGG KofamKOALA, NCBI's conserved domain database, BacMet, and Antibiotic Resistance Gene-ANNOTation (ARG-ANNOT) revealed the detection of hydrocarbon-degradation genes including salicylaldehyde dehydrogenase and catechol 1,2 dioxygenase involved in acenaphthene degradation, resistance genes for mercury, arsenic, cadmium, nickel, and several others, and antibiotic resistance genes for 15 antibiotic classes such as β-lactam, colistin, aminoglycoside, among others. This study revealed that members of FN7 metagenome are equipped with requisite gene batteries and could be veritable bioresources for in vitro biodegradation as well as on-site bioremediation of animal charcoal polluted sites.Item Biodegradation of anthracene by a novel actinomycete, Microbacterium sp. isolated from tropical hydrocarboncontaminated soil(Springer: World Journal of Microbiology and Biotechnology, 2013-07) Salam, Lateef B.; Obayori, Oluwafemi S.; Olatoye, Nojeem O.A novel anthracene-degrading Gram-positive actinomycete, Microbacterium sp. strain SL10 was isolated from a hydrocarbon-contaminated soil at a mechanical engineering workshop in Lagos, Nigeria. The polluted soil had an unusually high total hydrocarbon content of 157 g/kg and presence of various heavy metals. The isolate tolerated salt concentration of more than 4 %. It resisted cefotaxime, streptomycin and ciprofloxacin, but susceptible to meropenem, linezolid and vancomycin. The isolate exhibited growth rate and doubling time of 0.82 days-1 and 0.84 days, respectively on anthracene. It degraded 57.5 and 90.12 % of anthracene within 12 and 21 days, respectively while the rate of anthracene utilization by the isolate was 4.79 mg l-1 d-1. To the best of our knowledge, this is the first report of isolation and characterization of anthracene-degrading Microbacterium sp.Item Biodegradation of Bonny Light crude oil by bacteria isolated from contaminated soil(INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY, 2011) Salam, Lateef B.; OBAYORI, OLUWAFEMI SUNDAY; AKASHORO, OMOKOREDE SULIKURNAINI; OKOGIE, GENEVIEVE OLUBUNMITwo hydrocarbon degraders isolated from an abandoned coal power plant soil in Lagos, Nigeria, were tested. The isolates were identified as belonging to the genus Pseudomonas. P. putida G1 exhibited strong degradative ability on crude oil, kerosene, fair ability on engine oil, brake oil and petrol and a weak ability on pyrene, while P. aeruginosa K1 had corresponding values of 0.21days-1 and 3.31 days. The amount of crude oil degraded by strain G1 and K1 after a 21 day incubation period were 92.05% and 90.89% respectively. Data obtained from gas chromatographic analysis of oil recovered from culture fluids of G1 and K1 confirmed a near-disappearance of aliphatic fractions and a significant reduction of aromatic fractions in the hydrocarbon mixture. © 2010 Friends Science PublishersTwo hydrocarbon degraders isolated from an abandoned coal power plant soil in Lagos, Nigeria, were tested. The isolates were identified as belonging to the genus Pseudomonas. P. putida G1 exhibited strong degradative ability on crude oil, kerosene, fair ability on engine oil, brake oil and petrol and a weak ability on pyrene, while P. aeruginosa K1 had corresponding values of 0.21days-1 and 3.31 days. The amount of crude oil degraded by strain G1 and K1 after a 21 day incubation period were 92.05% and 90.89% respectively. Data obtained from gas chromatographic analysis of oil recovered from culture fluids of G1 and K1 confirmed a near-disappearance of aliphatic fractions and a significant reduction of aromatic fractions in the hydrocarbon mixture.Item Biodegradation of Fresh and Used Engine Oils by Pseudomonas aeruginosa LP5(Bioremediation & Biodegradation, 2014-01-23) Obayori, Oluwafemi S; Salam, Lateef B.; Ogunwumi, Oluwatoba S.Pseudomonas aeruginosa strain LP5, a hydrocarbon degrader isolated from petroleum contaminated soil based on its ability to grow on pyrene, was used to degrade two different grades of fresh and used engine oil (SAE 40W and SAE 20W 50) in liquid cultures. The organism degraded more than 90 percent of all oil types within 21 days with values of 95%, 93%, 96% and 92% for fresh SAE 40W, used SAE 40W, fresh SAE 20W 50 and used SAE 20W 50 respectively. Similarly, growth rates were slightly higher in the fresh oils with values of 0.17, 0.13, 0.14 and 0.13 d-1 recorded respectively for fresh SAE 40W, used SAE 40W, fresh SAE 20W 50 and used SAE 20W 50. Significantly higher initial rates of degradation of 177.42 mg l-1d-1 and 207.14 mgl-1d-1 were recorded for fresh SAE 40 and SAE 20W 50 in the first 21 days compared to the values for the used oil counterparts, which were 73.23 mgl-1d-1 for SAE 40 and 74.37 mgl-1d-1 for SAE 20W 50. In the used oils, lower peaks that were not present at Day 0 reappeared on Day-21. All peaks greater than C20 also disappeared. In all cases, it was the medium fraction ranges of C14, C15, and C17 that remained with discernible peaks on Day 21, albeit at very low heights of less than 10% of Day 0 values. Thus whereas degradation rates differ on oil types and fresh oil appear more amenable to early degradation, the organism Pseudomonas aeruginosa LP5 showed remarkable potential for use in degradation of both fresh and used engine oils.Item Biodegradation of Used Engine Oil by a Methylotrophic Bacterium, Methylobacterium Mesophilicum Isolated from Tropical Hydrocarbon-contaminated Soil(Taylor and Francis: Petroleum Science and Technology Journal, 2014-12) Salam, Lateef B.; Obayori, Oluwafemi Sunday; Raji, S. A.A Gram-negative facultatively methylotrophic bacterium putatively identified as Methylobacterium mesophilicum strain RD1 displayed extensive degradative ability on used engine oil (SAE 40W) in liquid cultures. The rate of degradation of used engine oil (1274.85 mg L−1) by the isolate, for the first 12 days and the last 9 days were 65 and 40 mg L−1 d−1, respectively. Gas chromatographic (GC) analyses of residual used engine oil revealed that 61.2% and 89.5% of the initial concentration of the used engine oil were degraded within 12 and 21 days. GC fingerprints of the used engine oil after 12 days of incubation showed total disappearance of C15, C23, C24, C25, and C26 hydrocarbon fractions as well as drastic reductions of C13, C14, C16, and PAHs fractions such as C19-Anthracene and C22-Pyrene. At the end of 21 days’ incubation, total disappearance of C17-pristane, C22-pyrene, one of the C19-anthracene, and significant reduction of C18-phytane (96.8%) fractions were observed. In addition, less than 10% of Day 0 values of medium fraction ranges C13, C14, and C16 were discernible after 21 days. This study has established the potential of Methylobacterium mesophilicum strain RD1 in degradation of aliphatic, aromatic, and branched alkane components of used engine oils.Item Biodegradation of Used Engine Oil by a Methylotrophic Bacterium, Methylobacterium Mesophilicum Isolated from Tropical Hydrocarbon-contaminated Soil(Petroleum Science and Technology, 2014-12) Salam, Lateef B.; Obayori, Oluwafemi Sunday; Raji, S. A.A Gram-negative facultatively methylotrophic bacterium putatively identified as Methylobacterium mesophilicum strain RD1 displayed extensive degradative ability on used engine oil (SAE 40W) in liquid cultures. The rate of degradation of used engine oil (1274.85 mg L−1) by the isolate, for the first 12 days and the last 9 days were 65 and 40 mg L−1 d−1, respectively. Gas chromatographic (GC) analyses of residual used engine oil revealed that 61.2% and 89.5% of the initial concentration of the used engine oil were degraded within 12 and 21 days. GC fingerprints of the used engine oil after 12 days of incubation showed total disappearance of C15, C23, C24, C25, and C26 hydrocarbon fractions as well as drastic reductions of C13, C14, C16, and PAHs fractions such as C19-Anthracene and C22-Pyrene. At the end of 21 days’ incubation, total disappearance of C17-pristane, C22-pyrene, one of the C19-anthracene, and significant reduction of C18-phytane (96.8%) fractions were observed. In addition, less than 10% of Day 0 values of medium fraction ranges C13, C14, and C16 were discernible after 21 days. This study has established the potential of Methylobacterium mesophilicum strain RD1 in degradation of aliphatic, aromatic, and branched alkane components of used engine oils.Item Biodegradation potentials of polyaromatic hydrocarbon (pyrene and phenanthrene) by Proteus mirabilis isolated from an animal charcoal polluted site(Elsevier, 2017-10-01) Obayori, Oluwafemi S.; Salam, Lateef B.; Oyetibo, Ganiyu O.; Idowu, Monsurat; Amund, Olukayode O.Indiscriminate disposal of animal charcoal from skin and hides cottage industries often impact the environments with toxic hydrocarbon components and thus require eco-friendly remedial strategies. A bacterial strain isolated from a site polluted with animal charcoal was characterized, identified as Proteus mirabilis 10c, and studied for ability to degrade pyrene and phenanthrene. The bacterium resisted 30 µg chloramphenicol, 10 µg ampicillin, 30 µg amoxicillin and 10 µg perfloxacin; while it utilized a number of polycyclic aromatic hydrocarbons and cinnamic acid. Specific growth rate on pyrene and phenanthrene were 0.281 d−1 and 0.276 d−1, respectively. Kinetics of degradation of pyrene was 87.92 mg l−1 in 30 days at the rate of 2.93 mg l−1 d−1, biodegradation constant at 0.073 d−1 and half-life of 9.50 d. The corresponding values for phenanthrene degradation kinetics by the bacterium were 90.12 mg l−1, 3.02 mg l−1 d−1, 0.079 d−1 and 8.77 d, respectively. Efficient degradation of crude oil (92.3%) in chemically defined medium was evident with near-disappearance of most aromatic spectra in 30 days. Considering its unique physiologies and broad specificities for aromatic and aliphatic hydrocarbons, the bacterium has potentials for decommissioning environments contaminated with toxic components of animal charcoal.Item Biostimulation potentials of corn steep liquor in enhanced hydrocarbon degradation in chronically polluted soil(Springer : Biotech, 2019-01-23) Salam, Lateef B.; Ishaq, AishaThe effects of corn steep liquor (CSL) on hydrocarbon degradation and microbial community structure and function was evaluated in field-moist soil microcosms. Chronically polluted soil treated with CSL (AB4) and an untreated control (3S) was compared over a period of 6 weeks. Gas chromatographic fingerprints of residual hydrocarbons revealed removal of 95.95% and 94.60% aliphatic and aromatic hydrocarbon fractions in AB4 system with complete disappearance of nC1– nC8, nC10, nC15, nC20– nC23 aliphatics and aromatics such as naphthalene, acenaphthylene, fluorene, phenanthrene, pyrene, benzo(a)anthracene, and indeno(123-cd)pyrene in 42 days. In 3S system, there is removal of 61.27% and 66.58% aliphatic and aromatic fractions with complete disappearance of nC2 and nC21 aliphatics and naphthalene, acenaphthylene, fluorene, phenanthrene, pyrene, and benzo(a)anthracene aromatics in 42 days. Illumina shotgun sequencing of the DNA extracted from the two systems showed the preponderance of Actinobacteria (31.46%) and Proteobacteria (38.95%) phyla in 3S and AB4 with the dominance of Verticillium (22.88%) and Microbacterium (8.16%) in 3S, and Laceyella (24.23%), Methylosinus (8.93%) and Pedobacter (7.73%) in AB4. Functional characterization of the metagenomic reads revealed diverse metabolic potentials and adaptive traits of the microbial communities in the two systems to various environmental stressors. It also revealed the exclusive detection of catabolic enzymes in AB4 system belonging to the aldehyde dehydrogenase superfamily. The results obtained in this study showed that CSL is a potential resource for bioremediation of hydrocarbon-polluted soils.Item Carbazole Degradation in the Soil Microcosm by Tropical Bacterial Strains(Sociedade Brasileira de Microbiologia, 2015-12) Salam, Lateef B.; Ilori, Olukayode O.; Amund, Olukayode O.In a previous study, three bacterial strains isolated from tropical hydrocarbon-contaminated soils and phylogenetically identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4 and Microbacterium esteraromaticum strain SL6 displayed angular dioxygenation and mineralization of carbazole in batch cultures. In this study, the ability of these isolates to survive and enhance carbazole degradation in soil were tested in field-moist microcosms. Strain SL4 had the highest survival rate (1.8 x 107 cfu/g) after 30 days of incubation in sterilized soil, while there was a decrease in population density in native (unsterilized) soil when compared with the initial population. Gas chromatographic analysis after 30 days of incubation showed that in sterilized soil amended with carbazolev(100 mg/kg), 66.96, 82.15 and 68.54% were degraded by strains SL1, SL4 and SL6, respectively, with rates of degradation of 0.093, 0.114 and 0.095 mg kg-1 h-1. The combination of the three isolates as inoculum in sterilized soil degraded 87.13% carbazole at a rate of 0.121 mg kg-1 h-1. In native soil amended with carbazole (100 mg/kg), 91.64, 87.29 and 89.13% were degraded by strains SL1, SL4 and SL6 after 30 days of incubation, with rates of degradation of 0.127, 0.121 and 0.124 mg kg-1 h-1, respectively. This study successfully established the survivability (> 106 cfu/g detected after 30 days) and carbazole-degrading ability of these bacterial strains in soil, and highlights the potential of these isolates as seed for the bioremediation of carbazole-impacted environments.Item 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, HideakiThe 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.Item Consequences of crude oil contamination on the structure and function of autochthonous microbial community of a tropical agricultural soil(Springer : Environmental Sustainability, 2019-05-22) Salam, Lateef B.; Idris, HadizaCrude oil contamination of soil matrices is a persistent problem with deleterious consequences due to the recalcitrant, toxic and mutagenic properties of its constituents. To decipher the effects of crude oil contamination on the microbial community structure and function of an agricultural soil, field moist soil microcosms 2S (agricultural soil) and AB6 (agricultural soil polluted with crude oil) were set up. Taxonomic profiling of the two microcosms using next generation shotgun sequencing revealed massive decline in the number of recovered sequences from 3,267,616 (2S) to 250,241 (AB6). It also revealed the dominance of the phyla Actinobacteria (46.86%), and Firmicutes (51.20%) in 2S and AB6 with preponderance of Conexibacter (11.40%), and Singulisphaera (4.43%) in 2S, and Bacillus (38.52%), Sphingobium (10.51%), and Clostridium (7.06%) in AB6, respectively. Gas chromatographic fingerprints of residual crude oil in AB6 revealed complete disappearance of 50% of the hydrocarbon fractions at the end of 42 days while the others were degraded to < 6% of their initial concentrations. Functional annotation of the predicted ORFs in the two metagenomes revealed diverse metabolic features of the autochthonous microbial community. It also revealed the exclusive detection of diverse genes in AB6 metagenome responsible for degradation of various classes of hydrocarbons and the detoxification, transport and resistance to heavy metals. This study has established the deleterious effects of crude oil contamination on the microbial community structure of a tropical agricultural soil and revealed the adaptive features of the microbial community to various environmental stressors.Item Degradation of crude oil (Escravos light) by Pseudomonas strains isolated from poultry droppings and cow dung.(LASU Journal of Research and Review in Science, 2017-12) Obayori, Oluwafemi Sunday; Salam, Lateef B.; Ogunmakinwa, Olubusola Olayinka; Ogunleye, Moyosore AdedolamuIntroduction: Poultry manure and cow dung have been established as potential material for the bioremediation of petroleum polluted sites, with emphasis on nutrient addition. Aim: Our aim was to isolate from poultry droppings and cow dung bacteria with ability to degrade petroleum hydrocarbons. Materials and Methods: Bacteria were isolated from poultry droppings and cow dung by continuous enrichment and vapor transfer techniques. Petroleum utilization by each isolate was confirmed in carbon free medium containing Escravos crude oil (1%). The two best isolates were selected for further study. Isolates were identified by Analytical Profile Index (API). Antibiotic sensitivity was determined by multidisc (Abitek Multidisc, UK). Growth was assayed in broth culture by plate count. Residual oil was determined by Gas Chromatography equipped with Flame Ionisation detector (GC-FID). Results: The isolates were putatively identified as Pseudomonas putida (MP2) and Pseudomonas sp. (MC4). Both isolates were susceptible to ciprofloxacin and chloramphenicol and tarivid. They resisted amoxicillin and gentamycin, augmentin, sparfloxacin and septrin. The growth rates were 0.17 and 0.23/day for strains MP2 and MC4 respectively, while the organisms degraded 88.39% and 89.06 % of crude oil respectively in 20 days. Aliphathic hydrocarbons in the range C11 to C22 were mostly reduced to less than 20%, while C22 – C26 disappeared completely within the same period in both cases. Conclusion: Bacteria capable of extensive degradation of Escravos crude oil were isolated from poultry droppings and cow dung. Such isolates could be veritable candidates for bioaugmentation of hydrocarbon polluted environmental compartments.Item Degradation of polycyclic aromatic hydrocarbons: Role of plasmids(Academic Journals : Scientific Research and Essays, 2010-12-24) Obayori, Oluwafemi S.; Salam, Lateef B.Polycyclic aromatic compounds are a group of highly recalcitrant organic pollutants. The initial steps in the degradation of polycyclic aromatic hydrocarbon (PAHs) involve the dihydroxylation of the aromatic ring, a step catalysed by dioxygenase enzymes. The degradation of many xenobiotic and hydrocarbon compounds is known to be mediated by plasmid encoded enzymes. In this review, an insight is given into the role of plasmid in degradation of PAHs, acquisition of degradative ability by these organisms via horizontal transfer and clustering, resulting from tranposon-mediated recombination. There is preponderance of information showing high level of plasmid involvement in the degradation of naphthalene and other 2- and 3-ring PAHs. Information on higher molecular weight PAHs is however scanty. Recent studies suggest possible involvement of plasmid in HMWPAH degradation than was previously thought. Many plasmids involved in PAH-degradation are megaplasmids, of linear configuration, encoding part or the whole genes for the complete pathways. In recent times, validation of propositions on degradative gene acquisition by horizontal gene transfer (HGT) has been obtained from field studies. HGT and transposition seems to be more chronologically linked and less fortuitously directed than previously thought. Improvement on the methods used in isolation of degraders and study of these is important, towards making a significant stride in elucidating plasmid involvement in PAH degradationItem 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 weathered crude oil (Escravos Light) by bacterial strains from hydrocarbons-polluted site(African Journal of Microbiology Research, 2011-06-30) Obayori, Oluwafemi S.; Salam, Lateef B.; Omotoyo, Ibiyemi M.Two hydrocarbon degrading Gram-negative bacteria isolated from hydrocarbon polluted power plant soil in Lagos, Nigeria, were studied for their degradation potentials on weathered crude oil (Escravos Blend). These bacteria isolates were identified as Enterobacter cloacae strain LG1 and Burkholderia cepacia strain LG2. The highest population density for LG1 was 2.07 x 107 cfu/ml, while for LG2 it was 1.63 x 107 cfu/ml. In the two cases slight but consistent pH drops to < 6.51 were observed. LG1 had a growth rate of 0.38 d-1 and doubling time 1.83 d. The corresponding values for LG2 during the first log phase were 0.58 d-1 and 1.19 d, respectively, while in the second log phase the values were 0.14 d-1 and 5.13 d Gas chromatographic analysis showed that chrysene was degraded by LG and LG2 by 92.91 and 80.25%, respectively, anthracene by 92.21 and 91.53%, respectively, and Benzo (b) fluoranthene was degraded by 77.19 and 98.41%, respectively. LG2 had a higher degradative capability of the polyaromatic fractions with 80.15% while LG I was lower at 52.33%. Statistical analysis showed that there was a significant difference (p < 0.05) in the degradation of various aromatic components of the oil by LG1 and LG2.Item Detection of biosynthetic genes of microbially-synthesized secondary metabolites in a contaminated tropical agricultural soil(Springer: Biologia, 2021-08-16) Salam, Lateef B.; Obayori, Oluwafemi S.; Mohammed, Mutiat O.The hunt for microbially-synthesized secondary metabolites have long generate exceptional interest due to their unique functionalities. In this study, shotgun metagenomic was used to decipher the array of secondary metabolites present in a contaminated agricultural soil (AB1) via detection of their biosynthetic genes. Functional annotation of AB1 metagenome’s putative open reading frames (ORFs) for polyketide synthases (PKSs) and non-ribosomal peptide synthetases (NRPSs) revealed that majority of the detected biosynthetic genes belong to type I polyketides and non-ribosomal peptides. Biosynthetic genes for type I polyketides such as macrolides, polyene macrolides, rapamycin-related compounds (FK506, FKF20), myxobacterial compounds (epothilone A, soraphen A), lovastatin, enediynes, among others were detected. Similarly, biosynthetic genes for non-ribosomal peptides such as surfactin, fengycin, iturin, lichenysin, arthrofactin, vibriobactin, mycobactin, bacitracin, gramicidin S, viomycin, bleomycin, vancomycin, pristinamycin, tyrocidine, fumiquinazoline and several others were also detected. Taxonomic characterization of the detected biosynthetic genes revealed microorganisms that are not known to be natural producers of the secondary metabolites, thus pointing to the possibility of horizontal gene transfer. The huge repository of these genes in the soil environment is a clear reminder of the pivotal role the soil as a natural resource can play as a source of exciting natural products that can be deployed as viable alternatives to solve myriad of challenges facing the medical, industrial, and environmental settings.Item Detection of carbohydrate-active enzymes and genes in a spent engine oil-perturbed agricultural soil(Bulletin of the National Research Centre, 2018-08) Salam, Lateef B.Background: The purpose of this study is to decipher the diverse carbohydrate metabolism pathways in a spent engine oil-perturbed agricultural soil, enunciate the carbohydrate-active enzymes and genes involved in the process, taxonomically classify the annotated enzymes and genes, and highlight the importance of the study for ecological and biotechnological processes. Results: Functional analysis of the metagenome of spent engine oil (SEO)-contaminated agricultural soil (AB1) using the Kyoto Encyclopedia of Genes and Genomes (KEGG) GhostKOALA, Cluster of Orthologous Groups (COG) of proteins, the Carbohydrate-Active Enzymes (CAZy) database, and the NCBI’s conserved domain database (CDD) revealed extensive metabolism of carbohydrates via diverse carbohydrate-active enzymes and genes. Enzymes and genes annotated for glycolysis/gluconeogenesis pathway, citric acid (TCA) cycle, pentose phosphate pathway, and pyruvate metabolism, among others, were detected, and these were not detected in the original agricultural soil (1S). Analysis of carbohydrate-active enzymes, using the CAZy database, showed 45 CAZy families with preponderance of glycoside hydrolases (GHs, 46.7%), glycosyltransferases (GTs, 24.4%), and carbohydrate-binding modules (CBMs, 15.5%). Taxonomic classification of the annotated enzymes and genes for carbohydrate metabolism using the GhostKOALA and CAZy databases revealed the predominance of the phylum Proteobacteria with the representative genera Pseudomonas (18%), Sphingobium (13.5%), and Sphingomonas (4.5%), respectively. Biotechnologically important enzymes such as xylanases, endoglucanases, α- and β-glucosidases and glycogen debranching enzymes were also retrieved from the metagenome. Conclusions: This study revealed the presence of diverse carbohydrate-active enzymes and genes mediating various carbohydrate metabolism pathways in the SEO-perturbed soil metagenome. It also reveals the detection of biotechnologically important enzymes with potentials for industrial use.Item Enhanced Degradation of Petroleum Hydrocarbons in Corn-Steep-Liquor-Treated Soil Microcosm(Taylor and Francis: Soil and Sediment Contamination: An International Journal, 2015-06) Obayori, Oluwafemi S.; Salam, Lateef B.; Anifowoshe, Wusamot T.; Odunewu, Zainab M.; Amosu, Odunayo E.; Ofulue, Bukola E.The efficiency of corn steep liquor (CSL) as a potential stimulant for remediation of hydrocarbon-contaminated soil was evaluated in soil microcosms. Chronically polluted soil samples treated with CSL, water, and un untreated control were compared over a period of 42 days. There were remarkable changes in the physicochemical status of the soil in the CSL-treated set-up with noticeable utilization of essential nutrients such as nitrogen, phosphorus, and potassium. Percentage hydrocarbon utilizers showed a concomitant increase with hydrocarbon utilization in CSL-treated (0.05–0.16%) and water-treated (0.02–0.12%) set-ups, while no significant changes occurred in the untreated control. Gas chromatographic fingerprints showed complete disappearance of the lower-fraction alkanes C7, C8, C9, and C11 within 21 days, as well as some higher fractions, significantly C16 and C29, in the CSL-treated set-up. In the CSL-treated set-up, 77.9% of hydrocarbon was degraded, while the corresponding values for the water-treated and untreated control were 40.55 and 30.6%, respectively. The percentage aliphatic components degraded differed significantly in the CSL-treated, water-treated, and untreated set-ups. The n- C17/pristane and n-C18/phytane ratios in the CSL-treated set-up were 1.298 and 1.153, respectively, on day 0, but at the end of the treatability period, the values had dropped drastically to 0.182 and 0.585, respectively. The results of this study show that corn steep liquor is a potential material for bioremediation of hydrocarbonpolluted sites.Item Fluorene biodegradation potentials of Bacillus strains isolated from tropical hydrocarbon-contaminated soils(Academic Journals : African Journal of Biotechnology, 2014-03-24) Salam, Lateef B.; Obayori, Oluwafemi SundayTwo fluorene-degrading Gram-positive Bacillus strains, putatively identified as Bacillus subtilis BM1 and Bacillus amyloliquefaciens BR1 were isolated from hydrocarbon-and asphalt-contaminated soils in Lagos, Nigeria. The polluted soils have a relatively high total hydrocarbon content (16888.9 and 9923.1 mg/kg, respectively), very low concentrations of macronutrients and the total organic carbon was less than 4%. The two strains tolerated NaCl concentration of up to 7% while strain BR1 exhibited moderate growth at 10%. Shared resistance to ceftriazone and cotrimozaxole were exhibited by both strains while only strain BM1 was resistant to both amoxycilin and streptomycin. The rate of degradation of fluorene (50 mg/L) by the two isolates, after 30 days of incubation were 0.09 and 0.08 mg/L/h for strains BM1 and BR1, respectively. Gas chromatographic analyses of residual fluorene, revealed that 56.9 and 46.8% of 50 mg/L fluorene was degraded in 12 days by strains BM1 and BR1. However, after 21 days on incubation, 86 and 82% of 50 mg/L fluorene were degraded by strains BM1 and BR1, respectively. To the best of our knowledge, this is the first report highlighting flourene degradation potential of Bacillus strains isolated from tropical African environmentItem Hydrocarbon Degradation and Biosurfactant Production by an Acenaphthene-degrading Pseudomonas Species(Taylor and Francis: Soil and Sediment Contamination: An International Journal, 2016-08) Salam, Lateef B.; Obayori, Oluwafemi S.; Hawa, ObajeAn acenaphthene-degrading bacterium putatively identified as Pseudomonas sp. strain KR3 and isolated from diesel-contaminated soil in Lagos, Nigeria was investigated for its degradative and biosurfactant production potentials on crude oil. Physicochemical analysis of the sampling site indicates gross pollution of the soil with high hydrocarbon content (2100 mg/kg) and detection of various heavy metals. The isolate grew luxuriantly on crude oil, engine oil and acenaphthene. It was resistant to septrin, amoxicillin and augmentin but was susceptible to pefloxacin, streptomycin and gentamycin. It was also resistant to elevated concentration of heavy metals such as 1–15 mM lead, nickel and molybdenum. On acenaphthene, the isolate exhibited specific growth rate and doubling time of 0.098 day¡1 and 3.06 days, respectively. It degraded 62.44% (31.2 mg/l) and 91.78% (45.89 mg/l) of 50 mg/l acenaphthene within 12 and 21 days. On crude oil, the specific growth rate and doubling time were 0.375 day¡1 and 1.85 days with corresponding percentage degradation of 33.01% (903.99 mg/l) and 87.79% (2403.71 mg/l) of crude oil (2738.16 mg/l) within 9 and 18 days. Gas chromatographic analysis of residual crude oil at the end of 18 days incubation showed significant reductions in the aliphatic, alicyclic and aromatic fractions with complete disappearance of benzene, propylbenzene, pristane, phytane, and nC18-octadecane fractions of the crude oil. The isolate produced growth-associated biosurfactant on crude oil with the highest emulsification index (E24) value of 72% § 0.23 on Day 10 of incubation. The partially purified biosurfactant showed zero tolerance for salinity and had its optimal activity at 27 C and pH 2.0.