Stutzerimonas stutzeri- A potential candidate for the bioremediation of fried cooking oil waste

This study explores the bioremediation potential of bacterial isolates derived from soils contaminated with fried palm olein oil. Molecular identification of isolates from fifteen soil samples revealed the presence of Stutzerimonas stutzeri , Bacillus licheniformis , Paracoccus spp., Acinetobacter baumannii , and Enterobacter hormaechei . Biofilm-forming capabilities were assessed using the tube adherence test and microtitre plate assay, with biofilm visualization conducted via fluorescent staining on coverslips. The isolates' capacity to degrade Fried Cooking Oil (FCO) was evaluated using emulsification index (EI24%), gravimetric analysis, lipase activity assays, and Fourier Transform Infrared Spectroscopy (FTIR). Stutzerimonas stutzeri demonstrated the highest emulsification activity (EI24% = 55.55 %) and oil degradation efficiency (76.74 %) in gravimetric analysis. The strong biofilm formation observed contributed to the degradation efficiency. FTIR analysis showed minimal alterations in FCO functional groups post-treatment. Oil degradation was found to be independent of the Gram nature of the isolates. These findings underscore the potential of Stutzerimonas stutzeri in developing eco-friendly strategies for the bioremediation of FCO-contaminated environments. • Identification of Key Palm Olein-Degrading Bacteria: Five bacterial species including Stutzerimonas stutzeri, Acinetobacter baumannii, Enterobacter hormaechei, Bacillus licheniformis, and Paracoccus species, were successfully isolated and identified from palm olein-contaminated sites. • Superior Biofilm Production and Degradation by Stutzerimonas stutzeri: Stutzerimonas stutzeri demonstrated strong biofilm formation and exhibited high emulsification (EI24% of 55.55%) and significant oil degradation (76.74% by gravimetric analysis). • Microbial Influence on Oil Chemistry: FTIR analysis revealed minor alterations in the functional groups and unsaturation of fried cooking oil (FCO) attributed to microbial action, indicating changes in oil composition post-degradation.