Optimization of the enzymatic esterification of diglycerol and lauric acid

Abstract

In recent years, a number of industrial applications for lipases in biotransformation of fatty acids and lipids have been developed. One of the main reasons for this growing interest is the reduced overall catalyst cost owing to the development of commercially available immobilized enzymes, using polymeric carriers that facilitate recovery and reuse of the catalyst. Additional benefits for industrial applications include the specificity of the enzyme and the mild processing conditions. Diglycerol resulting from the dimerization of glycerol may replace molecules such as propylene glycol as the hydrophilic moiety of surfactants. Also, diglycerol fatty acid esters are useful as biodegradable nonionic surfactants for food, cosmetics, and pharmaceuticals. In this study, the enzymatic esterification of diglycerol and lauric acid has been optimized in a solvent‐free system. The reaction was carried out in a stirred batch reactor with a vacuum pump in order to shift the equilibrium toward the products. The commercial lipase Novozym‐435 was chosen as the most suitable catalyst, and the initial acid/alcohol ratio was always 1∶1. The reaction of lauric acid and diglycerol leveled off at equilibrium conversion after approximately 1 h of reaction. Previous work indicated that only temperature and catalyst concentration had significant effects on the conversion, and a full two‐factorial design has proved effective in the study of the influence of these two variables on the process. The temperature range studied was 63–77°C, and the range of the catalyst concentration was 0.2–5.8 wt%. Both catalyst concentration and temperature were found to be significant factors in the esterification process, and their influences are positive. The effect of the interaction between temperature and catalyst concentration was small. A first‐order approach could not fit the data adequately, and a model that included quadratic effects was required. A second‐order model was developed to predict the yield of ester as a function of the variables. Analysis of residuals showed that the model predicted accurately the acid conversion over the experimental range considered. This model is useful to determine the optimal operating conditions for the industrial process.

Enabling Industrial Biocatalytic Processes by Application of Silicone‐Coated Enzyme Preparations

“…This was operated at a stirring speed of 350 rpm (to mimic the specific power input observed in large-scale STR) [23] under reaction conditions (temperature, catalyst ratio, application of vacuum for water removal) adopted from the large-scale production of myristyl myristate in a fixedbed reactor. [5,24] Each production cycle covered a reaction time of 24 hours. Within this time, the reaction was run to completion (100% conversion).…”

“…[4] Unfortunately, its applicability is currently limited to the conversion and production of compounds with low to medium viscosity and none to only slightly surface-active properties. This obviates the effective production of many cosmetic compounds, for example, when diglycerol [5] , polyglycerol or other polyols like R-butylglucoside [6] are involved. Viscosity restricts the application of NZ435 because of the maximum possible pressure drop over the length of the fixed-bed reactor, which is typically used with this enzyme preparation.…”

“…Unfortunately, its applicability is currently limited to the conversion and production of compounds with low to medium viscosity and none to only slightly surface‐active properties. This obviates the effective production of many cosmetic compounds, for example, when diglycerol5, polyglycerol or other polyols like R ‐butylglucoside6 are involved.…”

Green Synthesis of Decaglycerol Laurates by Lipase-Catalyzed Transesterification of Methyl Laurate with Decaglycerol

“…e immobilized lipases have many advantages, including easy recyclability and good reusability [9]. e enzymatic esterification of polyglycerol and fatty acids to give PGFE has been carried out using lipase [10,11]. Using diglycerol and oleic acid as starting materials, acid conversion of about 90% and monoester selectivity of >94% have been achieved as the best results [12].…”

Biomicrofluidic chemoemitter systems: towards pheromone communication

“…This proves that aft loses completely its activity after 32 hours of immobilization. In comparison, the activity of the immobilized Lipozyme IM, studied for the synthesis of esters, remained stable for more than 180 days of continuous working without change in its catalytic activity (128). The results show, that the atf has moderate operational stability after immobilization.…”