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Journal of Chemical Technology and Biotechnology, 2002
Isolation of a novel microbial lipase (EC 3.1.1.3) having specific catalytic activity for the syn... more Isolation of a novel microbial lipase (EC 3.1.1.3) having specific catalytic activity for the synthesis of optically pure 2-O-benzylglycerol-1-acetate, the building block for the preparation of many β-blockers, phospholipase A2 inhibitors and other biologically active compounds was the aim of this investigation. A Pseudomonas (strain G6), recently isolated from soil, produced an extracellular lipase. SDS–PAGE analysis showed that the lipase protein was a hexamer. The molecular weight of the sub-units of the lipase protein were 10, 19, 29, 30, 47 and 53. The catalytic activity of the lipase was exploited for the synthesis of 2-O-benzylglycerol-1-acetate from 2-O-benzylglycerol through transesterification using vinyl acetate as acylating agent. High selectivity of the lipase towards the monoacetate product was demonstrated. A 97% enantiomeric excess (ee) of S(+)-2-O-benzylglycerol-1-acetate was obtained when the reaction was carried out at room temperature with shaking. The lipase was highly active in anhydrous organic microenvironments and in non-polar organic solvents with log P values above 2.5.© 2002 Society of Chemical Industry
Enzyme and Microbial Technology, 2002
Pseudomonas pseudomallei 12Sm produced an extracellular lipase during growth on n-hexadecane as t... more Pseudomonas pseudomallei 12Sm produced an extracellular lipase during growth on n-hexadecane as the sole carbon source. Sephadex G-150 filtration and native PAGE analyses of the ammonium sulphate (60%, w/v) precipitated protein of the cell-free culture broth showed the molecular mass (M r ) of the lipase protein to be about 143 kDa. The lipase was stable at high alkaline pH and the optimum activity was at pH 10. Using a simple entrapment technique, the lipase was immobilised in a polyvinyl alcohol (PVA) membrane (PAM) and was applied in the synthesis of isoamyl acetate by transesterification reaction. The stability of the immobilised lipase in organic solvents was much higher than the native lipase, particularly in the poalrity (log P) range of 0.23-0.85. The relative activity of the PAM-immobilised lipase was significantly higher than the native or celite-immobilised lipase in the temperature range of 35-50 • C. The retention of activity of the PAM-immobilised lipase at room temperature for 3 months was 62 and 70% higher than the free and celite-immobilised lipase, respectively. The apparent Michaelis-Menten constants (K m ) for immobilised and free lipase were 555 and 178 M, respectively. The catalytic efficiency of the lipase (K cat ) did not significantly altered upon immobilisation in the PAM. Water at a concentration of 0.2% in the reaction mixture increased the activity of the immobilised lipase upto 4.3-fold and this was sustained upto the fifth reaction cycle.
Bioresource Technology, 2002
Among the various lipidic and non-lipidic substances, normal alkanes within the chain lengths of ... more Among the various lipidic and non-lipidic substances, normal alkanes within the chain lengths of C-12 to C-20 served as the best carbon substrates for the production of extracellular lipase by Pseudomonas species G6. Maximum lipase production of 25 U/ml of the culture broth was obtained by using n-hexadecane as the sole carbon substrate. The optimum pH of 8 and temperature of 34 AE 1°C
Journal of Chemical Technology and Biotechnology, 2002
Isolation of a novel microbial lipase (EC 3.1.1.3) having specific catalytic activity for the syn... more Isolation of a novel microbial lipase (EC 3.1.1.3) having specific catalytic activity for the synthesis of optically pure 2-O-benzylglycerol-1-acetate, the building block for the preparation of many β-blockers, phospholipase A2 inhibitors and other biologically active compounds was the aim of this investigation. A Pseudomonas (strain G6), recently isolated from soil, produced an extracellular lipase. SDS–PAGE analysis showed that the lipase protein was a hexamer. The molecular weight of the sub-units of the lipase protein were 10, 19, 29, 30, 47 and 53. The catalytic activity of the lipase was exploited for the synthesis of 2-O-benzylglycerol-1-acetate from 2-O-benzylglycerol through transesterification using vinyl acetate as acylating agent. High selectivity of the lipase towards the monoacetate product was demonstrated. A 97% enantiomeric excess (ee) of S(+)-2-O-benzylglycerol-1-acetate was obtained when the reaction was carried out at room temperature with shaking. The lipase was highly active in anhydrous organic microenvironments and in non-polar organic solvents with log P values above 2.5.© 2002 Society of Chemical Industry
Enzyme and Microbial Technology, 2002
Pseudomonas pseudomallei 12Sm produced an extracellular lipase during growth on n-hexadecane as t... more Pseudomonas pseudomallei 12Sm produced an extracellular lipase during growth on n-hexadecane as the sole carbon source. Sephadex G-150 filtration and native PAGE analyses of the ammonium sulphate (60%, w/v) precipitated protein of the cell-free culture broth showed the molecular mass (M r ) of the lipase protein to be about 143 kDa. The lipase was stable at high alkaline pH and the optimum activity was at pH 10. Using a simple entrapment technique, the lipase was immobilised in a polyvinyl alcohol (PVA) membrane (PAM) and was applied in the synthesis of isoamyl acetate by transesterification reaction. The stability of the immobilised lipase in organic solvents was much higher than the native lipase, particularly in the poalrity (log P) range of 0.23-0.85. The relative activity of the PAM-immobilised lipase was significantly higher than the native or celite-immobilised lipase in the temperature range of 35-50 • C. The retention of activity of the PAM-immobilised lipase at room temperature for 3 months was 62 and 70% higher than the free and celite-immobilised lipase, respectively. The apparent Michaelis-Menten constants (K m ) for immobilised and free lipase were 555 and 178 M, respectively. The catalytic efficiency of the lipase (K cat ) did not significantly altered upon immobilisation in the PAM. Water at a concentration of 0.2% in the reaction mixture increased the activity of the immobilised lipase upto 4.3-fold and this was sustained upto the fifth reaction cycle.
Bioresource Technology, 2002
Among the various lipidic and non-lipidic substances, normal alkanes within the chain lengths of ... more Among the various lipidic and non-lipidic substances, normal alkanes within the chain lengths of C-12 to C-20 served as the best carbon substrates for the production of extracellular lipase by Pseudomonas species G6. Maximum lipase production of 25 U/ml of the culture broth was obtained by using n-hexadecane as the sole carbon substrate. The optimum pH of 8 and temperature of 34 AE 1°C