Study Of Maturity Assessment And Influence Of Distribution Of Penicillin Resistance Geges (Prgs) During The Thermophilic Composting Of Penicillin Bacteria Residue

China has become the largest antibiotic manufacture country, penicillin, for example, its production and usage in China always occupy the first place. The penicillin bacteria residue has been seemed as a kind of recyclable resource for which contains rich high-quality protein. However, penicillin bacteria residue contains small amount of antibiotics and the degradation produces during the manufacturing process. So, Penicillin bacteria residue is one of the hazardous wastes now. It will be able to develop and spread the resistant bacteria and resistance genes due to the improper disposal. In this research, an aerobic co-composting system was used to treat penicillin bacteria residue mixed with pig manure in order to eliminate the penicillin residue and valuate the effect of β-lactamase genotype flora changes during the co-compost process.Composts with different ratio of penicillin bacteria residue, pig manure and sawdust were carried out in the reseach. The whole composting process was 30ds and completed in Vegetable Science and Technology Institute in Nanjing, Jiangsu province. Three treatments were designed by adding different proportion of pig manure and penicillin bactaria residue,1:1,2:1,4:1, respectively. The composting of pig manure without penicillin bactaria residue was used as control. The influence of different penicillin bacteria residue proportion on compost maturity through physic, chemistry and biology index was detected. The abundance and distribution of eight reported β-lactamases genes (bla_-TEM, bla_-CTX-M-1, bla_-CTX-M-9, bla_-IMP-1, bla_-VIM-2, bla_-NDM-1,bla_-CMY and bla_-OXA-23) were determined by quantitative PCR （qPCR）, Isolation and analyzing penicillin-degrading bacteria. The main results are as follows:The results of physic-chemistry and biology index shows that the all group of compost had been rotted after 30ds, and the treatment with adding penicillin bacteria residue own more longer in the thermophilic phases. The compost temperature closed to room temperature, the color changed from yellowish to dark brown, the materials became loose and eventually the compost odor and flies around disappeared in the end of composting process. pH of different groups were 7.3,7.4,7.3,7.9 and EC values were 6.3,5.5,5.3 and 4.3ms/cm. Organic and total nitrogen content showed a downward trend, at the end of the experiment, four treatments of organic carbon content were decreased by 14.1%,19.7%,17.7% and 27.1%, total nitrogen content were decreased by 27.4%,14.0%,4.4% and 16.5%. The seed germination rate increased to over 80% which reached the standard of non plant toxicity.Penicillin residue wasrapidly removed in the compost piles from the initial （305.1±16.8） mg/kg, （208.6±4.2） mg/kg and （74.9±3.0） mg/kg to below the UPLC method detection limit. Penicillin degradation with treatment groups fit with first-order reaction kinetics model, the rate constant （k） for different groups were 0.3d-1,0.2d-1 and 0.2d-1,the degradation half-life （t1/2） were 1.9d,2.4d and 2.3d, respectively. The half-life greatly shorter than that at room temperature （25℃） 39.4d.The quantification of eight β-lactamases genes was decreased during aerobic co-composting. In the end of 4 composting processes, the copy number of bla₍-TEM gene decreased by 69.4%,53.3%,67.9% and 51.7%, respectively. The copy number of bla_-CTX-M-1 gene decreased by 93.4%,98.8%,98.9% and 84.6%, respectively. The copy number of bla_-CTX-M-9 gene decreased by 99.0%,99.9%,99.9% and 99.7%, respectively. bla_-IMP-1 copy number decreased by 99.8% and 72.6% in treatment 3 and control, but increased up to 21.8 and 16.3 times compared to the initial value in treatment 1 and 2. The copies of bla_-VIM also increased to 0.7 and 4.0 times during treatment 1 and 3, but decreased by 99.8% and 78.3% during during treatment 2 and control, respectively. The copies of bla_-CMY gene showed a trend of decline in treatments and decreased by 80.5%,43.6% and 88.3%, respectively. It was undetectable for bla_-oxA-23 during treatment 1 and 2 and decreased as much as 80.2% and 74.3% in treatment 3 and control. During four composting processes,bla_-NDM-1 was not detected.A penicillin-degrading strain PC-2^T was isolated and purified from the treatment groups. It was identified as Chelatococcus sp. via 16S rDNA gene based phylogenetic analysis and morphological observation. PC-2^T was gram negative bacteria by gram staining observation. The PC-2^T colony on LB plate was round, milky white, smooth, convex, opaque, neat edge and its diameter was about 1-2mm. Under scanning electron microscope, PC-2^T was short rod and its width was about 0.8-1.0μm, length was 1.8-2.8μm. The main fatty acid content of PC-2^T were C18:1 w7c （50.7%） and C19:0 cyclo w8c （22.3%） and the G+C mol% was 70.9mol%. As high as 98% of penicillin was degraded by PC-2^T after 6h incubation under the optimal conditions of 37℃,14% inoculuun size, pH 6-8 and 150r/min, when the initial penicillin concentration was 400 mg/L and glucose and peptone were added as carbon and nitrogen sources, respectively.The penicillin bacteria residue compost could be considered mature 30 days later based on all the physico-chemical and biological indices. The quantification of β-lactamases genes in this research decreased during aerobic co-composting. However, more research need to explain the abundance and distribution of β-lactamases genes and their horizontal transfer in pathogenic microorganisms during penicillin bacteria residue composting process.