Assessment of the potentials of Autochthonous lipase-producing bacteria in the treatment of palm oil mill effluent

Abstract

Pollution caused by the release of untreated palm oil mill effluent (POME) is a major environmental concern. This research assessed the potentials of single and consortium of
autochthonous lipase-producing bacteria as a non-invasive procedure in the biotreatment of
POME. The identity of lipase-producing bacteria in POME were determined using morphological and biochemical techniques. Identified isolates were monitored for POME utilization by measurement of optical density at 600 nm in 25 ml Bushnell Haas broth supplemented with 0.25 ml sterilized POME. Individual isolates and consortium were then used for the bioremediation of POME. Quality parameters including pH, total suspended solid (TSS), oil and grease, chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC), total organic matter (TOM) and total nitrogen (TN) of the raw and treated effluents were evaluated. The population (CFU/ml) of total heterotrophic, POME - utilizing and lipolytic bacteria were 3.9 x 106, 2.8 x 106 and 3.5 x 105 respectively. The lipolytic bacterial isolates include Brenneria nigrifluens, Bacillus circulans and Paenibacillus pectinilyticus. Results revealed varying pH of 5.03 and 6.81 - 7.26 for untreated and treated respectively. The lipolytic bacteria from POME caused reduction efficiency of 100% in TSS and oil and grease contents of the treated effluents relative to the raw samples. The COD, BOD, TOC, TOM and TN reduction ranged 17.90 - 93.55, 1.66 - 90.52, 16.34 - 59.79 %, 6.18 - 80.78 % and 11.71 - 93.66 % respectively. This research indicated that POME indigenous lipase-producing bacteria improved POME quality and therefore suggestive of their potentials in the bioremediation of POME-contaminated environment with the consortium being most effective.