Diversity Of Ammonia Oxidating Bacteria (AOB)and Ammonia Oxidating Archae (AOA) Duirng The Process Of Composting

Ammonium oxidation bacteria (AOB) and ammonia oxidizing archaea (AOA) play an important role inthe process of nitrogen cycling in nature. In recent years, research about the diversity of AOB and AOA in thecomposting process and their functional mechanism has become a hotspot in the international research field. Inorder to reveal the role of AOB and AOA in ammonium oxidation process during the composting process, weused cow-dung as the main feedstock, the grass and the rice chaff as the amendments, the volume ratio of thesematerials was5:4:1, then blend well, the static composting experiment were carried out under the outdoorconditions. Using molecular cloning technology, PCR-DGGE, QPCR technology to study the diversity and therelative quantity of the AOB and AOA in the turning treatments, control group (do not need to turning thecompost), turning treatments that added ammonium nitrogen, sampling at4d (warming period),10d(megathermal period),30d (cooling period) and60d (rotten period), the results of our study were showed asfollows:1. In order to amplify the functional gene fragment in the ammonium oxidation flora from the compostingenvironment, PCR were performed, used amoA specific function genes primers. The functional genes of AOBand AOA were amplified, the functional gene fragment of AOA was610bp and the functional gene fragment ofAOB was490bp.2. We had established the clone library of AOA and AOB in the warming period, megathermal period,cooling period and the rotten period, and the results indicated that, functional genes of AOA only emerged atthe rotten period. For the clone library of AOB in different period, as the nucleic acid sequencing resultsrevealed, AOB in the compost were Nitrosomonas and Nitrosospira.3. Used the DGGE technology to investigate the variation tendency of the AOB in the four period of thecompost, the result showed that, the AOB changes with the temperature, the diversity of the AOB were amplein the warming period, appeared8bands, then decreased in the megathermal period (only4bands), andabundant in the cooling period (9bands), there were8bands in the rotten period. As the temperature of thecompost system was closed to the environment temperature, the diversity of the AOB was tending towardsstability, and all the AOB strains were Nitrosomonas.4. The results of this study show that, the numbers of ammonium oxidation bacteria variety in differentperiod. In different period of the turning treatments, control group, turning treatments that added ammoniumnitrogen, the number of ammonium oxidation bacteria was highest in the megathermal period, which were9.2x105,5.8x1052.0x106a/μlDNA respectively. The lowest number of ammonium oxidation bacteria wereappeared in the warming period, which were2.3x105,1.1x105,9.0x105/μlDNA. The number of AOB inturning treatments were significantly larger than the control groups, analysis results about the numbers of AOBin different period and the physical and chemical parameters of the compost indicated that, the temperature ofthe compost, ammonia nitrogen and nitrate nitrogen could significant affected the number of AOB, theinfluence of the first two factors could reached a extremely significant level. The effective control of theseparameters could be very important, which would regulation the activity of ammonium oxidation bacterial inthe agricultural waste composting.