Study On The Production Of Feedstuff From Bagasse By Microbial Combination Fermentation

Large amount oflignocellulosic by-products produced by industry and agriculture are difficult to degrade and the utilization rate is low,traditional treatment is piled or direct combustion which can cause environmental pollution.It has become a hot topic thatconvert lignocellulose into feedstuff with biotechnology,this is also one of the effective ways to alleviate the current food shortage and the competition between human and livestock for improving the ecological environment.However,there are bottlenecks in the conversion of lignocellulose to feedstuff,such as high crude fiber content and low protein content.Our study intends to use bagasse as a material,and we have systematically carried out a study on the production of feedstuff from bagasse by microbial combination fermentation(MCF).The main results obtained are as follows:1.The effect of different MCF on the degradation of bagasse fiber was studied,and the optimal MCF was determined.A systematic study was conducted on the individualfermentation and combined fermentation of the six strains of bacteria deposited in laboratory,such as Bacillus pumilus HG-28 with strong hemicellulase-producing ability and pectinase-producing ability,Bacillus subtilis HR-6 with hemicellulase-producing ability and cellulase-producing Aspergillus niger MX-11 an so on.It was found thatthe optimal MCFwas Bacillus pumilus HG-28 and Bacillus subtilis HR-6 were added simultaneously as the first fermentation stage,and then Aspergillus niger MX-11 and baker's yeast BH-5 were added simultaneously as the second fermentation stage.The crude fiber content of bagasse after fermentation was reduced to 30%,and the flavor was also greatly improved,and we studied the dynamic changes in the activity of a series of degrading enzymes during the fermentation process of bagasse.Thestructure and composition of bagasse were characterized by scanning electron microscopy(SEM)and X-ray diffraction(XRD),the results further clarify the degradation of bagasse by the optimal combination of microbial fermentation methods identified above.2.The effect of different bagasse particle size on the efficiency of bagasse degradation by MCF was studied.It was found that in the particle size range of 20-80 mesh,the microbial degradation effect of bagasse showed an increasing trend with decreasing particle size,but too small particle size(120 mesh)was not conducive to microbial degradation of bagasse.We further tested the dissolved oxygen levels in bagasse fermentation systems with different crushed particle sizes,it shows that in the first stage of fermentation,the 80-mesh system can maintain proper dissolved oxygen for bacterial growth and provide nutrients by bagasse degradation.In the second fermentation stage,it was also found that the 80-mesh particle size system can maintainproperdissolved oxygen and provide nutrients obtained from the degradation of bagasse,which can ensure the normal growth of the bacteria and promotedegradation of bagasse.In summary,the different bagasse particle sizecan affect the dissolved oxygen level and bagasse degradation rate by MCF,so 80 mesh was chosedas the best bagasse particle size.3.The two-stage fermentation technique of MCF of bagasse to produce feedstuff was investigated.Firstly,optimized the composition and content of nitrogen source,the ratio of material to liquid and the inoculation amount of each strain in the combined fermentation of microorganisms:0.7 g ammonium sulfate / 5 g bagasse,0.5 g soy bean cake flour / 5 g bagasse;the optimal material-liquid ratio was 5/50(w/v);Bacillus pumilus HG-28 and Bacillus subtilis HR-6 were inoculated at 10% each,Aspergillus niger MX-11 inoculation amount is 5%,baker's yeast BH-5 inoculation amount is 10%.Secondly,the amount of nitrogen source added in the second fermentation stage and fermentationterminal point were optimized,respectively: 0.7 g ammonium sulfate / 5 g bagasse,0.3 g soy bean cake flour / 5 g bagasse;the optimal fermentation terminal pointwas:The first stage fermentation was 8 h,and the second stage fermentation was 5 d.The optimized MCFtechnique was used to degrade bagasse,the crude fiber content of bagasse decreased from 49.9% to 25.1%,the degradation rate reached 37.3%,the protein content increased from 0.9% to 3.7%,and the protein improvement rate reached 69.4%,compared to the mixed fermentation of bagasse with Aspergillus niger and yeast,the crude fiber degradation rate increased by 3.7 times,and the protein increase rate reached 5.2 times.The MCFtechnique for degradingbagasse to producefeedstuff established in this study has important application value,and provides a new approach and experimental basis for the high-value comprehensive utilization of bagasse resources.