Development of an industrial sustainable process for wax esters production: enzyme immobilization, process optimization, and plant simulation

Abstract

BACKGROUND: As a result of the ban on whaling, there has been a shortage of spermaceti, a natural product with applications in cosmetics and pharmaceuticals. A green and sustainable process for the biocatalytic synthesis of a wax ester mixture analogue to natural spermaceti is presented in this paper. RESULTS: Immobilization of Candida antarctica lipase B by covalent binding to Purolite® Lifetech™ ECR8285 allowed for an immobilized derivative with 124.5 mg protein/g support (69.3% protein immobilization yield) that maintains 100% of its enzymatic activity after 12 months of cold storage and presents negligible loses of activity after 9 consecutive reaction cycles. The optimization of the synthesis process in a batch reactor resulted in conditions that, at 70 °C, 350 rpm, and 1.25% w/w of biocatalyst, achieved a conversion of 97% after 1 h of reaction. The simulation of a spermaceti production plant was carried out using the process simulation software aspenONE suite v10. The plant was designed for a continuous operation during 9 h per day, with a reactor of 20.25 L of working volume and a residence time of 1 h. The production of this plant would be 173.25 kg spermaceti/day, with a product purity of 99.55%. CONCLUSION: The main novelty of this work is the design of a spermaceti production plant, using the most sustainable methodologies and resulting in a product with exceptional characteristics and minimal waste generation. Moreover, a new lipase immobilized derivative is also described. The good values of sustainability indicators point to the viability of its industrial implementation.