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Polycyclic Aromatic Hydrocarbons (PAHs) pollution on the ammonia -oxidizing bacteria and microbial community structure of

Author: LiuJie
Tutor: PengXiaZuo
School: Beijing Forestry University
Course: Microbiology
Keywords: Microbial oxidation of ammonia PAHs Soil Ammonia oxidation potential Quantitative PCR
CLC: X703
Type: Master's thesis
Year: 2011
Downloads: 137
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Abstract

Nitrification of ammonia oxidation is the first reaction step is rate-limiting step is the central link in the global nitrogen cycle. Ammonia oxidizing bacteria and ammonia oxidizing archaea composition, quantity, and ecological characteristics of the knowledge, understanding of the global nitrogen cycle will improve nitrogen use efficiency, reduce nitrogen to provide an important basis for environmental hazards. The first experiments using simulated PAHs contaminated artificially added pyrene way to study the number of soil microbial communities, ammonia-oxidizing microbial community structure and activity indicators PNR and pyrene dose - response relationship; then long PAHs contaminated soil samples for the coking plant object of study, measurement and analysis of ammonia oxidation and microbial species variable relationships between environmental variables, in order from the study found the law to clarify the relevant factors, particularly PAHs microbial oxidation of ammonia and ammonia oxidation process. PAHs contaminated artificially added pyrene simulation experiment 1) the number of culturable microorganisms: actinomycetes last significantly affected; bacteria with increasing concentrations of pyrene and the growth of the processing time showed a decreasing trend; fungi in pyrene concentration 40μg / g, a weak decrease in the concentration of pyrene 100μg / g relative to the blank control Shique a significant increase. 2) Soil PLFA analysis: pyrene in soil treated with low concentrations of PLFA were demonstrated with the processing time of the decline in the growth and inhibition with increasing concentration of pyrene become strong; while high concentrations of pyrene in soil PLFA has remained at a low level, the inhibition rate was about 75 percent. Principal component analysis revealed that the microbial community structure changes with PLFA abundance data correspond. 3) moderate concentrations of pyrene significant impact on the PNR, the first 1,7,15,35-day EC50 values ??were 72.2μg / g, 73.4μg / g, 99.57μg / g, 101.8μg / g, showed moderate concentrations of pyrene can seriously affect the activity of microbial oxidation of ammonia, and the EC50 is the extension of the treatment time increases. The high concentration of pyrene soil can exhibit acute toxicity, low concentration obvious acute toxicity of pyrene; pyrene chronic effects of PNR After 7 days of treatment at immediately after manifested, after 15 days or more processing can be achieved steady state, and chronic toxic effects of pyrene pyrene concentrations with increasing strengthened. 4) qAOA higher than qAOB about an order of magnitude, but in the conditions of this study add pyrene does not significantly alter the ammonia-oxidizing microbial community abundance, that PAHs may be used as short-term AMO competitive or non-competitive inhibitor for PNR impact. Comprehensive analysis of the above findings, the PNR right Ⅰ PAHs soil response is more sensitive and can serve as an indicator reflecting the sublethal effects of toxic PAHs, in conjunction with other indicators of changes in the presence of soil biological consistency and reflects the resistance of PAHs or adaptive, so that the PNR PAHs in soil toxicity study has unique advantages, but it is necessary to combine the analysis of long-term improvement of soil PAHs related research. Beijing Coking Plant long PAHs contaminated soil samples in Experiment 1) ammonia oxidation microbial species environment variables and the relationship between the variables of soil factors: soil pH and soil PNR have a weak positive correlation, SMC PNR no correlation with the soil. SMC and pH on qAOB no significant correlation, SMC negatively correlated with qAOA, pH, and qAOA significant positive correlation. PNR and NH4, NO2-and NO3-relations, notably the reaction of species data on environmental factors, namely soil PNR right NH4 NO2-and NO3-in. 2) ammonia oxidation microbial species relationship between the variables: the majority of sampling points qAOA than qAOB about 1-3 orders of magnitude higher, but found high concentrations of PAHs in the soil can make qAOB microenvironment than qAOA. qAOA, qAOB relationship with soil PNR curves correspond Logarithm dual parametric curves and qAOB with PNR curve fitting (R = 0.59; P lt; 0.05) than qAOA with PNR curve fitting (R = 0.35; P gt; 0.05 ) have a more significant correlation, indicating that the soil PNR greater impact by the AOB. 3) PAHs residual soil between PNR: Low concentrations of PAHs (to 75μg / g for the line) the impact on soil PNR effect on soil with high concentrations of PAHs PNR impact effect is different modes; soils PNR In PAHs lt; 75μg / g of the soil environment, with the increase of PAHs. And PAHs with qAOA and (?) QAOB positive correlation exists between. In PAHs gt; 75μg / g of soil environment, most PAHs with PNR no correlation, a few such as naphthalene and PNR showed a weak positive correlation, acenaphthylene, fluorene, phenanthrene it with PNR showed negative correlation .

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