Preparation Of Solid Microbial Agent And Its Application In Aerobic Composting Of Macromycin Residue

With the continuous development of the antibiotic pharmaceutical industry,if a large number of antibiotics and their products（bacterial residues）are not treated,they will not only pollute the environment,but also cause the production of super bacteria.Moreover,the bacterial residue contains a large amount of protein,nutrient elements and trace elements,so how to recycle the problem of antibiotic residues in the antibiotic bacterial residue has become a problem to be solved.Aerobic composting has become an effective way to achieve antibiotic residue composting in recent years.Although aerobic composting can remove antibiotics to a certain extent,the traditional composting process is limited by its own.It may not be able to completely remove antibiotics or the degradation rate of antibiotics.high.Studies have found that the addition of microorganisms can increase the degradation rate of antibiotics,improve the quality of compost products and shorten the composting cycle.In recent years,solid bacterial agents have received widespread attention due to their stable performance and convenient transportation.Therefore,this study mainly uses spectinomycin residue and straw as composting raw materials,and uses a composite microbial inoculant composed of existing strains in the laboratory to optimize the formulation of the inoculum and fermentation and culture conditions to achieve high-density mixed bacteria culture;-Embedded"technology to obtain the preparation method of the solid microbial inoculum;further monitor and analyze the product quality of the prepared solid inoculum,and carry out the actual composting effect of the solid inoculum stored for 90 days.The above research results can provide references for the preparation and industrial application of solid microbial inoculants for composting antibiotic slag in the future,and have important practical application value.（1）Feasibility study of spectinomycin composting and optimization of bacterial formulation.The existing strains of the research group were used to study its effect on spectinomycin composting,and the formula of the inoculum was optimized and additional verification experiments were carried out.The results show that spectinomycin can be used to remove antibiotic residues through high-temperature aerobic composting,and the removal rate can reach 100%,and the microbial agent can play a role in spectinomycin composting,but the effect is not obvious.The formulation of the inoculum was optimized,and it was found that the seven bacteria in the formula had no antagonistic effect on spectinomycin.The strains were B402,B409,and B508.Therefore,the optimized formulation of the inoculum was determined to be B402,B409,and B508,and the second composting was added.Verification.The verification results show that the optimized bacterial liquid is added to the composting system,the high temperature lasts longer,and the highest temperature is 65.33 ^oC,which is higher than the highest temperature before optimization of 60.34 ^oC,and the degradation rate of organic matter is increased by 20.30%and The maturity is higher,which proves that the optimized bacterial formulation is meaningful.（2）Optimization of the cultivation conditions of the formula strains.A single optimization of the medium of the three strains was performed,and the optimization results showed that based on the later mixed culture,the best carbon source for B402,B409,and B508 was 15 g/L glucose,and the best nitrogen source was 15 g/L Yeast powder.In the early stage of medium optimization,the sequence co-cultivation based on the growth curve was selected,and the fermenter was expanded in the later stage to further increase the concentration of the bacterial solution.The results show that the best culture method on the fermentor is to use sequence co-cultivation at 40 ^oC,the number of viable bacteria obtained at this time is 9×10⁹ CFU/m L,and the biomass is 20.31 g/L.The fermenter is fed in batches,that is,the carbon source is fed at 7h.At this time,the maximum biomass that can be obtained is 28 g/L,and the number of viable bacteria is 14.1 billion CFU/m L.The number of viable bacteria increased by 56.57%.Orthogonal experiments were performed on the fermentation parameters of the fermentor,and the optimal production process parameters were determined to be p H 7.5,rotation speed 250r/min,and DO aeration ratio 2.25 vvm.At this time,the biomass obtained was 34.63 g/L,which was increased before optimization.The number of viable bacteria was 2.21×10¹⁰ CFU/m L,which was 56.74%higher than that before optimization（9×10⁹CFU/m L）,and the spore rate could reach 65.38%.（3）"Adsorption-embedding"method to prepare solid bacterial agents.The new porous starch is used as the adsorbent.When the ratio of bacterial liquid to starch is 2.5:1,the maximum adsorption capacity is reached,and the survival rate after freeze-drying is 41.08%.The formulation of the freeze-dried protective agent was optimized,and the best freeze-dried protective agent was finally determined to be lactose 11%,mannitol 2.6%,sodium thiosulfate0.013%,the survival rate reached 92.43±1.43%,and the spore rate could reach 68.79±2.15%.Then use sodium alginate and CaCl₂ for embedding to obtain a solid inoculum.（4）Study on the aerobic composting effect of solid microbial inoculants.The prepared solid inoculum was subjected to compost verification,and the results showed that the prepared solid inoculum could still maintain good stability after three months.The composting effect showed that compared with the blank,the degradation rate of organic matter increased by20.44%.Compared with CK,the content of humus increased by 3.44%.The resulting compost product has a relatively high degree of maturity,with a GI value of 103.41%and a biological toxicity index that meets the maturity standard,and the antibiotic removal rate is 100%.And the addition of solid bacteria agents promoted the degradation of antibiotics during the high temperature period.