Process design and techno-economic assessment for octyl caprylate synthesis using immobilized lipase

Octyl caprylate is an important emollient ester that can be synthesized by biocatalysis in a solvent-free system. The lack of techno-economic assessment studies in biocatalytic processes impairs the adoption of biocatalysts to produce commodities/specialties chemicals considering the high cost of immobilized biocatalysts. In this study, we evaluated reaction conditions – molar ratio of reagents, biocatalyst loading, temperature – that lead to high reagents conversions and favourable metrics – product concentration, space-time yield, and catalytic productivity – for a process development. We obtained near complete conversion of caprylic acid into octyl caprylate (99%) in short reaction time (3 h) using Lipozyme RM IM (lipase from Rhizomucor miehei immobilized onto ion-exchange resin) at 1.8% wt/wt loading and stoichiometric excess (30%) of n-octanol. The biocatalyst can be reused 20 times without significant loss in initial conversion, resulting in total catalytic productivity of 880.0 g ester g−1 biocatalyst. The process design based on lab data indicated a simplified process in which only one distillation step is enough to separate the n-octanol stoichiometric excess from the octyl caprylate post-reaction. In small industrial scale context (6000 ton product yr−1) and low capital expenditure (CAPEX), it is possible to obtain positive net present value (NPV) and potential economic feasibility in octyl caprylate enzymatic production using Lipozyme RM IM.