The green novel approach in hydrolysis of pistachio shell into xylose by microwave‐assisted high‐pressure <scp>CO<sub>2</sub></scp>/<scp>H<sub>2</sub>O</scp>
Filiz Hazal, Hatice Neval Özbek, Fahrettin Göğüş, Derya Koçak Yanık
Abstract
Abstract BACKGROUND Pistachio shell is a valuable lignocellulosic biomass because almost 90% of its hemicellulose fraction is xylan, which can be converted into high value‐added compounds such as xylooligosaccarides, xylose, xylitol and furfural. The present study represents a green and novel approach to produce xylose from lignocellulosic biomass. Microwave‐assisted high‐pressure CO 2 /H 2 O hydrolysis (MW‐HPCO 2 ) comprising a combination never previously used was performed to produce xylose from pistachio shell. RESULTS Response surface methodology with a Box–Behnken design was implemented to optimize microwave‐assisted high‐pressure CO 2 /H 2 O hydrolysis (MW‐HPCO 2 ). The effect of temperature, time and liquid‐to‐solid ratio was studied in the ranges of 180–210 °C, 10–30 min and 5–30 mL g −1 , respectively. A maximum xylose yield of 61.39% and minimum degradation compounds (5‐hydroxymethyl furfural and furfural) of 11.07% were attained under reaction conditions of 190 °C, 30 min and 18 mL g −1 . CONCLUSION The results showed that hydrolysis temperature, time and liquid‐to‐solid ratio had a strong influence on the xylose yield, as well as on the formation of degradation compounds. MW‐HPCO 2 significantly increased accessibility to cellulose‐derived products in the subsequent enzymatic hydrolysis. The results of the present study reveal that MW‐HPCO 2 can be a promising green technique for the hydrolysis of lignocellulosic biomass. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.