Investigation of xylanase properties and possibilities of immobilization using sodium alginate
Recently, attention has been paid to the processing of byproducts of agriculture into valuable components, and the use of immobilized enzymes for this purpose has become more and more interesting due to the possibility to increase their stability, as well as economic benefit. The aim of this work was to select xylanase producing fungi and to evaluate the influence of temperature and media pH on the activity of enzyme, as well as to evaluate the possibility of xylanase immobilization: (i) covalently on a solid carrier and (ii) encapsulating in alginate gel. In this study ten microscopic fungi were screened for xylanase activity and one belonging to Penicillium sp. genus was selected for further experiments as it produced the highest amount of xylanases. The optimum temperature for xylanases production by Penicillium sp. was 70–100°C and pH 6. Xylanases produced by Penicillium sp. were immobilised: (i) covalently on glutaraldehyde activated alginate beads and (ii) in sodium alginate gel beads. The covalent immobilization efficiency was optimized by changing the immobilization conditions: glutaraldehyde concentration, enzyme load and coupling time. The immobilization yield of covalent immobilization and the immobilization in sodium alginate beads were 91 and 65%, respectively.