Downstream Process of Xylanase Production from Oil Palm Empty Fruit Bunches: A Review

Abstract As an enzyme that can hydrolyze the glycosidic bond of hemicellulose, xylanase is widely used in pulp and paper, feed, food, and beverage industries. The vast availability of lignocellulosic biomass waste offers the potential of xylanase production by microorganisms via submerged and solid-state fermentation. However, the specific activity of the produced crude enzyme is still too low to be directly used in a commercial application. Downstream processing of the enzyme, that is purification and concentration, is necessary. Centrifugation or filtration can be used as a pre-treatment process for biomass separation before the next purification technologies. Precipitation, aqueous two-phase system (ATPS), chromatography, and membrane ultrafiltration (UF) are technologies for enzyme purification. Freeze drying can be used also as a late-stage purification procedure. ATPS and membrane UF have been emerged as a recovery method enabling the purification and concentration of the target biomolecule in a single operation. The downstream process of an enzyme usually accounts for 70-90% of the total production cost. Nonetheless set of purification methods that have high purification factors, cost-effective, high productivity, and environmentally benign strategies are needed such that the xylanase production process can be conducted economically at an industrial/commercial scale. This paper reviews processes for xylanase purification/concentration produced by using solid-state fermentation configuration. A membrane-based process for downstream processing of xylanase production is suggested.