Experimental Research On Several Problems Of Food Wastes Microbial Degradation

Food wastes are kitchen leftover and hogwash generated in kitchen and eatery,and also rare organic nourishments. The food wastes are large in amount, dispersed, decayed easily, stinks. If the food wastes do not be treated in time, it will pollute road, atmosphere and river system, moreover propagate insects and rats.The food wastes can be degraded into organic fertilizer with microbial degradation timely, rapidly, efficiently. It will be an ideal disposal method of the food wastes which can make the food wastes innocuity, reducing and recycling, moreover intending direction in future.It has very important social significance, enormous economical benefit and environmental benefit that researching disposal process and equipment of the food wastes. the experimental research and productions has been expatiated as follows:(1) Aiming at the three important compositions,Making use of kinds of the corresponding culture mediums to screen strains on basis of collecting abroadly the sample of soil and dirt mud. By the way of screening,isolation and purification,domestication and culture, three kinds of high-efficiency degradation strains of food wastes were gained.As is the following:1) Three kinds of high-efficiency strainss of degrading starch were screened,they were respectively DC,DT and DN.2) Two kinds of high-efficiency strains of degrading fat were screened, they were respectively YC and YT.3) Two kinds of high-efficiency strains of degrading protein were screened, they were respectively B1 and B2.(2) By the analysis of strains morphology and biochemical properties,the strains were respectively Aspergillus, Candida, Bacillus endospores, Pseudomonas, Actinomyces and Mucor. As is the following:1) The strains that can degrade starch efficiently were mainly DC,DT and DN,they were respectively Aspergillus and Candida.2) The strains that can degrade fat efficiently were mainly YC and YT, they were respectively Bacillus subtilis and Pseudomonas.3) The strains that can degrade protein efficiently were mainly B1 and B2, they were respectively Actinomyces and Mucor.(3) By the experiment research on the degrading effect of the three kinds of strainss,the high-efficiency strains of degrading starch, fat and protein show different degrading rule.As is the following:1) The degrading effect of starch was obvious at the degrading prophase of food wastes of a week.The degradation could quickly reach more than 70% by the degrading effect of both the first day and the second day in a week.The degradation could highly reach 80.9% after seven days.2) The degrading effect of fat was obvious at the degrading metaphase of food wastes of a week.The degradation could quickly reach more than 40% from the second day to the fifth day in a week.The degradation could highly reach 49.2% after seven days.3) The degrading effect of protein was also obvious at the degrading metaphase of food wastes of a week.The degradation could quickly reach more than 40% from the second day to the fourth day in a week.The degradation could highly reach 45.2% after seven days. (4)Through the single factor test,the thesis researched the influence of the main four factors to the degradation of organic matter of food wastes after three days. As is the following:1) The influence with reaction temperature.At 40℃,50℃and 60℃, the variety trend of degradation of organic matter of food wastes was nearly same in three days,Moreover the result of the degradation of organic matter was nearly same after three days.Considering the effect of temperature to the growth of degradation strains,the optimum temperature was 40℃,and the degradation of organic matter highly reached 36% after three days.2) The influence with inoculum. When the inoculum were 7% and 9%, the the variety trend of degradation of organic matter of food wastes was nearly same in three days ,and the result of the degradation of organic matter was nearly same after three days. Considering to reduce the cost of of degradation strains, 7% was choosed as the optimum inoculum,the degradation of organic matter highly reached 37.6% after three days.3) The influence with C/N. When the C/N were 30:1,40:1 and 50:1, the the variety trend of degradation of organic matter of food wastes was nearly same in three days ,and the result of the degradation of organic matter was nearly same after three days. Considering the effect of C/N to the growth of degradation strains, the optimum C/N was 30:1, the degradation of organic matter highly reached 38.4% after three days.4) The influence with initial containing moisture.When the initial containing moisture was from 40% to 60%, the degradation of organic matter of food wastes made obvious effect in three days. When the initial containing moisture was 60%, the degradation of organic matter highly reached 38.6% after three days.When the initial containing moisture was lower than 40% or higher than 60%,the degradation of organic matter comparatively decreased.So the initial containing moisture had they were respectively Bl and B2,(2) By the analysis of strains morphology and biochemical properties,the strains were respectively Aspergillus, Candida, Bacillus endospores, Pseudomonas, Actinomyces and Mucor. As is the following:1) The strains that can degrade starch efficiently were mainly DC,DT and DN,they were respectively Aspergillus and Candida.2) The strains that can degrade fat efficiently were mainly YC and YT, they were respectively Bacillus subtilis and Pseudomonas.3) The strains that can degrade protein efficiently were mainly Bl and B2, they were respectively Actinomyces and Mucor.(3) By the experiment research on the degrading effect of the three kinds of strainss,the high-efficiency strains of degrading starch, fat and protein show different degrading rule.As is the following:1) The degrading effect of starch was obvious at the degrading prophase of food wastes of a week.The degradation could quickly reach more than 70% by the degrading effect of both the first day and the second day in a week.The degradation could highly reach 80.9% after seven days.2) The degrading effect of fat was obvious at the degrading metaphase of food wastes of a week.The degradation could quickly reach more than 40% from the second day to the fifth day in a week.The degradation could highly reach 49.2% after seven days.3) The degrading effect of protein was also obvious at the degrading metaphase of food wastes of a week.The degradation could quickly reach more than 40% from the second day to the fourth day in a week.The degradation could highly reach 45,.2% after seven days. (4)Through the single factor test,the thesis researched the influence of the main four factors to the degradation of organic matter of food wastes after three days. As is the following:1) The influence with reaction temperature.At 40°C,50°Cand 60°C, the variety trend of degradation of organic matter of food wastes was nearly same in three days,Moreover the result of the degradation of organic matter was nearly same after three days.Considering the effect of temperature to the growth of degradation strains,the optimum temperature was 40°C,and the degradation of organic matter highly reached 36% after three days.2) The influence with inoculum. When the inoculum were 7% and 9%, the the variety trend of degradation of organic matter of food wastes was nearly same in three days ,and the result of the degradation of organic matter was nearly same after three days. Considering to reduce the cost of of degradation strains, 7% was choosed as the optimum inoculum,the degradation of organic matter highly reached 37.6% after three days.3) The influence with C/N. When the C/N were 30:1,40:1 and 50:1, the the variety trend of degradation of organic matter of food wastes was nearly same in three days ,and the result of the degradation of organic matter was nearly same after three days. Considering the effect of C/N to the growth of degradation strains, the optimum C/N was 30:1, the degradation of organic matter highly reached 38.4% after three days.4) The influence with initial containing moisture.When the initial containing moisture was from 40% to 60%, the degradation of organic matter of food wastes made obvious effect in three days. When the initial containing moisture was 60%, the degradation of organic matter highly reached 38.6% after three days.When the initial containing moisture was lower than 40% or higher than 60%,the degradation of organic matter comparatively decreased.So the initial containing moisture had greatly influence on the degradation of organic matter.(5) The degradation of the food wastes was related with reaction temperature(Z1), inoculum(Z2), C/N(Z3) and initial containing moisture(Z4). In order to define the optimum combination of the Anaerobic degradation, the degradation process of food wastes was researched experimentally by secondary cross circumvolve combination test.1) The sequence of these 4 influence factors was x₄>x₂>x₃>x₁,they are (Z4) initial containing moisture,(Z2)inoculum, (Z3) C/N and (Z1) reaction temperature.2) The optimum combination of these factors was x₁=0,x₂=r=2,x₃=r=2,x₄=1, It means that reaction temperature is 40℃, inoculum is 9%,C/N is 50:1, initial containing moisture is 60%.In the three days,the maximal degradation of organic matter was 56.08%.3) At the prominence levelα=0.20, the regression equation is :The thesis had screened high-efficiency degradation strains of food wastes by the researches of hereinbefore,and made certain the type of the strains by judging to the degradation strains.at the same time,the thesis had also researched on the degradation effect of high-efficiency degradation strains. The thesis had reviewed the rule of the degradation of organic matter adapting to reaction temperature, inoculum, C/N ,initial containing moisture and time in the Anaerobic degradation process of food wastes by the single factor test . By the secondary cross circumvolve combination test,the thesis has got the sequence of these 4 influence factors and defined the optimum combination, the maximal degradation and the regression equation of degradation process,which consequently supplied helpful foundation of the research of the automatic test and control of equipments of food wastes.In particular,the well degradation effect of food wastes in the Anaerobic degradation in three days has greatly shortened the time of degradation and improved the degradation of food wastes. and made the food wastes innocuity, reducing and recycling at a certain extent. It not only can avoid polluting environment, but also can decrease the disposal quantity and cost of MSW,and also supply science foundation of the research of the process and equipment of microbial degradation of food wastes.