Study On Separation, Identification And Characteristics Of The Kitchen Garbage Degrading Bacteria

Kitchen garbage, rich in starch, cellulose, protein and other organic substances is nutrient-rich and highly biodegradable. Compost under the action of microorganisms can turn the organic matter into manure by means of mineralization and humification, which on the one hand can relieve environmental pressure, on the one hand can make kitchen garbage profitable. In recent years, researches on kitchen garbage biodegradation are increasing daily, including changing between aerobic and anaerobic compost forms, optimization of microbial vector or matrix conditioning agents and screening of high efficient degradation bacteria on kitchen garbage, etc.The nature of kitchen garbage biodegradation is a biochemical process that under the action of extracellular enzymes secreted microorganisms, organic matters are degraded into humus. Optimization of high efficient degradation bacteria can accelerate the degradation rate of organic matter and thereby shorten the time of composting process. Therefore, study of the characteristics of the degrading bacteria is particularly important, especially their salt tolerance and enzyme producing activities. However, little research is reported in this area. As such, the present study was conducted to separate bacteria selected from a commercially available microbial agent resulting in the obtaining of four kinds of bacteria useful. Mixed bacteria agent was made of the obtained bacteria and optimized matrix. Biological characteristics including salt tolerance, mobility and enzyme producing activities of the mixed kitchen garbage degradation bacteria agent were system investigated, and then simulation of the daily food waste disposing was carried out by two-stage processing mode:adding kitchen garbage daily (first stage) and static compost (second stage). During the process of composting, we monitored the pHysicochemical indicators including temperature, humidity, pH, weight change, and emissions of CO2 and observed the changes of the activities of hydrolytic and redox enzymes.The results showed that enzyme production of mixed bacteria was better than single strain; bacteria tolerated 2.5% NaCl concentration with order of Bordetella petrii> Nitrobacter hamburgensis> Ochrobactrum tritici> Backusella circina, while that of mobility with order of Bordetella petrii> Ochrobactrum tritici> Nitrobacter hamburgensis> Backusella circina. In conclusion, Backusella circina played a vital role in the initial stage of degradation. The pHysicochemical parameters during composting such as temperature, moisture, pH and microbial biomass C showed a consistent variation:rising with fluctuations at the first stage (14 days) and then decreased gradually at the second stage (28 days). The activity of invertase was stable at the late stage, suggesting that mineralization became stable during composting process. The activity of dehydrogenase decreased gradually and then stabilized in the late stage, indicating that maturity of composting was good and stable.