350 / 2018-07-31 22:58:56

Effects of Temperature on the Mixed Storage Fermentation Quality of Dry Maize Straw and Cabbage Waste and Microbial Community Analysis

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With the increasingly prominent problem of energy consumption and environmental pollution, biogas has become a research hotspot in the field of biomass energy. A large number of dry corn straw and cabbage waste are produced every year in China. Because of the high degree of lignification of straw, cabbage waste is prone to spoilage, and how to realize the long-term preservation and storage of dry corn straw and cabbage waste has become an important problem for the biogas engineering. The objective of this study was to investigate the effects of temperature on the mixed storage quality of dry corn straw and cabbage waste based on the ensiling theory. According to the climate conditions in Northwest of China, three temperature gradients of -9～3, 18 and 34 ℃ were designed. There are defined as low temperature (LX) group, medium temperature (MX) group and high temperature (HX) group. The experimental groups were stored for 120 d in succession, and the sensory quality, organic composition and fermentation quality were analyzed at 30 d, 60 d, 90 d and 120 d, respectively. The high-throughput sequencing technology of Illumina Miseq was used to analyze the dynamic changes of bacterial community diversity during ensiling. The results showed that the sensory evaluation of the 3 treatment groups was excellent or good, and the Fisher scores were good or very good grades. With the increase of temperature, the content of dry matter and lactic acid showed an upward trend, the content of water soluble carbohydrate decreased (except 120 d), and the ratio of ammonia nitrogen and total nitrogen also declined. The biodegradable potential in the LX group was always higher than the MX and HX groups, but the ratio of lactic acid and acetic acid and the ratio of lactic acid and total organic acid in the MX group was always higher than the LX and HX groups. The results of bacterial community diversity showed that the dominant bacteria in phylum level in the 3 treatment groups were main Proteobacteria and Firmicutes.The dominant bacteria in genus level were main Enterobacteriaceae, Lactobacillus, Carnobacterium and Leuconostoc except for some storage time. When the storage time was prolonged to 120 d, Enterobacteriaceae disappeared completely in MX and HX groups. And the relative abundance of Lactobacillus and Carnobacterium in MX group was higher than that in LX and HX groups. In conclusion, medium temperature (18±1 ℃) is more conducive to improving the mixed storage quality of dry corn straw and cabbage waste.