~iPseudomonas~i sp. KLB1 can produce lipase with growth associate pattern in the medium containing 1% (v/v) palmolein as carbon source and inducer at pH 7.0. The activity of this 1,3 specific lipase was 72.10 Unit/ml. The enzyme exhibited high activity in alkaline pH ranges, with optimal hydrolysis activity at pH 9 and 50(+,ฐ)C. Stability was highest at pH 7 and 37(+,ฐ) C while 24% of the hydrolysis activity was lost after being kept at 70(+,ฐ) C and pH 10 for 1 hr. The activity wasstimulated by chloride salts of Ca('2+), K% and Na('+), (NH, (,2)S(,2)O(,3) and ascorbic acid. The enzyme was found to be specific not only for palmolein but also for olive oil, fish oil, and soybean oil. Furthermore, the enzyme showed a higher affinity for palmolein (Km 110.9 mM) than for tributyrin (Km1,188.8 mM) but higher hydrolysis efficiency for tributyrin (Vmax 5.25 mM/s) than for palmolein (Vmax 2.45mM/s). Sephadex G-100 exclusion chromatography gave 24.22 fold purification with a recovery yield of 11 %. The activity of purified lipase was completely lost after storage at -20(+,ฐ) C for 69 days. Lipase catalyzed acidolysis reactions of crude palm oil with oleic acid were studied. The effect of different water activity (aw) (0.32, 0.43, and 0.84) on the reaction catalyzed by lipase from ~iPseudomonas~i sp. KLB1 (500 Unit/g(,mixture) in the ratios of crude palm oil to oleic acid (5:5, 6:4, 7:3, 8:2, and 9:1 mol:mol) were compared at 45(+,ฐ)C, 300 rpm for 75 hr. The ratio 5:5 (mol:mol) showed the highest increase of the Iodine Index value from 46.29 to 67.37 and decrease of the slip melting point was 10-15(+,ฐ)C in the modified oil from the reaction performed. under conditions controlled at 0.32 of a(,W) 300 rpm of shaking rate and at 50(+,ฐ)C. The oleic acid content in the modified oil was increased by 35% whereas the palmitic acid content was decreased by 47%. In the present study, the lipase of Pseudomonas sp. KLB1 was able to reduce the slip melting point of crude palm oil about 10-15(+,ฐ)C. Therefore, it is possible to apply this type of lipase to the palm oil industry in order to decrease consistency but increase fluidity of crude palm oil in the transferring system of the storage and refining process. The oleic acid conversion rate was also studied. The conversion rate of oleic acid in the modified oil (5:5 mol:mol) at 25 hr was 13.06 mg/g.hr, and the conversion was raised to the highest oleic acid content of 378.47 mg/g by 51 hr. The results show the desired acyl synthesis activity of this lipase. Three techniques (adsorption, covalent adsorption coupled with glutaraldehyde on rice husk ash, and entrapment in sol-gel of rice husk ash) were applied for immobilization of lipase from ~iPseudomonas~i sp. KLB1. The enzyme was strongly immobilized by entrapment in neutral sol-gel of rice husk ash. It was optimally active at 50(+,ฐ) C and pH 9. Its activity was constant in the medium pH 9 at 70(+,ฐ)C for 1 hr. The immobilized lipase was activated by Ca('2+), K('+), Na('+), EDTA and ascorbic acid but inhibited by Fe 2% Mn('2+), Co('2+), and KI. The Ca ('2+) and Na('+) were mainly found in rice husk ash and also xerogel. The most effective concentration of CaCl(,2) for enzyme activation was 20 mM. Regarding reuseability, the enzyme could be applied to hydrolysis of p-nitrophenyl palmitate (pNPP) and acidolysis of crude palm oil 12 and 5 times, respectively: The activity of entrapped lipase was completely lost after being stored at -20(+,ฐ)C for 96 days. The Km and Vmax of pNPP hydrolysis catalyzed by the entrapped enzyme were 7.43 x 10('-2) mM, and 1.94 x 10('-5) mM/s, respectively, while those of the free enzyme were 21.69 mM, and 3.90 x 10('-3) mM/s, respectively. The mechanism of the reaction of crude palm oil with oleic acid catalyzed by the lipase from ~iPseudomonas~i sp. KLB1 entrapped in sot-gel of rice husk ash was investigated under optimized conditions. The reactions revealed the catalysis mechanism of the immobilized lipase to be Ping Pong Bi Bi model. The values for Ki, Vmax, K(,crude palm oil) of this reaction were 0.0856, 2.914 mg/g.hr, 3.86 x 10('-4)mg/g, and 1.189 mg/g, respectively.