[Mechanism and Application of Plant Growth-Promoting Bacteria in Heavy Metal Bioremediation].

Heavy metal contamination is one of the main factors causing ecological and environmental degradation. Soil contamination by heavy metals decreases soil quality, reduces agricultural productivity and quality, and even threatens human health. Therefore, optimizing remediation strategies for soils polluted with heavy metals is of great significance for high-yield, good-quality, and sustainable agriculture.

[Identification and Characterization of a Hypothermic Alkaliphilic Aerobic Denitrifying Bacterium Strain H97].

Low temperatures and high pH generally inhibit bio-denitrification. Thus, it is important to explore psychrotrophic and alkali-resistant microorganisms for nitrogen degradation. This study mainly focused on the identification of an alkaliphilic strain and preliminary exploration of its denitrification characteristics.

[Effects of PAHs Pollution on the Community Structure of Denitrifiers in a Typical Oilfield].

Agricultural soils in the oilfields have the potential risk of PAHs (polycyclic aromatic hydrocarbons) pollution, and the denitrification process with nitrate as the terminal electron acceptor might be important for soil PAHs elimination under anaerobic condition. In this study, 9 soil samples listed as JH-1 to JH-9 were collected from the JiangHan oilfield with a history of more than 50 years. Using the functional genes (-nitrite reductase gene; -nitrite reductase gene) involved in denitrification as biomarkers, the community structure of soil denitrifiers was investigated by quantitative-PCR and T-RFLP (terminal-restriction fragment length polymorphism) combined with clone library, and the relationship between soil properties and community structure of soil denitrifers was discussed.

[Efficiency and Mechanism of Capping with Purple Parent Rocks to Control Phosphorus Release from Sediments].

In order to study the efficiency and mechanism of capping with purple parent rocks to control phosphorus release from sediments, three kinds of purple parent rocks (Fei-xian-guan Formation, Peng-lai-zhen Formation and Sui-ning Formation) which distribute widely in Chongqing, and two types of rock (limestone and calcite) which have been found to effectively control the release of phosphorus from sediments, were selected as active covering materials to cap the sediments to conduct simulation experiment. The results indicated that: all three kinds of purple parent rocks showed strong inhibition of total phosphorus release from sediments to the overlying water, far better than limestone and calcite (<0.05), and the highest removal rate of total phosphorus was 94.

[Heterotrophic Nitrification and Aerobic Denitrification of the Hypothermia Aerobic Denitrification Bacterium: Arthrobacter arilaitensis].

High concentrations of ammonium, nitrate and nitrite nitrogen were employed to clarify the abilities of heterotrophic nitrification and aerobic denitrification of Arthrobacter arilaitensis strain Y-10. Meanwhile, by means of inoculating the strain suspension into the mixed ammonium and nitrate, ammonium and nitrite nitrogen simulated wastewater, we studied the simultaneous nitrification and denitrification ability of Arthrobacter arilaitensis strain Y-10. In addition, cell optical density was assayed in each nitrogen removal process to analyze the relationship of cell growth and nitrogen removal efficiency.

[Isolation, Identification and Characteristics of a with High Ammonia-nitrogen Removal Efficiency].

A strain of photosynthetic bacterium named psb1 capable of ammonia-nitrogen degradation was isolated from a swamp in Yunnan. The psb1 was similar to sp. according to its cell morphological properties and absorption spectrum analysis of living cells.

[Effect of Different Purple Parent Rock on Removal Rates of Nitrogen, Phosphorus and Organics in Landscape Water].

In order to understand the impacts of physicochemical properties of purple parent rock on the removal rates of nitrogen, phosphorus and organics in landscape water systems, four types of purple parent rocks including Peng-lai-zhen Formation (S1) , Sha-xi-miao Formation (S2) , Fei-xian-guan Formation (S3) and Sui-ning Formation (S4) , which distribute widely in Chongqing, were selected and autoclaved, and added to unsterile landscape water collected from Chong-de Lake in Southwest University, and the landscape water only was used as control. And several indicators such as total nitrogen and phosphorus and so on of every disposal were investigated periodically. The results indicated that: (1) The highest removal rates of total nitrogen, total phosphorus and Ammonia nitrogen were observed in Sl, which were 45.