Screening and Isolation of Spent Engine Oil Degrading Microbes for Enhanced Biodetergent Production

ABSTRACT Spent engine oil degrading microorganisms has recently gained interest in the industrial sector for the purpose of producing biodetergent which serves as an alternative to other harmful surfactant which possess hazardous effect on humans and the environment. In this present study, an investigation was carried out on the presence of bacterial and fungal strains that have the ability to degrade spent engine oil as their main source of carbon. A total of three (3) different environmental samples were collected from three (3) different locations within Ikwo Local Government Area Ebonyi State and screened for the presence of degrading microbial species. Bacterial and fungal isolates were obtained using Mineral Salt Agar and Potatoes Dextrose Agar respectively. Isolates were further screened on Potatoes Dextrose Agar, resulting in the selection of sixteen (16) isolates based on their appearance on the culture media after incubation. Total viable counts of microorganisms in the samples ranges from 1.5× 10¹ (highest count) and 1.0 × 10¹ (lowest count) for the bacterial isolates and 2.2 ×10³ (highest count) 5.6× 10² (lowest count) for the fungal isolates. The ability of these isolates to degrade spent engine oil was determined using the gravimetric analysis method. From the morphological and biochemical tests taken, it was suspected that the bacterial isolate ( SA1, SA2, SB4 and SC3) as Bacillus sp.,(SA3, SB1, SC4) as Escherichia coli sp., (SA4) as Klebsiella sp., (SB2, SC2) as Staphylococcus sp., and (SB3 and SC1) as Pseudomonas sp.,while the fungal isolates (SA5, SA6, SB5, SB6) were suspected Aspergillus sp., and (SC6) Rhizopus sp. Isolated microorganisms can further be cultivated in a bioreactor to produce enzyme which is purified, lyophilized and introduced during the manufacturing of biodetergents, which can help reduce the environmental and human health issues that have been induced by chemically used laundry detergent. Keywords: Screening, isolation, characterization, Spent Oil degrading microorganisms, Biodetergents.