Molecular characterization of some bacteria and fungi associated with the decomposition of leaf litters of Eucalyptus camaldulensis and Tectona grandis

Eucalyptus camaldulensis and Tectona grandis, have the characteristics of fast growth rate. The decomposition of litter biomass of these exotic plants is necessary in order to return the nutrients taken up by the plants. Some of the major nutrients include nitrogen, carbon, phosphorus, potassium, calcium and magnesium. To have a better understanding of the decomposition of leaf litters of E. camaldulensis and T. grandis, bacteria and fungi associated with their decomposition were investigated. Soil and leaf litters of these exotic plant species were collected from six sampling sites of each plantation designated as E1 – E6 for E. camaldulensis and T1 – T6 for T. grandis, respectively. Litterbag technique was employed for the decomposition study which lasted for 60 days. Using standard methods, analysis of carbon (IV) oxide evolution and microbial population were done at day 1, 30 and 60 of the decomposition period. Results showed that there was a general decrease in the percentage mass loss of E. camaldulensis and T. grandis leaf litter samples, which ranged from 71-85% and 40-61% respectively. The amount of carbon, nitrogen, phosphorus, potassium, calcium and magnesium decreased in the leaf litter but increased in the soil during decomposition. The evolution of CO2 was highest in E4 on day 60 (554.4 μg/g/day) among E. camaldulensis samples, whereas the evolution of CO2 was highest in T2 on day 30 with a value of 516.5 μg/g/day among T. grandis samples. The bacteria isolated during the decomposition periods were Bacillus licheniformis, Pseudomonas putida, Bacillus subtilis, Micrococcus luteus, Proteus vulgaris while fungi were Aspergillus niger and Penicillium notatum. Bacillus licheniformis was the most prevalent bacteria isolated. There is need to molecularly establish the specific capability of each microbial isolate with the view to identifying those that sequentially elaborate enzymes that can completely metabolize the leaf litters to their elemental form for adequate enrichment of the soil. This will enhance rapid recovery of the composite undergrowth and also promote diverse microbial colonization.Keywords: Decomposition, leaf litters, Eucalyptus camaldulensis, bacteria, fungi, and Tectona grandi

Isolation and Identification of Hydrocarbons- Degrading Bacteria from Panteka Stream, Kaduna, Nigeria, and Assessment of their Potential for Bioremediation

Water bodies become hydrocarbon-polluted when petroleum and other toxic organic matters are discharged into them. Panteka, located in northern Kaduna, Nigeria, is home to Panteka market, which is an industrial hub where different kinds of automobile spare parts are sold and mechanic workshops are situated. The Panteka stream flows through an entry point at Rafin guza, through Panteka market and towards the National Eye Centre. The indiscriminate disposal of spent engine oils and the discharge of other untreated effluents from car servicing workshops into the Panteka stream can lead to hydrocarbon contamination. Consequently, there is a need to identify these hydrocarbons and determine the capability of bacteria isolated from the stream to degrade the hydrocarbon pollutants. Using the pour plate method, and Bushnell Haas agar supplemented with 1% used engine oil, five bacterial isolates with the potential to degrade hydrocarbons were identified as Streptococcus pnuemoniae, Klebsiella pneumoniae, Shigella dysenteriae, Streptococcus pyogenes and Salmonella enterica. Salmonella enterica was confirmed by 16S rRNA gene sequencing and Basic Local Alignment search tool (BLAST) with a similarity index of 99%. The ability of the bacterial isolates to tolerate the spent engine oil was determined by turbidi metry. The results show that all the five bacterial isolates were able to tolerate the 1% (v/v) concentration of the spent engine oil. The highest growth rates (O.D 0.565 and O.D 0.695) were obtained from the pure cultures of Streptococcus pyogenes and the mixed bacterial consortium, respectively. The potentials of the bacteria to degrade hydrocarbons in the stream was analysed using Gas Chromatography Flame Ionization Detector (GC-FID), and the results showed reduction of the Total Petroleum Hydrocarbon (TPH) content from 6,056 mg/ml to 100.17 mg/ml (98.3% degradation) after 28 days of treatment with the mixed bacterial culture. The hydrocarbon fractions degraded were n-Nonane, n-Decane, n-Undecane, n- Dodecane, n-Tridecane, n-Tetradecane, n-Heptadecane, Pristane, n-octadecane, Phytane, n-Eicosane, n-Tricosane, n-Tetracosane, n-Octacosane, n-Triacontane, n-Dotriacontane, n-Tritriacontane, n-Heptriacontane; while n-Pentadecane, n-Hexadecane, n-Nonadecane, n-Heneicosane, n-Docosane, n-Pentacosane, n-Hexacosane, n-Heptacosane, n-Nonacosane, n-Hentriacontane, n-Tetratriacontane, n-Pentatriacontane, and n-Hexatriacontane were not degraded. This study shows that these bacterial strains isolated from the Panteka stream have great potential for bioremediation of the hydrocarbons found in the stream. Keywords: Bioremediation, Panteka stream, Automobile workshop, Hydrocarbon pollution, Bacteria isolate

Screening of Fungi Isolates from Kaduna Refinery Effluent and Romi River and Their Potential for Bioremediation

The operation of Kaduna Refinery and Petrochemical Company (KRPC) has increased effluent generation with consequent effects on water quality and habitat since it is discharged into nearby receiving water body. These effluents contain heavy metals and other toxicants. Samples were  collected from the effluent discharge point of the Kaduna Refinery and Petrochemical Company (KRPC) and from Romi River located at Kaduna South Local Government Area of Kaduna state. Standard methods were used to analyze the physicochemical parameters and heavy metals of the effluents. A total of 14 fungi isolates were identified from the samples. These fungi isolates were screened for their bioremediation potential on some toxic components in refinery effluent and were identified using molecular techniques. Four fungi isolates (Chrysosporium tropicum, Aspergillus flavus, Aspergillus niger and Rhizopus oryzae) were selected for bioremediation. Carbon (IV) oxide evolution increased progressively during the period of bioremediation. There was a noticeable decline in the phenol, lead, cadmium and nickel in the entire bioremediation medium. There was a positive correlation between phenol and cadmium with a coefficient of 0.969. Consortia of fungi isolated from the refinery effluent and Romi River samples were effective in the bioremediation of refinery effluent. The mixed consortium of four fungi showed the most efficacies in the bioremediation of refinery effluent in terms of phenol, oil and grease, cadmium, lead and cadmium reduction. Kaduna Refinery and Petrochemical Corporation (KRPC) should adopt bioremediation as one of the techniques in treating effluents before being discharged into receiving water bodies Keywords: Effluents, Fungi, heavy metal, bioremediation