Intensification of Enzymatic Synthesis of Decyl Oleate Using Ultrasound in Solvent Free System: Kinetic, Thermodynamic and Physicochemical Study

Hemp tea waste-immobilized lipase for the synthesis of alkyl oleates in solvent free systems

This study explores the immobilization of lipase from Candida rugosa (CRL) on hemp tea waste to catalyze the esterification of oleic acid with primary aliphatic C2-C12 alcohols in a solvent-free system. The immobilization method employed was adsorption, chosen for its simplicity, low cost, and ability to preserve enzyme activity. The esterification of undecanoic acid, lauric acid, and oleic acid with alcohols of varying chain lengths (ethanol, 1-propanol, 1-butanol, 1-octanol, 1-decanol, and 1-dodecanol) was studied. The esterification efficiency was found to be influenced by the type of alcohol, the molar ratio of oleic acid to alcohol, and the water content in the reaction medium. The highest conversions were achieved with ethanol (23 % conversion with 18.5 % water and a molar ratio of 1:5) and 1-decanol (30 % conversion with no added water and a molar ratio of 1:2). Comparatively, the soluble lipase achieved slightly higher conversion of oleic acid using decanol (38 %), indicating that the performance may be attributed to origin of lipase, rather than the immobilization procedure. The study demonstrated that the immobilization of lipase on hemp tea waste did not hinder enzyme activity. Additionally, the biocatalyst developed can function in a completely solvent-free system, offering a green solution by repurposing waste materials for industrial ester production.

Esters in the Food and Cosmetic Industries: An Overview of the Reactors Used in Their Biocatalytic Synthesis

Esters are versatile compounds with a wide range of applications in various industries due to their unique properties and pleasant aromas. Conventionally, the manufacture of these compounds has relied on the chemical route. Nevertheless, this technique employs high temperatures and inorganic catalysts, resulting in undesired additional steps to purify the final product by removing solvent residues, which decreases environmental sustainability and energy efficiency. In accordance with the principles of "Green Chemistry" and the search for more environmentally friendly methods, a new alternative, the enzymatic route, has been introduced. This technique uses low temperatures and does not require the use of solvents, resulting in more environmentally friendly final products. Despite the large number of studies published on the biocatalytic synthesis of esters, little attention has been paid to the reactors used for it. Therefore, it is convenient to gather the scattered information regarding the type of reactor employed in these synthesis reactions, considering the industrial field in which the process is carried out. A comparison between the performance of the different reactor configurations will allow us to draw the appropriate conclusions regarding their suitability for each specific industrial application. This review addresses, for the first time, the above aspects, which will undoubtedly help with the correct industrial implementation of these processes.