Effect of pretreatment on solid-state fermentation of natural lignocellulose by Aspergillus fumigatus G-13

In order to efficiently utilize lignocellulosic materials, different treatment methods were used to pretreat lignin. In this research, three pretreatment methods, physical pretreatment, chemical pretreatment, and combined physical and chemical pretreatment, were used to investigate the effect of different pretreatment ways on the solid-state fermentation of lignocellulosic biomass (straw, locust, and walnut shell) by Aspergillus fumigatus G-13, and the physical and chemical structure changes of the materials before and after pretreatment and fermentation were also analyzed. The study concluded that physical-chemical combined pretreatment was most beneficial to enzyme production. The optimized pretreatment method is that the particle size is 60-80 mesh, the solid-to-liquid volume ratio is 1:1.5, and the 8% Ca(OH)(2) solution is pretreated at 60 degrees C for 48 h. The maximum enzyme activity was increased by 4.81-28.91 times for the locust, with 7.68-35.20 times for the walnut shell. Research indicated that the combined pretreatment could change the crystallinity and microcrystalline size of lignocellulose samples. In addition, it broke the ester and ether bonds between lignin and hemicellulose as well as weakened the hydrogen bond between hemicellulose and cellulose.