Xylose Release From Sunflower Stalk by Coupling Autohydrolysis and Enzymatic Post-Hydrolysis

The purpose of this study was to obtain xylose-based fermentation media from autohydrolysis liquors of sunflower stalk by using commercial xylanase formulation. Xylose is generally produced from xylan by diluted acid hydrolysis that causes the formation of some unwanted compounds during the process. As an alternative to dilute acid hydrolysis method, enzymatic hydrolysis of xylan can provide more specific hydrolysis under moderate conditions and does not cause the formation of undesirable compounds. In this study, xylose production carried out with Trichoderma longibrachiatum xylanase on solubilized xylan form of sunflower stalk, which was hydrothermally pretreated for 1 hour at 160ºC. The effects of substrate concentration and enzyme activity were investigated for the production of xylose. To obtain a high xylose yield and selectivity, the optimization study was conducted by the response surface methodology. The optimum substrate concentration and enzyme activity were found as 60 mg ds/mL CAL and 234 U/mL, respectively. Under the optimum condition, xylose yield and selectivity were found to be 69.5% and 8.2 g/g, respectively. This study showed that xylose could be produce with a high yield without requiring a neutralization process and corrosive chemical reagent apart from water.