Synthesis of lauroyl saccharides through lipase-catalyzed condensation in microaqueous water-miscible solvents

Monoacylation of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid by protease in N,N-dimethylformamide with low water content

2-O-alpha-D-Glucopyranosyl-L-ascorbic acid (AA-2G) laurate was synthesized from AA-2G and vinyl laurate with a protease from Bacillus subtilis in N,N-dimethylformamide (DMF) with low water content. Addition of water to DMF dramatically enhanced monoacyl AA-2G synthesis. Maximum synthetic activity was observed when 3% (v/v) water was added to the reaction medium. Under the optimal reaction conditions, 5-O-dodecanoyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acid, 2-O-(6'-O-dodecanoyl-alpha-D-glucopyranosyl)-L-ascorbic acid, and 6-O-dodecanoyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acid were synthesized in yields of 5.5%, 3.2%, and 20.4%, respectively.

Microbial lipases: at the interface of aqueous and non-aqueous media. A review

In recent times, biotechnological applications of microbial lipases in synthesis of many organic molecules have rapidly increased in non-aqueous media. Microbial lipases are the 'working horses' in biocatalysis and have been extensively studied when their exceptionally high stability in non-aqueous media has been discovered. Stability of lipases in organic solvents makes them commercially feasibile in the enzymatic esterification reactions. Their stability is affected by temperature, reaction medium, water concentration and by the biocatalyst's preparation. An optimization process for ester synthesis from pilot scale to industrial scale in the reaction medium is discussed. The water released during the esterification process can be controlled over a wide range and has a profound effect on the activity of the lipases. Approaches to lipase catalysis like protein engineering, directed evolution and metagenome approach were studied. This review reports the recent development in the field ofnon-aqueous microbial lipase catalysis and factors controlling the esterification/transesterification processes in organic media.

Equilibrium Yields of Mono- and Di-lauroyl Mannoses Through Lipase-catalyzed Condensation in Acetone in the Presence of Molecular Sieves

Modification was made to our previously reported method to predict the equilibrium yields for the synthesis of mono- and di-lauroyl mannoses through the lipase-catalyzed condensation of lauric acid and mannose in acetone in the presence of molecular sieves. HPLC and mass spectra (MS) analyses indicated that two types of dilauroyl mannoses, which would be positional isomers of each other and are designated dilauroyl mannose I and II, were produced as well as monolauroyl mannose. The predicted yields of total mannose esters and dilauroyl mannose I agreed well with the experimental ones on the whole. The equilibrium yields of dilauroyl mannose II were higher than the predicted values, while the experimental values of monolauroyl mannose were lower than the predicted values.

Synthesis of esters by immobilized-lipase-catalyzed condensation reaction of sugars and fatty acids in water-miscible organic solvent

A lipase-catalyzed condensation reaction in an organic solvent is a promising means of synthesizing esters. Reaction equilibrium constant, which is usually defined on the basis of reactant concentration, is an important parameter for estimating equilibrium yield. It is shown that the constant is markedly, affected by some factors, such as the hydration of a sugar substrate and the interaction of a reactant with a solvent. To reasonably design the reaction system or determine the reaction conditions, attention should be paid to these factors. From the viewpoint of kinetics, substrate selectivity for carboxylic acids also numerically correlates to the electrical and steric properties of these acids. Reactor systems for continuously producing esters through an immobilized-lipase-catalyzed condensation reaction are developed.