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-Orange fruits from two seasons, in April and August 2006 representing late 2005 and early 2006 harvests respectively were cured in hot air at 36-37 0 C to 1%, 3%, 5% and 7% weight loss before storage at 28 0 C and 86% relative humidity (RH). The fruits were observed for incidence of decay, further weight loss, juice content, firmness or softening of the peel, total soluble solids (TSS), pH, titratable acidity, and colour during storage. Curing reduced the incidence of decay. All control fruits were rotten by day 21 in August harvest while 22.5% of the control was rotten by day 56 in the April harvest. Storage life was extended beyond 56 days in fruits cured with 1, 3, 5 and 7% in April harvest as there was no decay throughout, while decay incidence in August harvest was 88.9, 61.1, 22.2 and 31.3% in 1, 3, 5 and 7% respectively. Penicillium digitatum, Phytophthora sp., Alternaria citri and Collectotrichum gloeosporioides were among decay causing moulds detected. Control fruits lost more weight during storage than cured fruits did. Fruit rind hardening was more noticed in the control and those cured to 1% weight loss, especially from the April harvest. It was insignificant in other treatments in both trials. Titratable acidity, pH, juice content and TSS were not affected by the treatment. Colour change to yellow was however retarded by curing. Curing to 5% weight loss was best for decay control and quality retention.

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In vitro degradation of bitumen by microorganisms isolated around bitumen deposit at Agbabu was investigated. The microorganisms were isolated from soil sample collected around bitumen deposit and bitumen itself. The ability of individual isolates to utilize bitumen as sole carbon source in mineral salt medium was investigated. The results showed a decrease in the pH of the medium with an increase in the bacteria cell densities within the period of incubation, thereby confirming activities of the isolates in the medium. Bacillus subtilis (29.15%) caused highest weight loss from the bitumen, while Pseudomonas aeruginosa (12.03%) caused the least among the bacteria isolate. Other bacteria isolated were Acinetobacter sp. and Staphylococcus aureus. All the isolates caused weight loss from the bitumen. For moulds, Arthrobotrys oligospora caused higher percentage weight loss (19.13%), than Aspergillus niger in 28 days of incubation. By the 56 days of incubation, Bacillus subtilis was responsible for highest weight loss (49.50%), while Pseudomonas aeruginosa exhibited the lowest percentage (23.17%). For the moulds, Arthrobotrys oligospora caused the higher weight loss (42.83%) while Aspergillus niger had 37.33%. Thus, this established that the microorganisms isolated from the soil around the Agbabu bitumen and the bitumen itself could degrade bitumen from tar sand, hence their potential usefulness in remediation of bitumen polluted environment when the exploitation of the resource commenced. Keywords: Bitumen; Bacteria; Mould; Hydrocarbon

Background Alteration in the normal composition of gasses in the atmosphere referred to as air pollution can occur as a result of different processes, including emissions from vehicles and power generators. Gasses affect living things directly and indirectly by playing roles in respiration, membrane function, synthesis, and growth. The gasses contained in fumes emitted from vehicles and generators may likely have effect on microorganisms in the environment including microfungi. Two microfungi were selected to study the effect of generator emissions on their growth. Results The gaseous emissions from power generators fueled by gasoline caused reduction in spore germination and germ tube lengths of R. stolonifer and F. oxysporum. For the former, spore germination decreased with length of exposure after an initial increase by ~ 100%. The fungus exhibited a single major germination peak at 10 min and a minor one at 30–35 min exposures. Germ tube length of the fungus also decreased with increased exposure. F. oxysporum too showed reduced spore germination and germ tube length with exposure but the fungus seemed to adjust better to the unfavorable environment created by emitted gasses showing multiple peaks of reduced heights as time progressed, though another rise that could reach a peak appeared at the 45-min maximum exposure for germ tube length. The peaks were however more broad for spore germination experiments indicating more stability in adjustment than observed for germ tube length. Greatest reduction in spore germination was by 25% in R. stolonifer and 71% in F. oxysporum Germ tube length reduction for R. stolonifer was by 24–76%, the greatest occurring at 35-min exposure, while for F. oxysporum it was 5–83%, the greatest occurring at 40 min exposure. Conclusions These observations reveal the toxicity of the gasses emitted to the growth of the two filamentous fungi and the potential harmful effect to other fungi which might be useful in the ecosystem as decomposers and to those that may be pathogenic to higher plants.