Abstract: This experiment was conducted to investigate the effect of lactic acid bacteria and acidic protease solid-state fermentation on crude protein,pH,acidity and antinutritional factor content of soybean meal,cottonseed meal and rapeseed meal.The total fermentation time was 72 hours,and collected samples in every 12 hours (collected samples in every 24 hours for exterminating crude protein).The results showed that the crude protein content,and acidity of soybean meal,cottonseed and rapeseed meal were increase in different extents,and the pH was declined by lactic acid bacteria and acidic protease compound solid-state fermentation.The contents of trypsin inhibitor,lupeose and raffinose in soybean meal were remarkably declined,and the contents of tannin in cottonseed meal and the contents of ITC and OZT in rapeseed meal were declined in varying degrees.But the degradation ability of phytic acid and free gossypol was very limited.It was concluded that the lactic acid bacteria and acidic protease compound solid-state fermentation could improve the crude protein content and acidity,decrease the pH of fermentation substrate,and could remarkable decline the contents of antinutritional factor contents of soybean meal,cottonseed meal and rapeseed meal,so obviously improve the nutritional value.

Key words: lactic acid bacteria; acidic protease; soybean meal; cottonseed meal; rapeseed meal; fermentation; enzymolysis