Study On Pretreatment Of Cornstalk And Feed Production Of Multi-strain Fermentation

Straw is an abundant and not efficient used agricultural resource in China.Straw must be pretreated before the utilization as it was composed by cellulose,hemicellulose and lignin.The cormstalk was used for the research of NH₃ pretreatment and combined NH₃ and HZOZ pretreatment.The factors in NH₃ pretreatment was studied with a determination of enzyme hydrolysis reducing sugar yield after pretreated.On this basis,the effect of combined treatment of NH₃ and H₂O₂ on cornstalk was studied.In the end,the research on feed conversion and methane fermentation was carried out with the pretreatment of cornstalk as substrate.The results were evaluated by methane fermentation experiments.The results were showed as follows:1.Four factors of pretreatment,the time,NH₃ concentration,temperature and moisture were studied,and the optimization condition were pretreated in 2 days with the temperature of 50℃ and 3%NH₃,30%moisture.But the result of orthogonal experiment with three factors in three levels showed that the optimization condition of NH₃ pretreatment was pretreated in 4 days with 50℃ and 3%NH₃,and in this condition the enzyme hydrolysis reducing sugar yield was 0.452 g/g,49.7%was increased compared with the untreated control group which was 0.302g/g.2.The combined NH₃ and H₂O₂ pretreatment was studied by orthogonal experiment.The best condition of the combined NH₃ and H₂O₂ pretreatment were taken out in 40 ℃with 1.5%NH₃ and moisture 30%for 4 days and then H₂O₂ pretreatment was in ambient temperature with 2%H₂O₂ for 2 days.In this condition the enzyme hydrolysis reducing sugar yield was 0.532 g/g which was 17.7%higher than the NH₃ pretreatment.3.The results of fermentation of raw materials are as follows:the mixed microorganism fermentation showed that after the NH₃ pretreatment only,the total count of Candia intermedia FL023#and Lactobacillus pentose FL0421#of NH₃ pretreatment only and without pretreated cornstalk were 10.2×10⁸CFU/g and 3×10⁸ CFU/g,11×10⁸CFU/g and 6×10⁸ CFU/g;the mix microorganism fermentation using FL023#and FL0421#with combined NH₃ and H₂O₂ pretreated cornstalk were 35.4×10⁸ CFU/g and 208.5×10⁸ CFU/g which was 3 times and 19 times higher than that of NH₃ treatment only.4.The observation of NH₃ pretreated cornstalk using phase contrast microscope and scanning tunneling microscope showed the fiber of cellulose was treated with a large amount of morphological changes which mean more easily to be approached by enzyme molecule,and on the contrast,the cormstalk was intact.5.The methane fermentation was taken out using the cornstalk without pretreatment,pretreated with NH₃ and pretreated with NH₃ and H₂O₂.The production of methane from three substrate was 91.2 mL/g,287 mL/g and 316 mL/g respectively.Compare with the cormstalk pretreated with NH₃ only,the pretreated cornstalk with NH₃ and H₂O₂,the methane production was 10%higher.6.Afner the pretreatment of cormstalk by microbial transformation,the experimental results show good palatability,beef color,nornal posture in the beef cattle feeding,also the stool has a certain improvement.