Study On Abundance,diversity And Community Structure Of Bacteria In Penicillin Fermentation Fungi Residue Composting

Antibiotic fermentation fungi residue(AFFR)has been managed in accordance with the hazardous waste in the case of the small amount of antibiotics and the related metabolite remaining.The thermophilic aerobic composting is an effective way of disposing the AFFR with advantages in convenience,economical and environmental.The loss of nitrogen is universal phenomenon,and ammonia oxidation is also an important step in nitrogen cycle.Therefore,the study of ammonia oxidation is the basis of controlling nitrogen loss.It is a hotspot to study on maturity evaluation,antibiotic degradation and microbial community structure in the AFFR-composting,which can be guidance for a AFFR composting product quality and application.However,many studies of AFFR composting mainly focused on microbial activity,abundance and antibiotic resistance genes(ARGs).Therefore,molecular techniques such as QPCR,PCR-DGGE and high-throughput sequencing were used to analyze the penicillin fermentation fungi residue(PFFR)co-composting in this study.Four piles(manure-wet PFFR,manure-dried PFFR,manure-penicillin,pure manure composting)were seted to analyze the process of the maturity,nitrogen cycling and the abundance,diversity and community structure of the bacteria,ammonia-oxidizing bacteria(AOB)and ammonia-oxidizing archaea(AOA).The results are as follows:After the 30-day high-temperature aerobic composting process,the dynamic changes of physic-chemical indexes such as temperature,moisture,pH,EI,C/N ratio and germination index(GI)were important to evaluate compost maturity.4 piles all gone through the mesophilic,thermophilic and maturing stages.The water lossing mainly occurred in the thermophilic period,and the content was between 29.8%-36.5%.At the end of composting the pH values were among 7.4-7.9,EC values were among 5.5-4.1ms/cm,the C/N ratio was among 17.6 and 20.3:GI increased to 119.7%-139.3%.Ammonium nitrogen in 4 piles were 2.7g/kg,1.6g/kg,1.5g/kg and 0.9g/kg.Nitrate nitrogen increased by 88.2mg/kg、319.8mg/kg、101.7 mg/kg、131.9 mg/kg.The results of physic-chemical and biological parameters of four composting piles have indicated that composting reached maturity.Thermophilic composting can rapidly degrade penicillin residues.The penicillin in manure-wet penicillin mycelial dreg and manure-penicillin composting was decreased lower than detection line of UPLC in 9 days and 2 days.Penicillin in manure-dried penicillin mycelial dreg,and pure pig manure composting was not detected.The diversity and community succession of bacteria in manure-wet PFFR,and pure pig manure composting were studied by high-throughput sequencing technique.Except day 25,The Chaol estimators of manure-wet PFFR,compost were higher than that of pure pig manure composting.And the Shannon index of manure-wet PFFR,compost was always higher than that of pure pig manure composting.Canonical correspondence analysis(CCA)was performed to verify if there was a relationship between bacterial community shifts in the samples with the different physic-chemical parameters.The results showed that the addition of PFFR changed the structure and distribution of bacterial in composting,and the difference of species composition gradually increased with the progress of composting.The water content and germination index significantly affected the change of community structure.At the mesophilic stage(0d)the class Gammaproteobacteria,Clostridia and Bacilli,the genus Pseudomonas,Coprococcus,Bacillus were dominant.In the thermophilic stage(9d)class Bacteroidia and Clostridia were dominant;the most abundant genus,Clostridium,Leptonema,Sphaerisporangium.At maturing stage(30d),the highest abundance class was Clostridia,Bacteroidia and Gammaproteobacteria;the highest abundance genus was Clostridium.Dominant bacteria vary with the different stages and raw material in composting.QPCR technique was used to analyze the dynamic changes of ammonia-oxidizing bacteria abundance in composting,the result shown that ammonia-oxidizing bacteria and ammonia-oxidizing bacteria in different composting systems were alternately becoming dominant populations in different composting stages.And it shown that ammonia oxidation played an important role in the oxidation of ammonia nitrogen in the different temperature stages of composting.There was a significant negative correlation between between AOB amoA gene abundance and C/N ratio nitrate nitrogen concentration.There was a significant positive correlation between AOA amoA gene abundance and ammonium nitrogen.In the PCR-DGGE fingerprints,the AOB amoA gene sequences were Nitrosospira and Nitrosomonas,Nitrosomonas was the dominant species.The sequencing results showed that AOA amoA gene in composting were highly simila with AOA amoA gene in the sediments of the deep sea sediments and the surface sediments.