Study On Immobilization Of Food Waste Degrading Microbial Agents

With the rapid economic development,the problem of the disposal of food waste has become more and more prominent.Because of the biodegradable characteristics of food waste,the most environmentally friendly treatment method is microbial degradation,which not only solves the problem of environmental pollution,but also produces economic benefits.Microbial agents are required for the microbial degradation of food waste,and the production and use of microbial agents are generally immobilized because immobilized agents have the advantages of preservation and transportation.In this paper,the immobilization study was carried out with the strains selected by the same research group.The immobilization materials,drying protection agent,drying and preservation parameters of the microbial agent were studied.1.Through a single factor experiment,the factors such as carrier type,carrier particle size,carrier addition ratio,immobilization time,immobilization temperature,immobilization p H,immobilization rotation speed and other factors were studied.The optimal immobilization conditions for bacteria were 50 mesh corn stover,2% carrier ratio,1% inoculum,35 ?,160 rpm and immobilization time of 12 h.The optimal immobilization conditions of the fungus were 50 mesh coconut bran,2% carrier ratio,1% inoculation volume,25 ?,120 rpm,immobilization time of 24 h.2.Through a single factor experiment,the application parameters of the protective agent in the drying treatment of the bacteria and fungus immobilized bacterial agent were studied,the suitable types of protective agent,addition ratio,action temperature,and p H of the protective agent of the bacterial and fungal agent were determined respectively.The best conditions for the drying effect of immobilized bacteria are 7% mixed protective agent(1:1:1 starch,skimmed milk powder and dextrin),p H=8.0,50 ?,160 rpm and the mixing time is 15 min.The best conditions for lyophilization protection of immobilized bacteria are 5% mixedprotective agent(1:1:1 fructose,sucrose and trehalose),p H=7.0,40 ?,160 rpm and the mixing time is 15 min.The best conditions for the drying protection of immobilized fungi are: 5% mixed protective agent(1:1:1 starch,skimmed milk powder and trehalose),p H=7.0,40 ?,120 rpm and the mixing time is 30 min.The best conditions for freeze-drying protection of immobilized fungi are: 7% mixed protective agent(1:1:1 trehalose,lactose,fructose),p H= 6.0,30 ?,120 rpm and the mixing time is 30 min.3.Through a single factor experiment,the parameters of the fungus during drying and preservation were studied,and the drying temperature,pre-freezing temperature and time,moisture content after drying,preservation temperature,etc.were determined respectively.The optimal drying condition for immobilized bacteria is 60 ? to a final moisture content of 5 %.The optimal freeze-drying condition is to pre-freeze at-80 ? for 1 h,and then freeze-dry to a final moisture content of 5%.The optimal drying condition for immobilized fungi is 60 ? to a final moisture content of4 %.The optimal freeze-drying condition is to pre-freeze at-80 ? for 1 h,and then freeze-dry to a final moisture content of 4 %.The best storage temperature is 4 ?.4.The application of immobilized food waste degrading bacteria agent was studied.Taking unimmobilized bacteria agent as a control,both immobilized and unimmobilized bacteria agents were prepared immediately after drying and stored for3 months after preparation.Two states of fungus.Then put different fungicides into the food waste,and measure the changes of p H,temperature,water content,total organic matter and biomass.The results show that the initial biomass of the immobilized microbial inoculum is much greater than that of the unimmobilized microbial inoculum,and the rate of increase of the immobilized microbial inoculum is greater than that of the unimmobilized microbial inoculum.Because of the metabolic heat generation,the temperature of the waste treated by the immobilized bacteria agent is higher than that of the unimmobilized bacteria agent and the rate of water evaporation and organic matter degradation is also faster.Therefore,the rate of degradation of food waste by immobilized bacteria is higher than that of unimmobilized.