Xylanase-assisted Adsorption Process for High Purity Sugar Stream Development from Hydrolysis Liquor of Kraft-Based Dissolving Pulp Production Process

This paper proposed a novel xylanase-assisted activated carbon process to produce a high-purity sugar stream from pre-hydrolysis liquid (PHL) of the kraft-based dissolving pulp production process. The results showed that the enzymatic hydrolysis could effectively improve the lignin removal and sugar purity at pH 5 and 50 degrees C. It was observed that the cleavage of lignin-carbohydrate complex (LCC) by enzyme led to more sugar and soluble lignin production in PHL. The main mechanisms involved are the reduced pore clog due to the lignin converted from colloidal to dissolved state at higher pH, lower sugar loss obtained by the reduction of polymerization degree of poly-sugars in PHL and also the removal of the lignin disconnected from the LCC. FTIR NMR, particle size, BET, and SEM analyses confirmed that the induced soluble lignin could be adsorbed by activated carbon effectively without blocking its pores, which improved the selectivity and productivity of activated carbon for removing lignin and generating higher purity sugar stream (97.5 wt. %). Based on the promising results and simplicity of the proposed operations, the introduced process may be attractive to the industry for generating high-purity sugars at an industrial scale.