[Characteristics and Mechanism of Biological Nitrogen and Phosphorus Removal Granular Sludge Under Carbon Source Stress].

In SBR reactor, the mature granular sludge fed with sodium acetate was gradually cultivated with different carbon sources (sodium acetate/glucose ratio was 1:0, 3:1, 1:1, 1:3 and 0:1, in terms of COD, respectively). During the five stages, the physical, biochemical properties, extracellular polymeric substances (EPS), phosphorus fractions and nitrogen and phosphorus removal efficiency of granular sludge were studied. 705 days' experimental results were showed as follows.

[Development and succession of biological soil crusts and the changes of microbial biomasses].

Biological soil crusts (BSCs) play important ecological roles in vegetation and ecological restoration in desert regions, and different crust developmental and successional stages have different ecological functions. In this experiment, the BSCs in Shapotou region (at southeast edge of Tengger Desert) were investigated to study crust development and succession through field investigation, microscopic observation combined with quantitative analysis of microbial biomasses. The results showed that BSCs in this region generally developed and succeeded from algal crusts, lichen crusts to moss crusts.

[Development and succession of artificial biological soil crusts and water holding characteristics of topsoil].

In order to understand the improving effects of cyanobacterial inoculation on water retention of topsoil in desert regions, this work focused on the development and succession of biological soil crusts and water holding characteristics of topsoil after cyanobacterial inoculation in Qubqi Desert. The results showed that after the artificial inoculation of desert cyanobacteria, algal crusts were quickly formed, and in some microenvironments direct succession of the algal crusts to moss crusts occurred after 2-3 years. With the development and succession of biological soil crusts, the topsoil biomass, polysaccharides content, crust thickness and porosity increased, while the soil bulk density decreased.

[Isolation, identification and characterization of a microcystin-degrading bacterium Paucibacter sp. strain CH].

A bacterium capable of degrading microcystin (MC), strain CH, was isolated from the sediment of Lake Chaohu, China. Strain CH was tentatively identified as Paucibacter sp. based on the analysis of 16S rRNA gene sequences.

[Anaerobic biodegradation of microcystin by bacterial community from sediment of Dianchi Lake].

Aerobic biodegradation has been identified as the main attenuation mechanism for microcystin, but the role of anaerobic microcystin biodegradation remains unclear. To elucidate this process, we assessed the potential for anaerobic microcystin LR biodegradation by sediment microbial community from Dianchi Lake and evaluated the effects of environmental factors and additional nutrient sources on the rates of anaerobic biodegradation. The results showed that microcystin LR was rapidly degraded from 5 mg/L to below detection limit within 2 days, demonstrating that the indigenous microorganisms can efficiently degrade microcystin LR under anaerobic conditions and can use microcystin LR as a sole nitrogen source.

[Subchronic toxic effects of fish muscle-bound MCLR].

Subchronic oral gavage toxicity of MCLR in water and in fish muscle was examined in male Balb/C mice for 13 weeks to assess the safety of aquatic products. The results showed that the liver coefficient (p < 0.05), the activities of ALT and AST (p < 0.

[Preparative purification and characterization of [Dha7] microcystin RR].

One variant of microcystins was isolated and purified with cyanobacteria natural bloom as the starting material, which was collected in Dianchi Lake, China. The separation protocol involved extraction of cyanobacterial cells by 75% aqueous methanol, isolation by reversed-phase flash chromatography, and purification by reversed-phase semipreparative HPLC. The structure and purity of purified microcystin was identified with electrospray ionization mass spectrometry, UV spectrophotometer, and analytical HPLC.

[Chemical characteristics of nitrogen and phosphorus in the sediments of the typical bays in Dianchi Lake and calculation of their dredging layers].

The sediments of Haidong bay and Macun bay in Dianchi Lakes' experimental area were studied. The sediment column was cut in every 3cm, and the following items are tested, such as total phosphorus, phosphorus species, which include labile phosphate, Fe,Al-P, Ca-P and residual-P, total nitrogen, nitrate nitrogen, nitrite nitrogen, ammonium nitrogen. The results showed that the loads of nitrogen and phosphorus of these two bays increased quickly in recent years.