Browsing by Author "Samuel, Titilola A."
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Item 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, AloCassava, 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.Item Cassava Wastewater and Solid Waste Leachate as Cyanogenic Substrates for the Growth of Nitrile and Linamarin-Utilizing Bacteria(Journal of Tropical Life Science, 2019) Ogunyemi, Adewale K.; Samuel, Titilola A.; Ilori, Mathew O.; Amund, Olukayode O.The direct discharge of wastewaters containing cyanogenic compounds poses severe health hazards, hence this study aimed to establish the biodegradative potential of nitrile and linamarin utilizing bacterial strains in the degradation of cyanogens in cassava wastewaters (CWW) and solid waste leachates (SWL). Glutaronitrile-utilizing bacterial strains (Bacillus sp. strain WOD8 KX774193 and Corynebacterium sp. strains WOIS2 KX774194) were isolated from solid waste leachates while linamarin-utilizing bacteria strains (Bacillus pumilus strain WOB3 KX774195 and Bacillus pumilus strain WOB7 KX774196) were isolated from cassava wastewaters. They were identified on the basis of morphological and biochemical characteristics, microscopic and 16S rRNA gene sequencing. Microbial growth assessment coupled with pH changes were performed under aerobic batch conditions. Growth was evaluated at intervals (2 days) by the intensity of turbidity (O.D. 600 nm) in CWW and SWL media. The doubling times of strains WOD8 and WOIS2 when grown on CWW and SWL (without supplementing mineral salts medium) were 12.83 and 10.83 d (specific growth rate, µ: 0.054 and 0.064 d-1) and 20.38 and 17.77 d (µ: 0.034 and 0.039 d-1) respectively. Also, strains WOD8 and WOIS2 grew on supplemented CWW and SWL with doubling times of 10.04 and 9.9 d (µ: 0.069 and 0.070 d-1) and 16.12 and 16.12 d (µ: 0.043 and 0.043 d-1) respectively. Similarly, the doubling times of strains WOB3 and WOB7 when grown on CWW and SWL (without supplementing mineral salts medium) were 8.25 and 7.53 d (µ: 0.084 and 0.092 d-1) and 8.66 and 9.90 d (µ: 0.080 and 0.070 d-1) respectively. Whereas, the same strains had doubling times of 6.30 and 5.78 (µ: 0.11 and 0.12 d-1) and 6.30 and 9.24 (µ: 0.11 and 0.075 d-1) respectively when grown on supplemented CWW and SWL. It would appear that CWW has the highest potential as a natural growth substrate than SWL, and its use for biomass production may contribute to a reduction in the overall environmental impact generated by discarding cyanogenic residues.Item 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.Item Genotoxicity Evaluation of Landfill Solid Waste Leachates from a Waste Dumpsite in Lagos State, Nigeria using the Allium cepa Assay(Plant and Animal Research Journal, 2018) Ogunyemi, Kayode A.; Samuel, Titilola A.; Amund, Olukayode O.; Ilori, M. O.The management of municipal landfill’s leachate is considered one of the most significant environmental issues. Potential mutagenic and genotoxic effects of solid waste leachates (SWL) were investigated using the Allium cepa root meristematic cells assay technique. In Allium root growth inhibition test, experimental onion bulbs were cultivated in various concentrations of the SWL and distilled water was used as a negative control. The root tips from the treated bulb were processedby orcein squash technique after 72 h. The mean lengths of root bundles were obtained andeffective concentration (EC) values calculated. Some of the physicochemical properties of the WL were also determined. The A. cepa assay was carried out at concentrations of 0.05, 0.1, 2.0, 5, 10, 20, 50 and 100% of the WL. There was a statistically different (p < 0.05), concentrationdependent inhibition of onion root growth and mitotic index, and induction of chromosomal aberrations in the onion test. The results of the physicochemical analysis revealed that the concentrations of some parameters were above the maximum permissible limit set by the world health organization (WHO) and could partly be correlated with the toxicity of wastewater. The landfill leachates pose a risk to human health and the environment in general. Hence, ecotoxicity/genotoxicity assays would be useful in leachate risk assessment when coupled with physicochemical analysis.Item NITRILE-METABOLIZING BACTERIAL STRAINS ASSOCIATED WITH MUNICIPAL WASTE TIPS IN THE LAGOS METROPOLIS, NIGERIA(UWM OLSZTYN, 2019) Ogunyemi, Adewale K.; Samuel, Titilola A.; Amund, Olukayode O.; Ilori, Matthew O.Cyanide is one of the dominant pollutants in the environment. This study aimed at exploring the potential of microbes in the detoxification of cyanogenic substances. Bacillus sp. WOD8 KX774193 and Corynebacterium sp. WOIS2 KX774194 strains were isolated from solid waste leachates. The doubling times of strain WOD8 and strain WOIS2 when grown on glutaronitrile and benzonitrile (without supplementing glucose) were 12.2 and 7.86 d (specific growth rate, μ: 0.057 and 0.088 d-1) and 15.75 and 13.33 d (specific growth rate, μ: 0.044 and 0.052 d-1) respectively. Also, strains WOD8 and WOIS2 grew on glutaronitrile and benzonitrile (with supplementing glucose) with doubling times of 9.76 and 7.62 d (μ: 0.071 and 0.091 d-1) and 10.5 and 8.15 d (μ: 0.066 and 0.085 d-1) respectively. The results from the present study suggest that the nitrile-metabolizing capabilities of these bacterial isolates can potentially be explored for the degradation and bioremediation of nitrile contamination in the environment.