BIODEGRADATION OF FATS, OIL AND GREASE USING MICROORGANISMS ISOLATED FROM PALM OIL MILL EFFLUENT

The biodegradation of fat, oil, and grease (FOG) is important in water pollution control and wastewater management. In this study, the viability of FOG-degrading microorganisms on palm oil biodegradation was assessed. Seven strains capable of degrading FOG were isolated from palm oil mill effluent (POME). The potential bacterial strains were selected based on Tween-80-degrading ability. Micrococcus lylae strain DSM 20315 showed the highest growth compared to the other strains. Hence, it was selected for FOG degradation test. The biodegradability was performed as a function of pH (6, 7, 8), initial oil concentration (1, 3, 5% v/v), and inoculum concentration (2, 6, 10% v/v). Optimization of these parameters of palm oil degradation was studied using 2-level factorial design. The maximum oil degradation was 68%, obtained at pH 6, initial oil concentration 1 % v/v, and bacterial inoculum concentration of 10 % v/v. The lowest oil degradation obtained was 22%. The initial oil concentration followed by bacterial inoculum concentration enhanced the removal efficiency of FOG, but the pH level did not significantly promote the degradation rate. As a result, the optimum process conditions for maximizing oil degradation were at pH 6, initial oil concentration 1 %v/v, and bacterial inoculum concentration of 10 %v/v. ABSTRAK:  Biodegradasi lemak, minyak, dan gris (FOG) adalah penting dalam kawalan pencemaran air dan rawatan air buangan. Kajian ini adalah berkenaan kebolehhidupan organisma pengurai-FOG dalam biodegradasi minyak kelapa sawit. Tujuh strain berkeupayaan mendegradasi FOG diasingkan daripada cairan buangan minyak kelapa sawit (POME). Strain bakteria yang berpotensi telah dipilih berdasarkan keupayaan degradasi-Geladak-80. Strain Mikrokokus lilae DSM 20315 menunjukkan pertumbuhan tertinggi berbanding strain lain. Oleh itu, ia dipilih bagi ujian degradasi FOG. Keupayaan biodegradasi telah dihasilkan berdasarkan fungsi pH (6, 7, 8) ketumpatan  awal minyak (1, 3, 5% v/v) dan ketumpatan inokulum (2, 6, 10% v/v). Parameter optimum degradasi minyak kelapa sawit dikaji menggunakan reka bentuk faktorial 2-tahap. Nilai maksimum degradasi minyak adalah sebanyak 68%, terhasil pada pH 6, berketumpatan awal 1% v/v, dan ketumpatan inokulum bakteria 10% v/v. Degradasi minyak terendah pula adalah sebanyak 22%. Ketumpatan awal minyak diikuti ketumpatan bakteria inokulum meningkatkan kecekapan penyingkiran  FOG, tetapi level pH tidak ketara dalam membantu kadar degradasi. Sebagai kesimpulan, keadaan optimum bagi degradasi minyak maksimum adalah pada pH 6, ketumpatan awal minyak 1% v/v dan ketumpatan bakteria inokulum sebanyak 10% v/v.