Abstract: The aim of this study was to improve the efficiency of microbial fermentation and extraction of corn cob xylan,In this study,the xylan in corncob was extracted by microbial fermentation combined with H₂O₂ pretreatment,then microstructure of corn cob was observed by scanning electron microscope (SEM) to analysis the reason of increased extraction efficiency of corn cob xylan after H₂O₂ pre-treatment.The results showed that the content of xylan was up to 40.21±0.21 mg/g when corncob was pretreated with 4% H₂O₂ for 1 h,which increased by 87.72% compared to untreated group.Microbial fermentation combined with 4% H₂O₂ pretreatment significantly increased the content of corn cob xylan (52.72 mg/g),which increased by 186.67% compared to untreated group.Optimized the extraction conditions of corncob xylan after microbial fermentation combined with H₂O₂ pretreatment based on response surface methodology,and obtained the optimal medium substrate contained water content 50 %,urea 0.25% and glucose 0.75%.Under these conditions,the xylan content reached up to 70.84 mg/g ,which increased by 249.82% compared to unfermented corn cob.SEM images showed that the structure of the corn cob became loose after being pretreated by H₂O₂,and larger holes appeared on the surface of corn cob after microbial fermentation combined with H₂O₂ pretreatment.In conclusion,H₂O₂ pretreatment can improve the structure of corn cob,promote microbial fermentation,and increased extraction efficiency of corn cob xylan,this study will provide a reference for the efficient exploitation and utilization of corn cob xylan.

Key words: corncob, xylan, microbial fermentation, H₂O₂ pre-treatment