Preparation Method Of High Temperature Composting Decomposing Bacterium Agent For Camphor Garden Waste And Composting Application

Camphora tree is the main garden planting tree in the southern region of China,and its greening waste continues to increase.Camphor branches and leaves contain camphor which has the effect of inhibiting microorganisms and plant growth,etc.,which greatly restricts its reuse.Camphora is the main garden planting tree in the southern region of China,and its greening waste continues to increase.Camphora branches and leaves contain ecotoxic substances with microbial and plant growth inhibiting effects that greatly limit their reuse.Efficient treatment of garden waste has become one of the main greening problem bottlenecks in China.In addition,kitchen waste accounts for 30%to 50%of China’s municipal waste,containing a variety of microorganisms and a large amount of organic matter,easy to decay,odor and deterioration.Co-composting of garden waste with kitchen waste is a very effective treatment method and can reduce the harm of kitchen waste.However,garden waste is difficult to be degraded because it contains a large amount of lignin and cellulose,which requires a long composting time and low level of decay.Detoxifying the bacteriostatic substances in camphor leaves,improving the decomposition efficiency of lignin and cellulose,and raising the composting temperature are the keys to treating garden waste efficiently.In this study,the functional bacteria with high temperature tolerance,which can detoxify camphora inhibition,plant inhibition and lignin and cellulose degradation were screened out from the samples of high temperature stage of camphora garden waste and kitchen waste composting by traditional culture method,and the strains were identified by their 16S r DNA sequence analysis for small-scale fermentation production;the liquid bacterial agent was added to the garden waste and kitchen waste for co-composting,and its effect on composting effect was explored We also explored the microbial diversity analysis to explore the microbial functions and the optimization of composting conditions.By adjusting different ratios of camphor garden waste to kitchen waste,different initial moisture levels of the compost,and adjusting the initial p H of the compost,suitable initial physicochemical properties of camphor garden waste compost were determined,i.e.a 2:3 ratio of camphora garden waste to kitchen waste,an initial moisture content of 60%of the compost,and the addition of 1%（w/w）lime.A strain of Caldibacillus thermoamylovorans MB12B was screened using a sample of high temperature garden compost as the source and the water leachate from the camphor garden waste as the sole carbon source.It also eliminates the inhibition of plant growth by aqueous extracts of camphora garden waste.This strain can significantly drive the composting system of garden waste-kitchen waste containing camphora waste.The preparation of MB12B high-temperature compost liquid bacterium was optimized using a single-factor test,Plackett-Burman experiment,steepest climb experiment methodology.The optimum conditions were peanut flour 10.5 g,sucrose 10.0g,Mn SO₄ 0.03 g,Mg SO₄ 0.4 g,Na₂HPO₄ 0.4 g,Na H₂PO₄ 0.5 g,incubation temperature37°C,inoculum 5.7%v/v,p H 7.5.MB12B bacterial agent can effectively lift the ecotoxic substances contained in camphor garden waste in the composting system,and enhance the composting efficiency of the aerobic high-temperature composting system of garden waste-kitchen waste from camphor waste.High-throughput sequencing showed that:a significant enrichment of the temperature-related genera Caldibacillus,Bacillus and Ureibacillus and a significant increase in temperature during the thermophilic phase of composting.Eventually,the water conductivity of the compost was significantly reduced,and high-throughput sequencing showed an enrichment of Sphingobacterium,which is related to humus formation,and an increase of 18.0%and 44.1%in the germination index and humus of the compost products,indicating that the addition of MB12B bacterial agent improved the composting efficiency of the aerobic hyperthermophile composting system of garden waste from camphor waste to kitchen waste.The addition of MB12B bacterial agent reduced CH₄ and NH₃ emissions by 61.9%and 37.6%.After high temperature compost decay,the compost product had an organic matter mass fraction of 57.5%,a total nutrient content of 7.0%and a moisture mass fraction of29.1%,meeting the requirements of organic fertilizer standard NY/T 525-2021.The ryegrass pot trials showed that the application of 10%compost product increased the weight of above and below ground parts of ryegrass by 81.7%and 68.9%respectively,and plant length by 65.8%and 51.9%respectively,compared to the blank control,which was almost equivalent to the effect of chemical fertilizer.