Research On Synergy And Process Of The Protein Of White Lees By Complex Bacteria Biotransformation

White lees is a high-quality vegetable protein material.It contains a high protein,Due to the high crude fiber content,the deep processing and utilization of it is restricted.Aimed at improving protein conversion rate of white lees' fermentation products,the tests take advantage of the synergies of candida tropicalis,bacillus subtilis and geotrichum candidum through solid state fermentation.The significance of this study is to determine the optimal strains combination and fermentation parameters.It provides the basis for the best utilization of white lees and the development of food protein.Studies includes the following five experiment parts:Experiment part 1 The screening and research on the characteristics of strainsThe purpose of this test is to find the optimal inoculation time of strains.The tablet satisfactory test is taken to observe the growth of each strain.The results show that the three strains can grow well on the medium.It means that Candida tropicalis,Bacillus subtilis and Geotrichum candidum can be used for protein conversion of white lees.We can choose them as the fermentation strains.The growth curve of the strain was determined to find the optimal inoculation time of Candida tropicalis,Bacillus subtilis and Geotrichum candidum was 20 h,24 h and 24 h.Experiment part 2 fermentation test of single strainThe purpose of this test is to provide basic reference for the mixed fermentation conditions.The single strain fermentation test studies the effects of moisture content of materials,fermentation time,inoculum on the content of crude protein(CP),true protein(TP),crude fiber(CF)of fermentation products.The results of single strain fermentation tests show that the suitable fermentation parameters are as follows: the 60% moisture content of materials,ferment 120 h with the inoculation of 20% Bacillus subtilis,the 60% moisture content of materials,ferment 72 h with the inoculation of 20% Candida tropicalis,the 60% moisture content of materials,ferment 72 h with the inoculation of 15% Geotrichum candidum.Experiment part 3 Antagonism test and fermentation test of three strainsThe purpose of this test is to determine the best utilization of distiller's grains.The antagonism test is inoculating Candida tropicalis,Bacillus subtilis and Geotrichum candidum by intersect cross-crossed on ordinary nutrient agar medium,at 30 ?with 24 h.The results show that the three strains grow well,and the intersect points don't have the phenomenon of colony atrophy and disappearance.It means that there is not antagonistic effect between the strains,and we can use them for mixed fermentation tests.The fermentation test of mixed strains is inoculating the total inoculation of 15% with each two strains(ratio of 1:1)and three strains(ratio of 1:1:1),at 30 with ? 72 h,on the basic solid medium.Compared with the blank control group,the CP,TP,CF content of two strains and three strains show that: the three strains has the best result,with 28.97% CP,22.65% TP,19.84% CF.Experiment part 4 optimization test of MediumThe purpose of this test is to provide a better culture medium for the study of the fermentation characteristics of the complex bacteria.With the indicators of the CP,TP,CF content of fermentation products,the single factor tests with three strains are taken based on four factors of pH,inoculum,addition amount of wheat bran,addition amount of urea.and the addition amount of MgSO4.And a orthogonal trial is taken to determine the optimal fermentative parameters of the medium.Finally,the verification tests are taken.Due to cost reasons,the most optimum medium conditions are: pH 7,the addition of 2.0% urea,the addition of 15% wheat bran,the addition of 0.2% MgSO4.Experiment part 5 fermentation test of mixed strains and Verification testThe purpose of this test is to determine the process parameters of solid-state fermentation with three strains.With the indicators of the CP,TP,CF content of fermentation products,the single factor tests with three strains are taken based on four factors of inoculat ratio,inoculum,fermentation time,and moisture content of materials.And a orthogonal trial is taken to determine the optimal fermentative parameters of the four factors with each factor being designed at four levels.Finally,the verification tests are taken.Due to cost reasons,the most optimum fermentation conditions are: The inoculat ratio of Bacillus subtilis,Candida tropicalis and Geotrichum candidum is 1:1:2,the inoculation of 20%,the 60% moisture content of materials with the ferment 72 h.Under these conditions,the conversion rate of protein is best,content of CP up to 32.10%,TP up to 24.89%,CF is reduced to 17.56% with a significant difference(P<0.05).The results were consistent with the orthogonal test results.In summary,we should take advantage of white lees with the synergies of complex strains through solid state fermentation.It can improve the protein content of distiller's grains to make full use of the vinasse resources and reduce environmental pollution.It has the high social and economic benefits.