Enzymatic esterification of eugenol and benzoic acid by a novel chitosan-chitin nanowhiskers supported Rhizomucor miehei lipase: Process optimization and kinetic assessments

Publication date: Available online 12 September 2017 Source:Enzyme and Microbial Technology Author(s): Fatin Myra Abd Manan, Nursyafreena Attan, Zainoha Zakaria, Aemi S. Abdul Keyon, Roswanira Abdul Wahab A biotechnological route via enzymatic esterification was proposed as an alternative way to synthesize the problematic anti-oxidant eugenyl benzoate. The new method overcomes the well-known drawbacks of the chemical route in favor of a more sustainable reaction process. The present work reports a Box-Behnken design (BBD) optimization process to synthesize eugenyl benzoate by esterification of eugenol and benzoic acid catalyzed by the chitosan-chitin nanowhiskers supported Rhizomucor miehei lipase (RML-CS/CNWs). Effects of four reaction parameters: reaction time, temperature, substrate molar ratio of eugenol: benzoic acid and enzyme loading were assessed. Under optimum conditions, a maximum conversion yield as high as 66% at 50°C in 5h using 3mg/mL of RML-CS/CNWs, and a substrate molar ratio (eugenol: benzoic acid) of 3:1. Kinetic assessments revealed the RML-CS/CNWs catalyzed the reaction via a ping-pong bi-bi mechanism with eugenol inhibition, characterized by a Vmax of 3.83mMmin−1. The Michaelis–Menten constants for benzoic acid (K m ,A ) and eugenol (K m ,B ) were 34.04 and 138.28mM, respectively. The inhibition constant for eugenol (K i ,B) was 438.6mM while the turnover number (kcat) for the RML-CS/CNWs-catalyzed esterification reaction was 40.39min−1. RML...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research