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A Study On Screening Of Decomposing Fungi And Compound Agent For The Garden Waste Composting

Posted on:2021-02-02Degree:MasterType:Thesis
Country:ChinaCandidate:Y KangFull Text:PDF
GTID:2393330611969177Subject:Soil science
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With the continuous improvement of urban green rate,more and more landscaping waste needs to be treated efficiently and innocently.Composting is one of the main means of harmless treatment.It is the focus of aerobic composting to accelerate the process of composting and improve the quality of composting products.Efficient lignin decomposing fungi were screened from aerobic composting materials of landscaping waste,and ITS sequencing was used to identify the microbial species,so as to explore the decomposing effect of landscaping waste produced by common tree species in Beijing.From the 4 strains of cellulose decomposing bacteria in the laboratory,the microorganisms without antagonistic reaction and nutritional competition with lignin decomposing fungi were selected.By means of regression orthogonal design experiment,the optimal ratio between two microorganisms was obtained through the fitting equation,which was used to allocate landscaping waste to add compound bacteria agent,and the practical effect of the compound bacteria agent was verified in the compost of landscaping waste.The experimental results are as follows:?1?a highly efficient lignin decomposition strain was selected from the composting materials of landscaping waste.Through morphological observation and ITS sequence analysis,it was identified as Aspergillus conformis,which could be used to explore the principle of lignin decomposition by fungi and produce lignin decomposition agents.Aspergillus nidulans had a better lignin decomposition effect on the landscaping waste produced by common tree species in Beijing,and the lignin decomposition rate of the leaves,branches of Euonymus japonicus?Sabina chinensis and Forsythia suspensa increased by 20.40%,22.44%,29.90%,25.28%and 15.77%respectively after 40 days.?2?microbial antagonism experiment there was not antagonism between lignin degrading fungi No.11and cellulose degrading bacteria b1-b4,but there was nutritional competition between them and bacteria B1 and B3.Therefore,the cellulose degrading bacterium B2?bacillus subtilis?was selected as the target bacteria,and fungus no.11 was used as the source of the subsequent preparation of the compound bacteria agent.Through simulated composting experiment,the regression equation is finally fitted as Y=0.533+0.068X1-0.044X12+0.082X2-0.060X22,theoretically the maximum comprehensive degradation rate of lignin cellulose was 58.7%,at which time the concentration of fungus solution was 4107cfu/m L,and the addition amount was 0.77ml per 100g dry weight.The concentration of bacterial solution was6108cfu/m L,and the additive amount was 0.68ml per 100g dry weight.?3?experimental data show that the high temperature period of the reactor can be prolonged by the addition of bacterial agent.Compared with the bacterial agent with single microorganism,the compound bacterial agent showed significant improvement in lignin decomposition rate,cellulose decomposition rate,humus carbon content,fulvic acid carbon content and comprehensive decomposition rate.In terms of p H value,EC value and humic acid carbon content,there was no significant difference between the compound bacterial agent and the single microbial agent.The actual decomposition rate of lignin and cellulose in the experimental group was 37.4%,which was lower than the theoretical decomposition rate of 58.7%.However,compared with the non-application of bacterial agent and other bacterial agent,the compound bacterial agent still has the effect of improving the composting products and promoting the composting process.
Keywords/Search Tags:Aspergillus nidulans(Eidam) G.Winter, garden waste, composting, Quadratic regression orthogonal design, compound bacteria agent
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