Abstract
Candida antarctica lipase B (CalB) enzyme was encapsulated and cross-linked by silica matrix to enhance its thermal stability and reusability, and demonstrated an enzymatic ability for rapid hydrolysis and esterification. Silica encapsulated CalB particles (Si-E-CPs) and silica cross-linked CalB particles (Si-CL-CPs) were prepared as a function of TEOS concentration. The particle size analysis, thermal stability, catalytic activity in different pHs, and reusability of Si-E-CPs and Si-CL-CPs were demonstrated. Furthermore, the determination of the CalB enzyme in Si-E-CPs and Si-CL-CPs was achieved by Bradford assay and TGA analysis. Enzymatic hydrolysis was performed against the p-nitrophenyl butyrate and the catalytic parameters (Km, Vmax, and Kcat) were calculated by the Michaelis–Menten equation and a Lineweaver–Burk plot. Moreover, enzymatic synthesis for benzyl benzoate was demonstrated by esterification with an acyl donor of benzoic acid and two acyl donors of benzoic anhydride. Although the conversion efficiency of Si-CL-CPs was not much higher than that of native CalB, it has an efficiency of 91% compared to native CalB and is expected to be very useful because it has high thermal and pH stability and excellent reusability.
Highlights
The active site of Candida antarctica lipase B (CalB) is not covered by a lid and, the active site for the hydrophobic substrate is directly accessible to the solvent [15]
The catalytic activities of native CalB, Si-E-CPs, and Si-CLCPs were investigated with hydrolysis of p-NPB, in the temperature range of 25–65 ◦C to access the thermal stability of the enzyme
These results indicate that benzoic anhydride is suitable for benzyl benzoate synthesis
Summary
Lipases have been used in various industries, such as agriculture, medicine, pharmaceuticals, and cosmetics, due to their high activity and regioselectivity [1–5]. Lipases generally catalyze a hydrolysis reaction, but they effectively perform synthesis reactions (esterification, acylation, etc.) in a non-aqueous or low-water environment [9,10]. It is difficult to maintain the structural stability of proteins during biochemical reactions, which may affect the biological activity of lipase [18,19]. Gener2aolfly, lipases are sensitive to process conditions other than the optimal conditions, normally a narrow pH range, and low thermal stability [15]. We synthesized benzyl benzoate, an aromatic ester, by esterification and acylation using two acyl donors, benzoic anhydride and benzoic acid with native CalB and. We synthesized benzyl benzoate, an aromatic ester, by esterification and acylation using two acyl donors, benzoic anhydride and benzoic acid with nativ3eofC1a3lB and Si-CL-CPs. The synthetic efficiency for benzyl benzoate with native CalB and Si-CLCPs was calculated and an available mechanism is suggested. The synthetic efficiency for benzyl benzoate with native CalB and Si-CL-CPs wa2s. cRaelscuullatsteadnadnDdiasncuasvsaioilnable mechanism is suggested
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