3D Pringting Combined With Near-field Electrospinning Immobilized Xylanase

Due to its high specific surface area and adjustable porosity,electrospun fiber materials can be used as carriers for enzyme immobilization,improving reusability and reducing costs.In this paper,a fiber membrane with good performance was prepared by 3D printing combined with near-field electrospinning technology for the immobilization of xylanase,thereby improving the storage and operation stability of the enzyme.First,the electrospinning machine was modified to optimize the spinning parameters and determine the 3D pattern.Polyvinyl alcohol(PVA)and chitosan(Cs)were selected as electrospinning materials.According to the results of rheology and other characterizations,the most suitable material was selected.The optimal ratio was finally determined as the spinning voltage of 5k V and the spinning distance of 10 mm and the push speed is 0.001 mm/s.The electrospinning solution was spun to prepare a microfiber membrane,and glutaraldehyde vapor was used for cross-linking.The cross-linked fiber membrane was characterized,including mechanical property tests,water resistance and thermal stability tests,which proved that the fiber membrane has excellent performance of immobilized carriers.Then,the xylanase was immobilized by blending with the electrospinning solution,and the immobilization efficiency of the enzyme was calculated to be60% based on the theoretical loading and elution amount.X-ray diffractometer(XRD)and confocal laser microscopy were used,which proved that the xylanase was uniformly dispersed on the fiber membrane;the degradation products of xylan were analyzed by liquid chromatography-mass spectrometry(HPLC-MS),and it was proved that the products contained xylose and xybiose.The optimal reaction conditions of free enzyme and immobilized enzyme,including temperature and p H,were explored.In the batch experiment,after the immobilized xylanase was reused 7 times,the immobilized enzyme could still reach more than 75% of the initial enzyme activity,with good reuse rate;and after the immobilized enzyme was stored in the buffer solution for 28 days It still has 96% of the initial vitality and has good storage stability.Finally,the corn stalks were pretreated,and the structural changes of the pretreated corn stalks were analyzed by SEM,AFM,XRD,etc.The factors affecting the rate of enzymatic hydrolysis of corn stover include reaction time,temperature,p H and so on.In summary,this paper uses chitosan and polyvinyl alcohol to prepare fiber membrane-immobilized xylanase by 3D printing combined with near-field electrospinning,which greatly improves the reusability and storage stability of the enzyme.This method has obvious advantages in application prospects.