Advances in bioremediation of polycyclic aromatic hydrocarbons contaminated soil / 生物工程学报

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent pollutants that are widely distributed in the environment. Due to their stable structure and poor degradability, PAHs exhibit carcinogenic, teratogenic, and mutagenic toxicity to the ecological environment and organisms, thus increasing attentions have been paid to their removals and remediation. Green, safe and economical technologies are widely used in the bioremediation of PAHs-contaminated soil. This article summarizes the present status of PAHs pollution in soil of China from the aspects of origin, migration, fate, and pollution level. Meanwhile, the types of microorganisms and plants capable of degrading PAHs, as well as the underlying mechanisms, are summarized. The features of three major bioremediation technologies, i.e., microbial remediation, phytoremediation, and joint remediation, are compared. Analysis of the interaction mechanisms between plants and microorganisms, selection and cultivation of stress-resistant strains and plants, as well as safety and efficacy evaluation of practical applications, are expected to become future directions in this field.

Development of bioremediation in China--a review / 生物工程学报

The development of bioremediation for contaminated soil in China during past 30 years was briefly reviewed, mainly including the developing stages, bioremediation techniques/strategies and their applications, and isolation, screening and characterizations of microbial strains for bioremediation as well as their efficiencies in bioremediation of contaminated soils. Finally, future development of bioremediation techniques/strategies and their applications were also discussed.

THE SCREEN AND CHARACTERIZATION OF A FLOCCULANT-PRODUCING BACTERIUM / 微生物学通报

Abacterial strain A25, isolated from activated sludge and identified as Bacillius megaterium, could produce flocculant, The optimum carbon and nitrogen sources are maltose and yeast extract, respectively. The optimum pH range is 7.0～10.0. The flocculant was synthesized during the cell growth. The flocculant mainly exists in the supermatant. The partial purified flocculant could be kept in 60C for 1 hour without losing activity.

A STUDY ON DECOLORIZATION OF DYES BY CELLS IMMOBILIZED IN BI-CARRIERS / 微生物学通报

Spreaded and immobilized the bacterial cells entraped in PVA on pieces of cotton cloth as porous carrier. The conditions for preparing immobilized cells were as below: cell concentration, 20 mg wet weight/ml; PVA concentration, 5%; spreading amount, 0.3ml/cm~2; immobilization for 12 hours in saturated boron acid solution. Then activated the immobilized cells in buffer containing dyes. Thus, immobilized cells with high decolorizing activity were obtained.In columns packed with immobilized cells, the decolorization efficiencies of continuous influent and intermissional influent were compared with each other. In twenty days, the decolorization rates were both higher than 90%; then the decolorization rate of continuous influent decreased to about 60% after 60 days while it still reached 80% in case of intermissional influent. The efficiency of the later was distinct higher than that of the former.