Strategy for production of high-purity rare sugar D-allulose from corn stover

Here, we report a strategy for producing high-value and high-purity rare sugar D-allulose from inexpensive corn stover. To eliminate the negative impact of xylan hydrolysis products on the production of D-allulose, NH4Cl treatment was employed to thoroughly remove xylan from corn stover. By using 0.6 M NH4Cl to treat the corn stover at 160 °C for 1 h, 97.2% of xylan was removed. After the pretreatment, 92% of cellulose in the corn stover was degraded into glucose by CTec2 and 17.9% (close to the theoretical conversion rate) of glucose was further transformed into D-allulose by D-Tagatose 3-epimerase and D-glucose isomerase. After separation and purification through MCK-35 calcium ion resin, followed by freeze-drying, the obtained solid D-allulose had a purity of 99.4%. This study establishes a low-cost and affordable source for D-allulose production, while simultaneously presenting a new direction for enhancing the high-value utilization of lignocellulosic biomass.