Characterization of Carboxylic Acid Reductase from Mycobacterium phlei Immobilized onto Seplite LX120
Rose Syuhada Basri, Raja Noor Zaliha Raja Abd Rahman, Nor Hafizah Ahmad Kamarudin, Wahhida Latip, Mohd Shukuri Mohamad Ali
Abstract
A multi-domain oxidoreductase, carboxylic acid reductase (CAR), can catalyze the one-step reduction of carboxylic acid to aldehyde. This study aimed to immobilize bacterial CAR from a moderate thermophile Mycobacterium phlei (MpCAR). It was the first work reported on immobilizing bacterial CAR onto a polymeric support, Seplite LX120, via simple adsorption. Immobilization time and protein load were optimized for MpCAR immobilization. The immobilized MpCAR showed optimal activity at 60 °C and pH 9. It was stable over a wide range of temperatures (10 to 100 °C) and pHs (4–11), retaining more than 50% of its activity. The immobilized MpCAR also showed stability in polar solvents. The adsorption of MpCAR onto the support was confirmed by Scanning Electron Microscopy (SEM), Fourier-Transform Infrared (FTIR) spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. The immobilized MpCAR could be stored for up to 6 weeks at 4 °C and 3 weeks at 25 °C. Immobilized MpCAR showed great operational stability, as 59.68% of its activity was preserved after 10 assay cycles. The immobilized MpCAR could also convert approximately 2.6 mM of benzoic acid to benzaldehyde at 60 °C. The successfully immobilized MpCAR on Seplite LX120 exhibited improved properties that benefit green industrial processes.