Immobilization of Candida Rugosa Lipase on Zea Mays L. husk leaf activated carbon for hydrolysis and esterification reaction

Abstract

Poor management of the generated waste from the by-products from agricultural land and commercial food industries have contributed to increased ecological burden. The potential of waste biomass in current agriculture practice is not fully utilize the biomass, and left to decompose in field or are burned. Therefore, development of technologies that fully utilize these wastes is, therefore, necessary. In this study, Zea mays L. husk leaves (ZHL) were chemically activate using phosphoric acid (H3PO4) under activation temperature of 500°C to obtain ZHL activated carbon (ZHLAC). In order to enhance the immobilization of enzyme by covalent bonding, surface functionalized ZHLAC were prepared using ethylendiamine and glutaraldehyde to increase the functional group on support surface. The biocatalyst study of CRL-FZHLAC using FTIR, TGA and Nitrogen Adsorption revealed CRL were successfully bound to the surface of the FZHLAC support via imine bond formed through a Schiff base mechanism. Thermogravimetric analysis revealed that CRL-FZHLAC was successful prepared with an enzyme loading of 12 % (v/v). The effectiveness of CRL-FZHLAC in enzymatic reaction by hydrolysis of olive oil was performed and optimized under various conditions of temperature, pH of solvent buffer, stirring rate and reusability. Subsequently, enzymatic synthesis of butyl butyrate was also optimized under various conditions of temperature, molar ratio acid/alcohol and stirring rate. Maximum activity of CRL-FZHLAC for hydrolysis (71.24 µmol/min/g) was achieved under an optimized condition of 3 h, 50°C, 200 rpm at pH 8. Under optimum condition [3 h, 40°C, molar ratio of acid/alcohol of 1:2 and 200 rpm], the lipase successfully synthesize 87% of butyl butyrate as compare to 62.9% by the free CRL [3 h, 40oC, molar ratio of acid/alcohol of 1:2 and 200 rpm]. CRL-FZHLAC was reusable for up to 5 cycles the hydrolysis of olive oil and 7 cycles the synthesis of butyl butyrate. In short, it was concluded that AC obtained from waste ZHL was suitable as a raw material to prepare a highly functional FZHLAC. Activity of CRL-FZHLAC was improved to produce high yield of both synthesis of olive oil and butyl butyrate. Thus, the development CRL-FZHLAC was a possible practice in increasing the efficiency of hydrolysis and esterification reaction.