Enzyme, medium, and reaction engineering to design a low-cost, selective production method for mono- and dioleoylglycerols

Article abstract of DOI:10.1007/BF02517939

The selective enzymic production of mono- and diolein (MO, DO) was optimized at high yields. A comparative study of the following distinct enzymic reactions was conducted: ethyl oleate glycerolysis, triolein (TO) glycerolysis, and direct esterification. Solvent-free systems were compared with media that contained different solvents. Native, modified (with polyethylene glycol), and immobilized lipases were used. Mechanical resistance, the support effect on enzyme and glycerol dispersion and on process reproducibility, and hydrophilicity of the support were considered in the process optimization. We report the use of an immobilized lipase on an inorganic support (Celite), which has high activities in both solid-phase glycerolysis (99% reaction conversion) and esterification (100% conversion). The optimum conditions for the distinct reactions were compared by considering their selectivities, conversions, yields, and cost of the substrates. We found less costly and more selective processes in the absence of solvents for glycerolysis of triolein and direct esterification. Although glycerolysis was the most interesting process to produce diolein, esterification was better for monoolein preparation with this biocatalyst. The esterification reaction yielded 93 wt% of MO, in the absence of either TO or oleic acid (OA), at low cost because of the 100% reaction conversion. Similar costs of the substrates (10.6 and 10.1 $/g) were necessary to obtain 67 and 80 wt% of DO in esterification and glycerolysis, respectively. The glycerolysis conversion was 96%. In esterification, the product mixture was impure, with a high amount of residual OA due to the low conversion (59%). The high activity of PSL-Celite in these solid-phase reactions has an advantage over the reactions with nonimmobilized lipases due to the ease of enzyme recovery. The absence of organic solvents reduces the need for solvent removal from the reaction mixtures.