Effects of recombinant swollenin on the enzymatic hydrolysis， rumen fermentation， and rumen microbiota during in vitro incubation of agricultural straws.

An experiment was conducted to determine the effects of swollenin on the enzymatic hydrolysis and in vitro rumen microbial fermentation of agricultural straws. The swollenin from Trichoderma reesei was produced in Pichia pastoris in current study. The recombinant protein caused an obvious disruption on filter paper and slight increase in reducing sugars release when treating xylan， Avicel， rice straw， wheat straw， and corn straw. Simultaneous incubation of swollenin with fibrolytic enzyme resulted in a significant synergistic activity on disruption of filter paper and hydrolysis of above-mentioned substrates. During in vitro rumen fermentation of three straw diets， the dry matter digestibility， acetate production， microbial protein synthesis， and fibrolytic bacterial population were increased by swollenin. This study demonstrates that swollenin could enhance the enzymatic hydrolysis and in vitro ruminal fermentation of agricultural straws， showing the potential of swollenin for improving the utilization of agricultural straws in ruminants.