Influence of buffer and L-phenylalanine concentration in the Rhizomucor miehei lipase catalysed synthesis of L-phenylalanyl-D-glucose ester investigated through response surface methodology.

Kenchaiah, Lohith and Balaraman, Manohar and Soundar, Divakar (2006) Influence of buffer and L-phenylalanine concentration in the Rhizomucor miehei lipase catalysed synthesis of L-phenylalanyl-D-glucose ester investigated through response surface methodology. European Food Research and Technology, 224 (2). 219-224 ; 22 ref..

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Abstract

Reaction conditions for Rhizomucor miehei lipase (RML) catalysed synthesis of L-phenylalanyl-D-glucose using unprotected L-phenylalanine and D-glucose were optimized using response surface methodology (RSM). A central composite rotatable design (CCRD) was employed involving 32 experiments with 5 variables (L-phenylalanine concn. in mmol, amount of RML in mg, pH, incubation period in h and buffer concn. in mM) at 5 levels. A second-order polynomial equation was developed in terms of linear, quadratic and cross product terms to study the effects of variables on esterification yields. An R2 value of 0.7 was obtained for this complex reaction. Surface and contour plots revealed that higher yields occurred within a very narrow pH range of 4.5-6.5 at L-phenylalanine concn. >3 mmol. Extent of esterification decreased with increases in RML concn. for incubation periods <60 h. However, longer incubation periods >60 h, enhanced esterification at all RML concn. Lower conversions <0.5 mmol required <3.5 mmol L-phenylalanine concn. and a broad range of buffer concn. from 0.1mM (0.1 ml, 0.1M buffer of pH 6.0) to 0.5mM (0.5 ml, 0.1M buffer of pH 6.0). However, higher conversions from 0.6 to 0.8 mmol required a buffer concn. >0.25mM (0.25 ml, 0.1M buffer of pH 6.0) at L-phenylalanine concn. >3.5 mmol. An optimum predicted yield of 1.01 mmol for L-phenylalanyl-D-glucose at 3 mmol L-phenylalanine, 100 mg of RML, 24 h incubation period, 0.5mM (0.5 ml of 0.1M buffer), pH 4.8 acetate buffer resulted in a product concn. of 0.97 mmol. Validation experiments carried out under random conditions also exhibited good correspondence between predicted and experimental yields.

Item Type:	Article
Uncontrolled Keywords:	AMINO-ACIDS; ESTERIFICATION-; GLUCOSE-; LIPASES-; RHIZOMUCOR-; PHENYLALANINE-; RHIZOMUCOR-MIEHEI
Subjects:	500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 15 Cellulose Chemistry
Divisions:	Fermentation Technology and Bioengineering Food Engineering
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	09 Aug 2008 10:04
Last Modified:	28 Dec 2011 10:02
URI:	http://ir.cftri.res.in/id/eprint/8090

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