Optimization Of The Food Waste Biochemical Degradation Process And Research On Its Microbial Diversity

Nowadays,food waste can be effectively solved by biochemical degradation.The food waste biochemical degradation process is dependent on the suitable degradation equipment and various microorganisms.Microorganisms are main functional factors,the equipment is the prerequisite for the growth of microorganisms.In this research,firstly,we have optimized the main process parameters of the food waste biochemical processor,which obtained the best combination parameters and provided a technical reference for the setting.Secondly,the changes in physicochemical properties and enzyme activities of the food wastes throughout the biochemical degradation process were explored,which provided a basis for degradation.Finally,from two perspectives of the number and diversity,the change of microorganisms in the biochemical degradation of food waste was revealed,which provided a theoretical reference for the selection and optimization of food waste biochemical degradation.The main results show that:1.Combining One-factor experimental design with Response Surface Methodology,the results showed that the degradation rate of food waste would remain in its maximum when the temperature was 45°C,humidity was 55% and inoculation was 2.3:1.The influencing sequence of these three factors was temperature,inoculation,humidity.2.In the 24 h biochemical degradation of food waste,the temperature increased rapidly,and then decreased slightly,reached the maximum at 8h.The pH value decreased first and then increased,reached the lowest value at 4h.The water content increased first and then decreased,reached the maximum value at 4h.The content of easily degradable organic matter decreased continuously,decreased rapidly in 2~8h.The activity of lipase,amylase,protease and cellulase increased first and then decreased,reached the maximum at 4h,8h,8h and 8h respectively.All the above indicators tended to be stable after 24 h.3.According to the traditional culture microbial studies,it was found that the number of bacteria,actinomycetes and fungi was all increased first and then decreased,reached the maximum at 6h,8h and 2h respectively,but the number of fungi and actinomycetes were always lower than that of bacteria by 2~3 orders of magnitude.4.According to the high-throughput sequencing technology,it was found that during the whole biochemical degradation of the food waste,for bacteria,its community diversity and richness increased first and then decreased.Meanwhile,there were obvious structural changes of dominant populations.The result indicated that 156 OTUs were obtained from all samples.The Lactobacillus,Bifidobacterium,Xylella,Corynebacterium and Corynebacterium 1 were all dominant genus in each period.The Lactobacillus and Bifidobacterium continued to decrease.The Corynebacterium and Corynebacterium 1 increased.The Xylella increased first and then decreased.For fungi,during biochemical degradation,its community diversity and composition were always simpler than bacteria.The community diversity and richness decreased gradually,but the community composition did not change significantly.The result indicated that 28 OTUs were obtained from all samples.The Candida were all dominant genus in each period,it has accounted for more than 95%of the whole.In addition,the Geotrichum Aspergillus,Trichosporon,Penicillium were also detected.The Aspergillus decreased gradually,Aspergillus increased first and then decreased.