Equilibrium constant for lipase-catalyzed condensation of mannose and lauric acid in water-miscible organic solvents

Renewable, sustainable, and natural lignocellulosic carriers for lipase immobilization: A review

It is well-known that enzymes are molecules particularly susceptible to pH and temperature variations. Immobilization techniques may overcome this weakness besides improving the reusability of the biocatalysts. Given the strong push toward a circular economy, the use of natural lignocellulosic wastes as supports for enzyme immobilization has been increasingly attractive in recent years. This fact is mainly due to their high availability, low costs, and the possibility of reducing the environmental impact that can occur when they are improperly stored. In addition, they have physical and chemical characteristics suitable for enzyme immobilization (large surface area, high rigidity, porosity, reactive functional groups, etc.). This review aims to guide readers and provide them with the tools necessary to select the most suitable methodology for lipase immobilization on lignocellulosic wastes. The importance and the characteristics of an increasingly interesting enzyme, such as lipase, and the advantages and disadvantages of the different immobilization methods will be discussed. The various kinds of lignocellulosic wastes and the processing required to make them suitable as carriers will be also reported.

Sugar ester surfactants: enzymatic synthesis and applications in food industry

Sugar esters are non-ionic surfactants that can be synthesized in a single enzymatic reaction step using lipases. The stability and efficiency of lipases under unusual conditions and using non-conventional media can be significantly improved through immobilization and protein engineering. Also, the development of de novo enzymes has seen a significant increase lately under the scope of the new field of synthetic biology. Depending on the esterification degree and the nature of fatty acid and/or sugar, a range of sugar esters can be synthesized. Due to their surface activity and emulsifying capacity, sugar esters are promising for applications in food industry.

Medium-engineering: a useful tool for modulating lipase activity and selectivity

The design of a specific reaction medium capable to enhance activity, stability, and productivity of biocatalysts has been a recurring topic of study during the last three decades. The remarkable properties and valuable applications of enzymes, especially lipases, have inspiried different strategies for improving their performance in near-anhydrous media. As lipases are the most frequently used enzymes in organic synthesis, understanding the influence of reaction media on their activity and selectivity is crucial. In this paper, we review the key features of lipases and demonstrate how medium-engineering is a useful tool to modulate the activity and selectivity of lipase-catalyzed reactions.

Thermodynamical methods for the optimization of lipase-catalyzed reactions

A basic insight on different thermodynamical strategies reported for the optimization of lipase-catalyzed reactions is presented. The significance of selecting the appropriate reaction media in order to enhance selectivity and operational stability of enzymes is discussed. From this analysis, the importance of developing thermodynamic strategies for controlling both the reaction kinetics and equilibrium is emphasized. A theoretical model (Conductor-like Screening Model for Realistic Solvation) for calculating thermodynamic properties in fluid phases is proposed as a powerful tool for predicting equilibrium and kinetic behavior in biocatalytic processes.

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.