Journal of Advances in Biology & Biotechnology

This study evaluated the potential of fungal isolates for laccase production. Fungi cultures were screened for laccase production on plate assay using 2’ 2’ – azinobis-(-3-ethyl benzthiazoline -6- suphonate) (ABTS), and by submerged fermentation. Result obtained from the plate assay showed the formation of green halo after 2-4 days of incubation due to oxidation of 2’ 2’ – azinobis-(-3-ethyl benzthiazoline -6- suphonate) (ABTS) which is as a result of lignolytic enzymes production Utilization of selected agro-wastes residues (sawdust, plantain and banana peels) for laccase production was evaluated. Fungal isolates were identified based on their cultural characteristics according to standard mycology methods. Light microscopy was performed on cultures and the fungal isolates were identified by their different morphological and colonial characteristics after which they were confirmed using fungal atlas. Total protein content was also determined using the Bradford method Five out of twelve isolates were positive for oxidation of 2’ 2’ – azinobis-(-3-ethyl benzthiazoline -6- suphonate) (ABTS) which signifies laccase enzyme activity and identified as Geotrichum spp, Cephalosporium spp, Trichoderma spp, Trametes spp and Fusarium sppThe highest enzyme activity was observed using Trichoderma spp at 57.1U/l, Trametes spp 51.99 U/l, Fusarium spp had 29.2 U/l. Geotrichum spp and Cephalosporium spp were least at 28.04 U/l and 9.72 U/l respectively. Trichoderma spp was used for further studies. Effect of carbon sources, inoculum size, pH, total protein and shaker speed on laccase production was evaluated. Sawdust gave the highest yield of laccase enzyme 151.17U /l, followed by plantain peel with 62.49U/l of enzyme, banana peel recorded the least of laccase enzyme 54.94 U /l. Protein content obtained from sawdust medium was 45.8mg/ml, plantain peel medium had 29.2 mg/ml while banana peel was the lowest with 16.8mg/ml all at the sixth day of the fermentation process. Optimum pH for sawdust, banana peel and plantain peel was 5.95, 5.94, and 5.83 respectively. Using shaker incubator (150 rpm) with sawdust as carbon source, laccase yield of (310.45U/l) was obtained at pH 6, temperature 25°C and inoculum size of 10⁵ spores per ml. Thus, sawdust can be categorically stated to be safe, cheap and could be suggested for prospective application of higher production of laccase enzyme in various industries.

The liquid-liquid extraction of Petroleum contaminated surface water samples were conducted in accordance with standard procedure of US EPA. Identification and quantification of TPHs was performed by Gas chromatograph with Mass spectrometric detection (GC/MSD) in accordance with standard analytical method of US EPA 8270;625. The TPHs raw sample showed an elevated value of 104762.42 mg/L above the DPR/EGASPIN maximum contamination limit (MCL). At week 5, TPHs phytoremediations in the monoculture reactors removal efficiency was (31.28 mg/L) 99.97% and mixedculture indicated (19.72 mg/L) 99.98%; their concentrations were above DPR/EGASPIN MCL while polyculture indicated (8.91 mg/L) 99.99% value was below DPR/EGASPIN MCL. The combination of phytoremediation and vermiremediation techniques in polyculture reactors showed better and spectacular results as the biotas demonstrated good potentiality of hyperbioaccumulation to serve as hydrocarbon sinks from the ecotoxics of TPHs.

Oil extraction operations as well as equipment failure and infrastructure vandalism have caused serious environmental pollution with crude oil spills world-wide. The remediation of the polluted sites is an environmental problem beckoning for solution. In this study, the possibility of pig droppings and pig bone char mixture (biostimulant) to stimulate and optimize crude oil biodegradation in soil was investigated. Exactly 500g of loamy soil was spiked with 3% (w/w) of crude oil. The spiked soil was amended with varying percentage mixtures of the biostimulant and labelled A – E. The spiked soil without biostimulant served as the Control. Each experiment was setup in six (6) replicates, carried out for six weeks, and destructively sampled and analysed on a weekly basis. The removal efficiencies of the biostimulated and unbiostimulated soils were observed to range from 66.70 to 86.70% and 3.69%, respectively. The biodegradation first-order rate constants ranged from 0.1978 to 0.3391wk^-1 and 0.0050wk^-1 for the biostimulated and unbiostimulated soils, respectively. Optimum removal of total petroleum hydrocarbon (TPH) was observed for biostimulated soil C comprising 50% bone char and 50% pig droppings. Results from biostimulated soils A, B, D and E indicated that pig droppings is a more effective biostimulant than pig bone char. A first-order kinetic model adequately predicted the removal of TPH with the optimum biostimulant. It is concluded that using agro-organic waste materials such as pig droppings and pig bone char in a ratio of 1:1 can offer a simple, effective, inexpensive and environmentally friendly solution to the problem of soil contamination with crude oil.

This study evaluated the efficacy of activated carbon from rice husk, corn cob and coconut husk wastes in the reduction of microbial properties of grey water samples harvested from students’ hostels. Microscopic characterization, enumerations and identification of microbial isolates were carried out to determine the microbial community before and after the treatment with activated carbon.  Staphylococcus sp, Micrococcus sp, Bacillus sp, Salmonella sp, Saccharomyces sp and Penicillium sp were observed to be present in the grey water. Before treatment, Total Heterotrophic Count (THC) was 1.2 x 10¹¹cfu/ml, Total Coliform Count (TCC), 6.4 x 10⁶cfu/ml and Total Fungi Count (TFC) 2.2 x 10¹⁰cfu/ml. THC after the treatment ranged from 1.69 x 10⁹ - 7.6 x 10¹⁰cfu/ml; TCC, 2.2 x 10⁵ - 7.3 x 10⁸cfu/ml and TFC 1.0 x 10⁸ - 1.2 x 10⁹cfu/ml. Reduction in the microbial load after treatment revealed that activated carbons from rice husk, corn cob and coconut husk can be used singly or in combined states for the treatment of wastewater.

Ethical issues arise when arable agricultural land and heavy agronomic inputs are used to cultivate crops for energy production such as biodiesel. Alternative feedstocks for biodiesel production might solve the food energy competition scenario. White raffia larvae (Rhynchophorus phoenicis) appears as a credible option because of its high lipid content, a relatively short life cycle and its abundance in the tropical environment. This study investigated the use of R. phoenicis larvae for biodiesel production. R. phoenicis larvae was grown on raphia stipe for 21 days and used for crude grease extraction. The extracted crude grease was converted into biodiesel by acid-catalyzed esterification and alkaline-catalyzed trans-esterification. The physicochemical properties of crude grease and biodiesel were investigated using the European biodiesel standard (EN14214), and the American Society of Testing materials specifications. The defatted extraction residue was analyzed using the AOAC protocol. Results revealed that the cetane number, heating value, acid value and density of crude grease were found to be higher than those of rapeseed while kinematic viscosity and iodine values were smaller. The conversion yield of free fatty acids of crude grease into biodiesel reached 85%. The fuel properties of biodiesel obtained are quite comparable with those of EN 14214 and ASTM standard. The defatted extraction residue exhibited high protein content (66,76%) and mineral which make it suitable for animal and human feed supplement. Therefore, it was concluded that, the R. phoenicis larvae can be used as valuable feedstock for biodiesel production and animal feed resources.