An innovative pretreatment process using a recyclable aromatic acid, p-toluenesulfonic acid (p-TsOH), was developed for lignocellulose fractionation and improvement in cellulose digestibility as well as lignin extraction in this study. Three different feedstocks including corncobs, wheat straw, and Miscanthus were pretreated by p-TsOH at a 70% (wt) concentration at 80 degrees C for 10 min for comparison. The results showed that p-TsOH pretreatment was highly effective in removing lignin and xylan, and it resulted in the production of cellulose-rich water-insoluble solids (WIS) and spent liquor, primarily containing xylose and lignin. The produced WIS from corncobs, wheat straw, and Miscanthus had rather high conversion rates of 100, 93, and 87%, respectively, at a cellulase loading of 15 FPU/g glucan at 72 h. The high lignin yield of 80.76% was obtained by diluting the spent acid liquor to below the minimal hydrotrope concentration. This process promotes an innovative approach for biomass fractionation and full utilization of the components.