Effects of Palm Oil Mill Effluent on Nitrogen Fixing Bacteria

ABSTRACT A good quality soil is characterized by adequate nutrients as a result of abundant nutrients cycling bacteria. Most soil in Nigeria has been subjected to different kinds of pollutants resulting from anthropogenic activities which have become a major threatening factor to the quality of soil. This study was carried out to evaluate the effects of palm oil effluent on nitrogen fixing bacteria. A total of 30 composite soil samples were aseptically collected from palm oil mill effluent sites at Uli community using a sterile soil auger. The samples were analyzed for Nitrogen fixing Bacteria (NFB) and Total Heterotrophic Aerobic Bacterial Count (THABC) using standard plate technique. The predominant bacterial isolates that aided nutrients cycling were appropriately characterized, and their densities in both impacted and non-impacted soil samples were enumerated. Also, the bacterial isolates were characterized based on morphology, microscopy, and biochemical characteristics. There was an increase in the NFB and THABC in the impacted soil, and Gram negative rods such as Pseudomonas and Klebsiella species and Micrococcus species (Gram positive) were the bacterial isolates. The study has revealed that palm oil effluent in the soil increases a microbial activity which invariably increases soil fertility.