Process-unit coupling and integration strategy for the novel lignocellulosic biorefinery development based on systematic self-supply and recyclable xylonic acid pretreatment

Abstract

A novel technological approach was explored to develop the green lignocellulose biorefinery with self-supply and recyclable xylonic acid (XA) pretreatment. Some key process-units were therefore designed and involved such as XA pretreatment (XAP), whole-cell catalysis (WCC) of xylose to XA, electrodialysis separation (EDSR) and recycle of XA and xylo-oligosaccharides, enzymatic hydrolysis of cellulose (EHC). In term of the contamination troubles of degraded chemicals in EDSR, the anion exchange resin was also imported into the system to improve the separation and recycle of the degraded chemicals mixture. By comparison of varied integration modes with the above process-units on basis of the coupling mechanism study, the in-situ resin adsorption was combined into WCC to form the process-unit of IRA-WCC. A systematic integration strategy for every process-unit position and coupling mode was finally suggested for lignocellulose biorefinery development. Besides the full self-supply and recycle of XA catalyst, we obtained 121.15 g of xylo-oligosaccharides, 152.62 g of additional XA and 322.4 g of enzyme-hydrolyzed glucose from 1000 g of corncob with theoretical yields of 77.01% and 95.95% of xylan conversion and glucose harvest, respectively.