Studies on petroleum-degrading potentials of wild and mutant strains of bacillus sp isolated from an oil-contaminated soil in Abraka, delta state, Nigeria

Petroleum degrading potentials of Bacillus sp isolated from an oil-contaminated soil was determined in the laboratory through growth in 5% Automated Gas Oil-supplemented minimum basal media at room temperature (30 ± 20C). Pure cultures of Bacillus sp were then subjected to mutation using 0.01%, 0.1%, 1% and 10% nitrous acid and by exposure to X-rays for 2 and 5 seconds and their petroleum degrading potentials were determined for 7 days. It was observed that both the parent and mutants degraded petroleum with the nitrous acid mutants possessing varying increased potential than the parent stock. F-tests at 95% confidence level showed significant differences in total aerobic counts and pH. There were no significant differences in temperature between parent and mutants in both treatments. Thus, while both nitrous acid and Xrays could initiate mutation in Bacillus sp, only the nitrous acid mutants possessed the desirable greater potentials to degrade the petroleum product and could thus be employed in the bioremediation of petroleum or its products

Screening of fungi isolated from Kaduna refinery area for petroleum hydrocarbon bioremediation potentials

Bioremediation relies upon microbial enzymatic activities to degrade the offending contaminants. The aim of this study was to isolate and screen fungi from a Petroleum refinery environment for oxidase enzyme. Soil, effluent, surface water, sediment and ground water samples were analysed for hydrocarbon utilizing fungi (HUF). The HUF were isolated by the standard plate count method and the hydrocarbon vapour phase transfer technique. Oxidase enzyme activity was determined spectrophotometrically with acetaldehyde as substrate. Sixty fungi were isolated. Out of the 60 fungal isolates 52 (87%) were positive for oxidase enzyme. The colonial and microscopic characteristics indicated that the probable fungi from the sites were Penicillium, Fusarium, Aspergillus flavus Monilia, Cephalosporium, Verticillium, Phytophora, and yeast. Penicillium and Fusarium were the dominant fungi. The results of the oxidase enzyme activity indicated that majority of fungi in the study site possessed the ability to transform or degrade, contaminants

Studies on the physicochemical characteristics and bioremediation potentials of surface water and effluent in Kaduna refinery environment

Petroleum operations are potential sources of environmental pollution capable of contaminating rivers which pass through the industrial areas and consequently affect human health. Hence there is need for bioremediation interventions. The aim of this study was to provide data on the physical and chemical characteristics of surface water and effluent in the study area which could be used for bioremediation strategy in the area. Surface water and effluent samples were analysed for physicochemical parameters using standard methods. The surface water and effluent were acidic. Temperature was found to be within the range favourable for bioremediation. The dissolved oxygen (DO) is not limiting for bioremediation. Electrical conductivity and chloride were high. Low levels of nitrate nitrogen (0.30 – 2.42mg/L) observed are limiting for bioremediation. The effluent and Romi River downstream had BOD greater than the allowable limit (10mg/L). Biostimulation is recommended as bioremediation strategy in the site

Evaluation of phytochemical and antibacterial properties of Terminalia avicennioides crude extract against selected bacteria from diarrhoeic patients

Phytochemical screening of aqueous and ethanol crude extracts of the different plant parts of Terminalia avicennioides was carried out using standard chemical evaluation methods. The antibacterial effects of aqueous and ethanol crude extracts of Terminalia avicennioides against E.coli and S.typhimurium clinical and reference isolates from diarrhoeic patients were also evaluated using agar-well diffusion method. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of aqueous and ethanol crude extracts were evaluated by broth dilution techniques. The result revealed the presence of carbohydrates, alkaloids, tannins, flavonoids saponins, triterpens and glycosides. All bacteria were found to be susceptible to the extracts which were indicated by the various zones of inhibition. The activity of extracts was concentration dependent. The reference strains were less susceptible to all extracts at low concentrations of 12.5mg/ml, but highly susceptible to extracts at varied concentrations of 25, 50 and 100mg/ml. However, all test bacteria were more susceptible to the ethanol extracts compared to the aqueous extracts with mean zones of inhibition ranging between 0.68 + 2.54 mm to 22.08 + 1.75 mm on E. coli clinical isolates, 0.0 + 0.0 mm to 20.00+0.mm on E. coli reference isolate, 3.08 + 6.0 mm to 21.50 + 0.00 mm on S. typhimurium clinical isolates and 0.00 + 0.mm to 20.00 + 0.0 mm on S. typhimurium reference isolate. The ethanol crude extracts exhibited lower MICs (12.5 to 25mg/ml) and MBCs (25 to 50mg/ml) values indicating higher efficacy of ethanol extracts, with the leaf extract demonstrating the highest activity against all the bacterial isolates. The important bioactive compounds present in the plant may be responsible for the observed antibacterial activity of the plant and hence its potential use as an antibacterial agent.Keywords: Phytochemical, Antibacterial effect, Terminalia avicennioides, diarrhoeaic patients

Phylogenetics of aflatoxigenic moulds and prevalence of aflatoxin from in-process wheat and flour from selected major stores within northern Nigeria

Aflatoxigenic strains that produce aflatoxins may be similar morphologically but vary genetically. Sequenced aflR-1 gene from this work was used to study relatedness of aflatoxigenic strains. Yeast extract sucrose agar (YESA) supplemented with 0.3% cyclodextrin and 0.6 % sodium Desoxycholate (YCSD) was used to characterize aflatoxigenic moulds. Total aflatoxin content of the samples was determined using Enzyme Link immunosorbent assay (ELISA). Multiplex PCR was carried out on aflatoxigenic and some non aflatoxigenic moulds using the genes; aflR-1, omt-A, ver-1 and nor-1. The aflR-1 PCR products were sequenced and used for Basic Alignment Search Tool (BLAST) and to generate dendogram. While the raw wheat samples presented highest total aflatoxin range 0.6 – 49 μg/kg, major stores presented values of 0.50 – 28 μg/kg, higher than that obtained in-process samples (0.70 – 26 μg/kg). However, there was no significant differences (p≥0.05) between the major store total aflatoxin levels and that of in-process samples. Thirty seven (37 %) and 25 % of the wheat flour samples from in-process and major stores respectively exceeded the 10 μg/kg National Agency for Food and Drug Administration and Control, Nigeria (NAFDAC) recommended limit for this product. Thirty six (36 %) and 21 % prevalence of wheat and wheat flour samples respectively analyzed from this work was contaminated with total aflatoxins. The multiplex PCR response from this work has demonstrated that there was consistency in the banding pattern of aflatoxigenic strains with respect to the major aflatoxin biosynthetic genes from this study. BLAST of the assembled AFL2T gene sequences was found to have compatibility with that of standard aflR-1 of NCBI Gene Bank that also created way of identifying the isolates. The bootstrap similarity matrix differentiated the isolates into two major clusters; sub-group and others assembled together indicating closer relatedness or general similarity. Some of the isolates varied greatly with visible mixtures of aflatoxigenic and non aflatoxigenic moulds and also random distribution of in-process and store isolates at different leaf nodes within the major clusters. Awareness and surveillance of aflatoxin levels by processors and regulatory bodies at raw material intake is advocated.Keywords: Moulds, Aflatoxin, Gene, Dendogra

Bioconversion of cassava starch to ethanol in a simultaneous saccharification and fermentation process by co-cultures of Aspergillus niger and Saccharomyces cerevisiae.

Ethanol production by co-cultures of A. niger (GS4) and S. cerevisiae (BK6) was studied using cassava starch as substrate. At 1% substrate concentration ethanol yield was 0.35g/100ml while the ethanol concentration increased to a maximum of 3.60g/100ml at 8% substrate concentration. When the culture conditions were optimized, the ethanol yield further increased to 4.30g/100ml at a temperature of 35oC, pH 5.0, 300rpm agitation rate and reduced fermentation period of 4 days. Keywords: A. niger, S. cerevisiae, Fermentation, Ethanol, Cell dry weight, Residual suga

Physicochemical quality of drinking water from various water sources of Kaduna state, Nigeria

This study was undertaken in six Local government areas (LGA) of Kaduna from  March 2014- February 2015, with the aim of determining some physicochemical parameters of water being used by residents in the study areas. The results were also  compared with the World Health Organization (WHO), Nigerian Institute of Standards (NIS) permissible limits for all the   parameters. A total of fifty samples from different water sources were analysed for the following parameters: Biological Oxygen Demand (BOD5), Dissolved oxygen, Total Dissolved Solids (TDS), Nitrate, Electrical conductivity and pH using standard  methods. The values for conductivity (441.57 ± 107.13μhos/cm) and TDS (220.78 ± 53.56mg/l) were significantly higher for the borehole water samples (P<0.05), while the pH (7.27 ± 0.11) and nitrate (15.38 ± 1.29mg/l) values were significantly higher  during the rainy season (P<0.05). All the samples tested had their nitrate values less than the maximum level stipulated by both the NIS and WHO. Ninety-six percent of the samples had their pH and TDS within the recommended range (6.5-8.5 and 500mg/l  respectively). For the conductivity, the WHO standard differs from the NIS standard, and 60% met the WHO standard while 96% met the NIS standard.Key words: Potable water, Physicochemical parameters, season, WHO, NI

Occurrence and antibiogram of Staphylococcus aureus in dairy products consumed in parts of Kaduna State, Nigeria

total of 160 dairy products comprising of 80 each of fresh milk and ‘Nono’  (Fermented and defatted) were collected. The samples were cultured and identified by routine bacteriological methods. Prevalence of S.aureus (8.75%) in the products was; for fresh milk 3.75% and ‘Nono’ 5%. The susceptibility profile of the isolates to nine antimicrobial agents revealed a high susceptibility to Gentamicin (100%),  Ciprofloxaxin (92.86%) and Chloramphenicol (92.86%). The isolates had high resistance to Tetracycline (85.71%), Cefoxitin (64.29%), Amoxicillin/Clavulanic acid (64.29%) and Erythromycin (64.29%). A total of 9(64.29%) isolates were resistant to multiple antibiotics. Multiple antibiotics resistance index (MARI) ranged from 7.14% (0.7) to 21.43% (0.3). The presence of S.aureus and resistance to commonly used antibiotics by the isolates posses a health risk for consumers of these milk products.Key words: Dairy Products, Staphylococcus aureus, susceptibility profile, fresh milk, ‘Nono’

Determination of the genetic marker of the mutagenized strains of pseudomonas aeruginosa and bacillus cereus isolated from effluent of petroleum refinery

Bacillus cereus and Pseudomonas aeruginosa were isolated from the effluent of the Kaduna refining and petrochemical company, using standard methods. These were UV-irradiated for 30mins and thereafter subjected to nitrous acid treatment. Determination of essential amino acids required by both parents and mutants for growth showed that the mutant of Pseudomonas aeruginosa did not require valine and histidine for growth. The mutational treatments resulted in a sense mutation with beneficial effects of increased petroleum degradation. The amino acids requirement for growth could thus be used as a genetic marker for organisms that are subjected to mutational treatments

Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: A systematic analysis for the Global Burden of Disease Study 2015

Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods: We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings: Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation: Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding: Bill & Melinda Gates Foundation