Development of a Sustainable Biocatalytic Process for Geranyl Benzoate Production Using Immobilized Lipase

The demand for sustainable and natural alternatives in the flavor and fragrance industries has driven interest toward enzymatic synthetic routes. This study reports the enzymatic production of geranyl benzoate, a monoterpenoid ester with potential bioactivity and commercial applications, catalyzed by immobilized lipases using a solvent-free system. A central composite design was employed to optimize the key process variables: molar ratio, temperature, and enzyme loading using Lipozyme 435 as the biocatalyst. Under optimal conditions (1:7 molar ratio, 80°C, 30% enzyme), a high geraniol conversion (72%) was achieved within 6 hr, as validated by a predictive model. The study also investigated the inhibitory effects of coproduced methanol, demonstrating that open-reactor systems (enabling methanol evaporation) enhanced conversion (>99% in 48 h) compared to closed systems. Additionally, substrate-exposure experiments highlighted methyl benzoate's inhibitory effect on Lipozyme 435, reducing its activity by 54%, whereas Lipura Flex showed greater resilience. Reusability tests indicated a decline in enzyme performance, with Lipozyme 435 retaining 22% activity after five cycles. Cell tests demonstrated no cytotoxicity and proliferative effect at high concentrations. These findings highlight the potential of solvent-free enzymatic processes for sustainable production of geranyl benzoate and provide insights into operational challenges, including methanol management and biocatalyst stability.