Stabilization of water‐in‐oil emulsions using a wax ester synthesized by a new homemade heterogeneous biocatalyst

BACKGROUND Cetyl palmitate is a wax ester naturally found in sperm whale spermaceti, and it is of importance in the cosmetics industry. International regulations prohibit the sale of sperm whale spermaceti, so it is now being replaced by pure cetyl palmitate obtained by a chemical route or from mixtures based on jojoba oil. Another alternative is to use an enzymatic route for wax ester synthesis. For such a purpose, a new heterogeneous biocatalyst was prepared by our research group via physical adsorption of Burkholderia cepacia lipase on aerogel modified with a protic ionic liquid (IB-IL-OPT). Its catalytic activity was compared with that of a biocatalyst prepared using a non-chemically modified silica aerogel (IB-Control). The objective of this work was to apply this homemade heterogeneous biocatalyst to cetyl palmitate synthesis via a direct esterification reaction in a solvent system and to test the final product as a stabilizing agent in water-in-oil emulsions. RESULTS IB-IL-OPT achieved maximum acid conversion of 95-100% under optimal experimental conditions established using a central composite rotational design: biocatalyst concentration of 14.8% (w/w), molar ratio of 1:1.3, 41 degrees C for 15 h of reaction under continuous mechanical agitation (200 rpm). The IB-Control gave 58.8% acid conversion in similar conditions. IB-IL-OPT was successively reused for four cycles. The wax ester showed potential as a good emulsifier for virgin coconut oil. CONCLUSIONS The cetyl palmitate obtained via an enzymatic route without further purification showed good emulsifying potential, forming Pickering emulsions. This opens new perspectives for study and applications in the cosmetics industry. (c) 2022 Society of Chemical Industry (SCI).