Microbial Diversity and Lipolytic Activity of Bacteria and Fungi from Oil-Contaminated Sites in Makurdi Metroplois

Lipases are vital biocatalysts with extensive industrial and environmental applications. This study aimed to isolate and screen lipase-producing bacteria and fungi from oil-contaminated sites in Makurdi metropolis, Nigeria. A total of 47 microbial isolates, comprising 28 bacteria and 19 fungi, were recovered from seven selected sites. The bacterial isolates included Bacillus spp., Pseudomonas aeruginosa, Staphylococcus aureus, Enterobacter spp., Flavobacterium spp., Streptococcus spp., and Bacillus subtilis. The fungal isolates included Aspergillus spp., Penicillium spp., Rhizopus spp., Mucor spp., and Neurospora spp. Lipolytic activity was assessed using Tween 80 agar and Phenol Red Olive Oil Agar. All isolates exhibited varying degrees of lipase production (p˂0.05), as evidenced by clear zones around colonies. Among the bacterial isolates, Bacillus spp. demonstrated the highest lipolytic activity on Tween 80 agar, with clearance zones ranging from 44 mm to 62 mm. Pseudomonas aeruginosa and Staphylococcus aureus also exhibited significant activity, with peak clearance zones of 58 mm and 55 mm, respectively, at 120 hours. On Phenol Red Olive Oil Agar, Flavobacterium spp. showed the lowest lipase activity (5-9 mm), while Pseudomonas aeruginosa and Enterobacter spp. recorded moderate activity (4-8 mm). Among the fungi, Neurospora spp., Aspergillus flavus, and Aspergillus niger exhibited the highest activity, with clearance zones up to 83 mm. These findings highlight the potential of indigenous microbial strains for biotechnological applications, including bioremediation and industrial enzyme production. Further optimization