生物修复与生物降解杂志

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Effect of Physical Parameters on Biodegrading Activities of Some Bacteria Isolated From Spent Motor Oil Contaminated Soil at Umuahia, Abia State

Stephen AC, Nwakanma CC, Mbagwu CF

Indiscriminate discharge of spent motor oil (SMO) in the environment has become major environmental contaminants as they contain polycyclic aromatic hydrocarbon (PAHs) which are extremely toxic, carcinogenic and mutagenic to human, animals, and plants. Consequently, the need to expand economical and practical remediation technologies for spent engine oil contaminated sites is evident. The study assessed the effect of temperature and pH on biodegrading activities of bacteria isolated from the study area was assessed. Soil sample were collected from the study area from a depths 0 cm-20 cm using a hand held auger instrument to isolate hydrocarbon utilizing bacteria using serial dilution method. The influence of temperature (20°C, 30°C, 40°C, 50°C) and pH (5.5, 6.5, 7.5 and, 8.5) on degradation of spent engine oil by the bacterial isolates was studied. Each strain was incubated in mineral salts media supplemented with 2% spent engine oil. The bacterial culture was inoculated in conical flaks containing 100 mL of broth oil mineral salts media. Control conical flasks containing the same amount of MSM and spent engine oil but without bacterial culture were prepared. All flasks were incubated for 28 days. N-hexane was used to extract the residue oil. The optical density was read at 600 nm wavelength with UV-Visible spectrophotometer. The pH was adjusted at 5.5, 6.5, 7.5 and 8.5 using 1 N HCl/1 N NaOH. The result of the study reveal that fifteen bacteria genera were isolated and identified by biochemical technique from the study area and the effect of temperature and pH on biodegradation of spent engine oil revealed that the bacteria isolates gave the best degradation at 30°C-40°C and at a pH range of 6.5-7.5.