A Study Of Utilizing The Mixed Bacterium Solid Fermentation Cassava Dregs Produced Bacterial Protein Feed

Cassava dregs is the residue after the extraction of amylum in productions using cassava as the raw material.Cassava dregs is abandoned in many factories thus cause environment pollution.Through microbe processing,cassava dregs can be changed into feed ingredients of livestock and poultry.In this way,as an industrial waste cassava dregs is fully used which is helpful for environment protection and at the same time significantly reduced the feeding cost.Therefore,cassava dregs fermentation is scientificly valuable and has a great developing prospect in the market at the same time.This study aim was to utilize the cassava dregs fermentation to produce bacterial protein feed.The main results as follows.1.Selection of strains,their combination and inoculation proportionOne strain of aspergillus niger,seven strains of trichoderma viride,two strains of yeast and four strains of bacillus subtilis were adopted in this study.Solid fermentation were conducted under the same fermentation condition and the content of crude protein of products was tested for the selection of single strain.According to the results,the strain numbered as 93270 in the seven strains of trichoderma viride and the highest amount of crude protein was 10.4%after fermentation;the strain numbered as AY920 in the two strains of yeast and the highest amount of crude protein was 12.4%;the strain numbered as 7# in the four strains of bacillus subtilis and the highest amount of crude protein production was 8.7%.The selected four strains were used to conduct 11 fermentation experiments of different combinations.The results showed that the combination of aspergillus niger, trichoderma viride 93270 and yeast AY920 was better than otheirs,the highest amount of crude protein production was 14.7%.The comfirmation of the best inoculation proportion was carried out after the best combination was comfirmationed,in these fermentation experiments inoculation proportions were conducted and they were 1:1:1,1:2:2,1:3:3,2:1:2,2:2:3,2:3:1,3:1:3, 3:2:1 and 3:3:2 respectively.The results showed that the most suitable proportion was 2:2:3 and its content of crude protein was 14.5%.2.Optimization of the culture medium and conditions of fermentationAn orthogonal experiment of four factors at four levels was conducted that the factors and levels were as following:fermentation temperature(25℃,30℃,35℃, 40℃),fermentation time(1d,3d,5d,7d),the amount of nitrogen source(5%,15%,20%, 25%),the amount of the strains(1%,2%,3%,4%).The results showed that the optimium conditions of fermentation were as following.The inoculation amount of liquid seeds was 2%.The added amount of nitrogen source was 20%.The fermentation temperature was at 35℃and the fermentation time was 3d.The test of products after the fermentation showed that content of crude protein increased from 7.6%to 18.4%and several important amino acids increased also.3.Feeding test of fermented cassava dregs on commercial pigs The enlarged fermentation was carried out at the optimium fermentaion conditions. The fermentaioneed products were dried and mixed into complete feed with the content of 15%.The pigs in the experiment were divided into three major groups according to different growth stages.They were later stage of piglets(31kg±1kg),earlier stage of finishing(43kg±1kg) and later stage of finishing(70kg±1kg).Each major group was divided into three small groups oncf more and named as groupⅠ,ⅡandⅢ.The groupⅡ,Ⅲwere experiment groups and the groupⅠwas the control group.The results showed that the daily weight gain had no significant difference between experiment groups and the corresponding control group,but the cost of daily rations for the three major groups was reduced by 62.5 yuan,170.1 yuan and 89.3 yuan respectively.