การพัฒนาเซลลูโลสติดแม่เหล็กจากเปลือกสับปะรดสำหรับตรึงเอนไซม์เพื่อเพิ่มสเถียรภาพของเอนไซม์และการนำกลับมาใช้ใหม่

Xylanases as one of the important industrial enzymes, are currently receiving much attention due to their widespread applications in the food, and beverage industries, feedstock improvement, wastewater treatment and bioconversion of lignocelluloses waste to useful productions. However, the practical industrial applications of these important enzymes in many fields are often limited by high sensitivity to the environmental conditions, their short lifetime, and low operational stability as well as the difficulty of recovering from the reaction medium for subsequent reuse have hindered the application of free cellulases on industrial scale. To overcome the drawbacks, immobilization of xylanase on various natural and synthetic supports is considered to be an impressive and effective strategy to improve the stability of enzyme and its easy separation from the reaction systems and recycling for reuse. Compared with free enzyme, the immobilized enzyme exhibited significantly enhanced stability and solvent tolerance, due to the increase of enzyme structure rigidity. Moreover, the observable optimum pH and temperature of immobilized enzyme were higher than those of free enzyme (Cao et al., 2019). Accordingly, the development of novel and convenient methods for immobilization of xylanase is still critically needed.

Magnetic nanoparticles are suitable nanocarriers to separate enzymes from the reaction mixture by using an external magnet while being efficient by reducing recycling costs. It offers a method to produce renewable biomaterial without competing with food production as cellulosic materials are often byproducts in agricultural processe. Thailand annually produces 2.36 tons of pineapple (Office of Agricultural Economics 2018) and exports 41.3% of canned pineapple worldwide (Nation of Food Institute, Ministry of Industry 2014). Tons of pineapple peel are unavoidably generated and discarded as agricultural waste. Generally, pineapple peel are rich in cellulose, a major polysaccharide component in plant cell wall. Moreover, cellulose is low cost and environment-friendly given its non-toxicity and biodegradability.

In order to provide a greener chemistry, in-house xylanase (Xyn10D), containing cellulose-binding domain family 3which is a plant-cell wall degrading enzyme derived from Paenibacillus curdlanolyticus B6 will immobilize on magnetic nanoparticles, which allow for simple magnetic separation and recovery. The nanoparticles will characterize thoroughly and the binding parameters of cellulase on the magnetic iron oxides will investigate. Reusability and influence of the storage time will also examined. The stability of the enzyme increase by immobilization to the particles will compare to free xylanase.

This study aims to develop novel non-covalent immobilization of xylanase via carbohydrate-binding protein onto the pineapple cellulose magnetic nanoparticles and generate a stabilized xylanase with improved catalytic activity and stability. The magnetic nanoparticles exhibit excellent recovery properties as carrier materials in enzyme catalysis andpaves the way for industrial applications.