The esterification catalyzation of crude lipase in glutinous rice bran varieties which are Korhor 6, Thanyasirin and Khawneawdum were investigated in isooctane as solvent. Free fatty acids from edible oil to use as substrate were prepared by hydrolyzation reaction with 8 molar potassium hydroxide for rice bran oil and 12 molar for olive oil and coconut oil. The moisture content of the rice bran had shown 8.52-10.13%, free fatty acid content shown 14.96-20.19% and total protein shown 31.57-76.20%.
The high esterification activities rate of rice bran lipase at 37 C were found in free fatty acid and butanol as substrate in 1.338 mole ratio at reaction time 30 minutes in water saturated isooctane as solvent. The composition of fatty acid butyl ester were detected by gas chromatographic technique which indicate that the specification of lipase to saturated and unsaturated of short chain to long chain fatty acids.
Keywords : Esterification activity, Lipase, organic solvent