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Lipase catalyzed synthesis of l-alanyl esters of carbohydrates

Paper ID Volume ID Publish Year Pages File Format Full-Text
18293 42717 2007 11 PDF Available
Title
Lipase catalyzed synthesis of l-alanyl esters of carbohydrates
Abstract

Synthesis of l-alanyl esters of carbohydrates like aldohexoses (d-glucose, d-galactose and d-mannose), ketohexose (d-fructose), pentoses (d-arabinose and d-ribose) and disaccharides (lactose, maltose and sucrose) were carried out using Rhizomucor miehei lipase (RML) in organic solvents with conversion yields in the range 8–56%. Enzymatic esterification between l-alanine and d-glucose using RML and porcine pancreas lipase (PPL) was investigated in terms of incubation period, enzyme concentration, substrate concentration, buffer salts (pH and concentration) and enzyme reusability. RML has shown a maximum conversion yield of 28% (1.12–0.88 mmol monoesters and 0.24 mmol diesters) at 1 mmol d-glucose and 4 mmol l-alanine in presence of 30% RML (w/w, d-glucose) and 0.1 mM (0.1 ml) pH 4.0 acetate buffer in 72 h. PPL showed a maximum yield of 18% (0.36–0.28 mmol monoesters and 0.08 mmol diesters) at 1 mmol d-glucose and 2 mmol l-alanine in presence of 40% lipase (w/w, d-glucose) and 0.1 mM (0.1 ml) pH 5.0 acetate buffer in 72 h. In presence of buffer salts, RML showed 22% higher ester yield than in its absence under the same experimental conditions. However, buffer salts did not enhance esterification with PPL. Two-dimensional HSQCT NMR confirmed formation of 1-O-, 2-O-, 3-O-, 4-O-, 5-O-, 6-O- and 6′-O-monoesters and 1,6-di-O-, 2,5-di-O-, 2,6-di-O-, 3,5-di-O-, 3,6-di-O-, 4,6-di-O and 6,6′-di-O-diesters to varying extents depending on the carbohydrate employed.

Keywords
l-Alanyl esters of carbohydrates; Diesters; Enzymatic esterification; Monoesters; Porcine pancreas lipase; Rhizomucor miehei lipase
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 40, Issue 2, 4 January 2007, Pages 299–309
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us