Comprehensive investigation of enhancing enzymatic digestion of maize straw through the synergistic pretreatment of stearyl trimethyl ammonium bromide with ortho-hydroxybenzoic acid

Maize straw underwent pretreatment with stearyl trimethyl ammonium bromide (STAB) combined with ortho -hydroxybenzoic acid (OHA), and the parameters of the pretreatment process were optimized through single-factor and orthogonal experiments. The results demonstrated that 77.2 % lignin and 92.4 % xylan were removed through the combined pretreatment at the severity factor (LogR 0 ) = 4.13, resulting in an increase in the enzymatic hydrolysis activity to 90.8 %. After pretreatment, the crystallinity of the material elevated significantly to 63.6 %, the surface structure became rough, and the accessibility elevated to 667.4 mg/g. These positive changes jointly improved the efficiency of enzymatic hydrolysis. By-products including 3.7 g/L xylo -oligosaccharides, 1.1 g/L 5-hydroxymethylfurfural, 0.6 g/L furfural, 1.2 g/L formic acid, and 1.5 g/L acetic acid co-produced during STAB+OHA combination pretreatment. Meanwhile, the reusability experiment of up to 5 cycles confirmed the sustainable utilization of this combined pretreatment system. This pretreatment technology theoretically facilitated the diversification of fuel and chemical production.