Treetippa Laohaprapanon, Poonsuk Prasertsan, and Aran H-Kittikul

pp. 801 - 808

Abstract

The characteristics of palm oil mill wastewater (POMW) were brown color, pH 3.8-4.3, temperature48-55°C, total solids 68.2-82.1 g/l, suspended solids 26.2-65.6 g/l, oil and grease 19.1-25.1 g/l, COD 49.9-160.7g/l and BOD 32.5-75.3 g/l. After centrifugation (3,184 xg) of 50 ml POMW for 10 min, the POMW was separated into 3 layers: top (oil), middle (supernatant) and bottom layer (sediment). The sediment contained dry weight 1.19 g and oil and grease 1.07 g. In order to release oil and grease trapped in palm fiber debris in the POMW, cellulase- and/or xylanase-enzyme-producing and thermotolerant microorganisms were isolated. The isolates SO1 and SO2 were isolated from soil near the first anaerobic pond of the palm oil mill. They were aerobic, Gram positive, rod shaped, thermotolerant microorganisms and produced cellulase 12.11 U/ml (3 days) and 7.2 U/ml (4 days), and xylanase 50.98 U/ml (4 days) and 20.42 U/ml (4 days), respectively in synthetic medium containing carboxymethycellulose as a carbon source. When these 2 isolates were added
into the steriled POMW under shaking condition for 7 days, after centrifugation at 3,184 xg the isolate SO1 gave the better % reduction of dry weight (64.66 %) and of oil and grease in the bottom layer (85.32 %) of the POMW.