Abstract:A low-temperature hydrocarbon-degrading strain T7-2, isolated from sea-mud of Bohai polluted area and identified as Rhodococcus erythropolis, was found to produce an extracellular, nondialyzable emulsifying agent (referred to as bioemulsifier) when grew with hexadecane as carbon source. The results showed that, this bioemulsifier which could remarkably emulsify hydrocarbons such as diesel oil, is consisted of three parts-carbohydrates, lipids and proteins, the proportion of which was 55.43:31.24:12.65. The monosaccharide compositions were identified as mannose and rhamnose; the lipid compositions included decanoic acid, lauric acid, hexadecanoic acid and stearic acid, and the protein constituents were composed of sixteen amino acids. Besides, according to the study of the physic-chemical properties of the bioemulsifier, it possesses the obvious advantages of character stability, high function efficiency and wide adaptation range, therefore this bioemulsifier is believed to have extensive application values for bioremediation of marine oil pollution, petroleum exploitation and etc.

Abstract:Three-dimensional structure model of azoreductase AZR of Rhodobacter sphaeroides was constructed using homology modeling method. It is a flavodoxin adopting a/b structure. Structure alignment of two different types of flavin-dependent azoreductases revealed that they possessed high similarity. Based on sequence and structure analysis, site-directed mutagenesis of K109H and K109A were performed. The optimal pH values are pH 6 and pH 9 for K109H and K109A mutant protein, respectively. The optimal temperature (30℃) is not affected by mutagenesis. Positively charged residues at position 109 is necessary for the binding of methyl red, while K109H is not a conserved mutagenesis for the binding of NADPH. K109 may only be involved in the binding of the 2’-phosphate group of NADPH and have no effect on the binding of NADH.

Abstract:The influences of several factors on the growth and removal for 1,2-Dichlorobenzene of Rhodobacter sphaeroidcs under phototrophic (anaerobic in light) condition were analyzed in this study. The results demonstrated that the optimum conditions for the growth of the strain and the removal rate for 1,2-Dichlorobenzene were pH 7.0, temperature at 30℃ and inoculation amount of 10% under phototrophic condition．The removal rate for 1,2-Dichlorobenzene reached 90%under the optimal conditions．Furthermore, analysis of degradation products of 1,2-dichlorobenzene by the strain tested showed that chlorobenzene, 4-hydroxybenzote were formed. The probable degradative routs taken in the anaerobic metabolism of chlorinated aromatic compounds by Rhodobacter sphaeroides were that they are metabolized anaerobically to form chlorobenzene, and then chlorobenzene was dechlorinated and passed through 4-hydroxybenzote routes for aromatic ring cleavage.

Abstract:This research is to optimise the best nutrition condition of the phytase-producing strain (Spicaria Harting 26-13-4) which is from the black soil growing soy bean in Hailun City, Heilongjiang Province. The D-saturation and optimization design are carried out on the added amount of carbon, nitrogen and bran on the ferment substrate. The equation is made according to the three material then the best added amount can be confirmed.

Abstract:Four strains of aerobic denitrifying bacteria were isolated from biomembrane of the laboratory biofilter by selective medium. The denitrifying rates of these four strains were found more than 80% under aerobic condition for 40 hours. The denitrifying rate of A1 was highest, which was 99.05%. When measuring the course of nitrogen element changing, it is found that they accumulated nitrite expect the strain A1. The strain A1 was gram positive and spherical. It is identified as Pseudomonas putida based on its biochemical and morphological characters and phylogenetic analysis of 16S rDNA sequences(genbank accession NO.DQ836052.1). For the strain A1, the optimum beginning pH was 7.0 around, and the optimum temperature was 30℃ around, The change of DO did not influence the effect of denitrification when it was more than 2.0 mg/L.

Abstract:The stability of microbial flocculant (MBF) produced by Aspergillus sojae and its application to municipal thickened sludge dewatering were studied. The results showed that the MBF had high heat and acid-base endurance with high flocculating activity in a wide range of pH from 1.5 to 12. The MBF retained 96% of flocculating activity after 35 days preservation at 4℃, but in different pH the flocculating activity difference was very apparent after 35 days store at room temperature. The experimental results also demonstrated that the MBF was better than PAM and PAC in reducing specific resistance filtration. The optimal dose of MBF used for intensifying thickened sludge dewatering is 7%(volume fraction). And the more the volume of sludge is treated, the less the cost of MBF for unit volume sludge treatment.

Abstract:Four screening methods, colorimetric assay, blood-plate hemolysis method, surface tension activity and oil spreading technique were introduced to isolate strains producing bio-demulsifiers from 6 different bacteria source samples. The results of various screening methods were evaluated in this paper. Seventeen demulsifying strains were obtained, which are qualified in demulsification test of kerosene model emulsions. Among them, 5 strains showed high demulsifying ability, achieving 70% plus demulsifying ratio within 24 hours. Petroleum-contaminated soil, excess sludge from biological process treating oilfield produced water and sludge from municipal wastewater treatment plant were the best among all tested sources. Due to the determination limit, the colorimetric assay and blood-plate hemolysis method are not competent to screen bio-demulsifiers strains. The measurement of surface tension and oil spreading method were easy but accurate methods to isolate bio-demulsifiers strains. Although demulsification test of model emulsion is an effective technique to target strains with the capability of breaking emulsions, it is sophisticated and time-con- suming. Thus it is recommended to use surface tension and oil spreading methods in pre-screening and validate the results in demulsification test with kerosene model emulsions.

Abstract:A bacterium strain D-1 capable of degrading DDT was isolated from the DDT contaminated soil．Based on the phenotype, physiological and biochemical characteristics, and the phylogenetic analysis of 16S rDNA sequence, the strain D-1 was identified preliminarily as Stenotrophomonas sp.. This strain could degrade DDT under condition of 30℃, pH7.0, 200 r/min, with degradation efficiency of 69.0% in 10 days.

Abstract:The aerolysin genes (aerA) of BZ and NK isolates were cloned and sequenced. The sequence analysis showed that the partial aerA of BZ and NK isolates consisted of 1393 bp, encoding a protein of 464 amino acids. The similarity of nucleotide and amino acid sequences of aerA between BZ and NK isolates was 97.6% and 98.3% respectively. The nucleotide sequence of aerA of BZ strain exhibited 71.6% to 97.5% homology with other Aeromonas isolates, and the amino acid sequence exhibited 68.0% to 98.9% homology. The phylogenetic tree based on aerA nucleotide sequences from Aeromonas isolates was constructed with neighbor-joining method. It showed that there were three branches of aerolysin genes, and a close relationship among Aeromonas hydrophila isolates which were clustered into the same branch.

Abstract:A bacterium, having high chitinolytic activity, was isolated from sediment of Shantou Bay, named SWCH-6. According to its physiological and biochemical characteristics and 16S rDNA sequence, it was identified as Aeromonas hydrophlilla. The optimal chitinase fermentation conditions of strain SWCH-6 were conformed by single-factor experiments and orthogonal experiments, they were colloidal chitin 25.0 g/L, tryptone 10.0 g/L, seawater 1 L, pH 8.5, 32℃, 150 r/min for 72 h. In these conditions, its chitinase activity reached 0.39 U/mL. In addition, at 40℃and pH 5.0, its chitinase performed the highest catalytic activity and its chitinase activity could be enhanced by Cu2+, Fe3+ and surfactant toween-80; weakened by Zn2+, Mn2+ and surfactants SDS, detergent powder, and there were some differences from orther chitinases.

Abstract:Strain NCIMB 10467, a lignin degrader, was reclassified as genus Burkholderia according to its 16S rDNA sequence. It seems that the metabolism of protocatechuate by this strain is diverse under the induction of various substrates. A 9505-bp DNA fragment extending from a conserved region of the gene, which encodes a subunit of ortho cleavage protocatechuate 3,4-dioxygenase (P34D; EC 1.13.11.3), was obtained by genome walking. Sequence analysis revealed two deduced open reading frames, pcaG and pcaH, encoding the a and b subunits of P34D respectively in this fragment. The P34D activity could be detected when pcaGH were expressed in E. coli and the disruption of pcaH in strain NCIMB 10467 has lead to loss of its ability to catabolize protocatechuate. It was proved that the cloned pcaGH were encoding a functional protocatechuate 3,4-dioxygenase which was necessary for the protocatechuate metabolism in this strain.

Abstract:In order to determine the degradation activity of the microbial community NSC-7, which had efficient cellulose and lindan degrading ability, degrading ability and four kinds of cellulase activity and hemicellulase activity were detected during degradation progress. The results showed that NSC-7 could degrade 73.6% of rice staw in weight, including 82.1% of cellulose, 58.2% of hemicellulase, and 5.4% of lignin within fourteen days. Endoglucanases, exoglucanases, β-glucosidases and the total cellulase activities reached to maximum at the eighth day, and they were 4.48 U/mL, 15.83 U/mL, 25.78 U/mL and 7.51U /mL, respectively. The maximum of hemicellulase activity was 280.6 U/mL at the fifth day, and the average of hemicellulase activity was 43.71 times higher than cellulase activity.

Abstract:The cultural characteristics and stability of the bacteria community NSC-7, which was capable of degrading cellulose and lindane with high efficiency was discussed in this study. NSC-7 could degrade 73.6% of rice straw within 14 d. 10 kinds of material were detected in volatile products by gas chromatography mass spectrometry (GC-MS), and they were mainly acetic acid, glycerol, butyric acid, and propanoic acid. NSC-7 could retain stable degrading ability and high cellulase activity after preserved in -80℃ and freeze-drying for four years. It could remain its degrading ability after 90℃ of high temperature treating for 30 min, and resume its degrading ability after subcultured 2 times after 105℃ of high temperature treating for 30 min in autoclave. It suggested that NSC-7 had efficient conservation stability and thermo-stability. DGGE analysis showed that the composition of NSC-7 remained stable after subcultured for several times.

Abstract:In order to analyze the bacterial population diversity in surface layer(10 cm depth) of CRI, a bacterial 16S rDNA gene clone library was constructed. The results indicated that the bacterial community composition in surface Layer of CRI was high diversity and could be divided into 7 groups. The uncultured Acidobacteria and uncultured bacteria were the largest fraction(53.72% of total clones), followed by uncultured planctomycete (13.89%) and β-proteobacterium (8.33%); In clone library, the proportion of denitrifying bacteria was larger than that of nitrosobacteria and Nitrospira-like bacteria wasn’t found. The high percentage of uncultured bacterial clones predominated in clone library, but by plating culture method the majority colonies were only Pseudomonas aeroginosa and Chromobacterium sp., Which were the minority presented in clone library. The results demonstrated that either the bacterial community composition diversity or the abundance of phytogenetic groups analyzed by 16S rDNA clone library were much higher than those by plating culture method. The bacterial population diversity shown by 16S rDNA gene library is certain meaningful to reveal the activity profile of biodegradation in CRI.

Abstract:Halophilic microorganisms play important rules in salt field ecosystem and salt production. In this study, halophilic bacteria and haloarchaea from soils of Lianyungang Taibei and Yancheng Sanwei salt fields were analyzed. The halophilic bacterial and haloarchaeal types from both the soils were similar, but each soil had its distinctive species. A total of 17 halophilic bacteria were identified, among them, Halomonas was found from both the soils, while Pontibacillus and Halobacillus were isolated from Sanwei salt field only. Using uncultured 16S rRNA gene library technology, 13 haloarchaeal soil 16S rRNA genes were identified from both the saline soils. Halobacterium and Haloplanus were found from Taibei salt field, while Halobacterium, Natronobacterium, Halogeometricum and Haloarcula were identified from Sanwei salt field. Ten haloarchaeal 16S rRNA gene sequences showed 92%~97% identities with the GenBank sequences that appear to represent novel soil haloarchaeal species. This study provides important information that is useful for further investigation and application of halophiles of saline soil fields.

Abstract:Through the study of symbiosis of AMF (Arbuscular mycorrhizal fungi)-Amorpha fruticosa, the infection sequence, the infection rates and the chemotaxis between AMF and rhizobia had been determined. The diversity of infection between AMF and rhizobia in time-space under the inoculation conditions of mon-innoculation (AM+) and dipl-innoculation (AM++Rh+) was investigated and the relationship between AMF and rhizobia in the chemotaxis test was studied. The results suggested that there were some signals beween AMF and rhizobia and there exsited auxoaction in coordination during the formation of symbiosis. The chemotaxis between the root-exudates and rhizobia under the inoculation conditions of AM-+Rh-, AM+ and AM++Rh+ in 25℃, 28℃, 31℃ showed that the surrounding conditions (temperature) in rhizosphere have some effects on the regulation of incipient identification signals in the tri-symbiosis of AMF-host- rhizobia.

Abstract:Nutrient dynamics and bacterial diversity of traditional soypaste were analyzed and discussed with samples from Shandong province by nutrition and denaturing gel gradient electrophoresis (DGGE) analysis. The nutrition value was determined by following parameters: total acid, water-soluble carbohydrate (WSC), organic carbon (OC), crude protein (CP), amino-acid nitrogen and volatile products. Results showed that the total acid was increased at first, and decreased, and then increased again up to 6.26%. The contents of OC and WSC remained decline. As for CP, it was decreased after increased stable. The amino-acid nitrogen was kept increasing during the whole progress and its concentration was up to 101.2 g/kg in final soypaste. The concentration of lactic acid and glycerol were increased during the fermentation, and were up to 5.65 g/kg and 14.72 g/kg in final soypaste, respectively. DGGE analysis indicated that there were the most kinds of bacteria in 15d soypaste, and then some of bacteria were disappeared gradually. Uncultured bacterium, Lactococcus lactis and Bacillus licheniformis of final soypaste were predominant species in final soypaste.

Abstract:24 strains obtained from root nodules of Psoralea corylifolia, Pueraria lobata, and Campylotropis macrocarpa of Yunnan province were studied with numerical taxonomy and 16S rDNA PCR-RFLP. Results of numerical taxonomy indicated that all strains included 10 reference strains were divided into 3 groups at 84% similarity. Group III is an unknown group with no reference strains. Group I is slow-growing kind, and group II fast and middle-slow-grower. The dendrogram derived from 16S rDNA PCR-RFLP showed that all strains divided into five phylogenetic branches at the similarity of 70%. They are branches I and V with no reference strains, Agrobacterium-Sinorhizobium-Rhizobium, Mesorhizobium and Bradyrhizobium. Not all results of numerical taxonomy are accord with 16S rDNA PCR-RFLP, and 2 strains at the same group with A. tumefaciens IAM13129T.

Abstract:The process of U(VI) biosorption by freshwater algae Chlorella pyrenoidosa and its absorption mechanism, absorption thermodynamics and absorption kinetics were investigated in this paper. The effects of pH, contact time, initial U(VI) concentration and temperature on biosorption were studied respectively. Research result showed that the absorption effect of U(VI) by Chlorella pyrenoidosa was affected by pH value of solution to a great extent, the absorption reached its balance within 5 min with optimal pH value 6 and max absorption quantity 2.7 mg/g. On the other hand, the absorption quantity of U(VI) by Chlorella pyrenoidosa was positively correlated with the initial concentration of U(VI); and the absorption quantity did not fluctuate remarkably when temperature was varied at the range of 20℃ to 30℃. Research result also showed that the process of U(VI) absorption was congruent with the second order kinetic model, and the correlation coefficient was high reaching to 0.99. It was suggested that the U(VI) biosorption by Chlorella pyrenoidosa was a complicated process consisting of many simultaneous reactions and could be described by Languir model quite well.

Abstract:The experimental study of in-situ enhanced microbial ecological remediation for oil contaminated loess soil was carried out in oil production areas of North Shaanxi Province. In the experiments, the microbial ecological techniques of in-situ microbial communities combined with the physical and chemical methods as well as soil environment were used for the oil degradation and contaminated soil remediation. The results of the experiment showed that can degradation rate of oil can be up to 40.92% to 80.37% under oil average contents of 2754 mg/kg in the contaminated soil after the in-situ enhanced microbial ecological remediation for 11 to 32 days, which demonstrated the effectiveness of the in-situ microbial ecological remediation methods for oil contaminated soil in northwestern loess region. In addition, it was discussed for feasibility of extend application of the technique.

Abstract:Using the high efficient copper-adsorbing yeast strain Y17 as absorbing material, the major affect factors including pH, original concentration of Cu2+, cell biomass, adsorption time and temperature were examined, and then the absorbing sites of the Y17 was determined. The results showed that the solution pH was the most dominate factor which affected the biosorption of Cu2+, the other affecting factors were the initial concentration of Cu2+, the cell biomass added, and adsorption time, respectively; the temperature had little effect on the rate of biosorption. The orthogonal experiment showed that the optimal absorption condition was as follow: the solution pH was 5.0, the absorption time was 40 min, the cell biomass of Y17 added was 5.0 g/L, and the concentration of Cu2+ was 8 mmol/L; the highest adsorbing rate was up to 82.7% at this condition. Based on the results of different pretreatments and the desorption of Cu2+, the cell wall of Y17 was identified as the main place occurring boisorption process, and the -NH2 group, -COOH group on the surface of the yeast cells played an important role on the boisorption process.

Abstract:In order to determine the electrochemical activity of Shewanella decolorationis S12, anaerobic grown cells were scanned by the cyclic voltammograms (CV). The results of CV showed that strain S12 displayed certain electrochemical activities and could be used as a catalyzer working in microbial fuel cell (MFC) to produce electricity. The effects of different electron donor, such as lactate, formate and pyruvate with different concentration on the production of electricity were analyzed by using strain S12 in a single chamber MFC with a PEM/electrode assembly sandwiched type. The results showed that lactate was the optimal electron donor and the concentration of the electron donor determined the electricity generation capacity and potential development in the MFC. When 10 mmol/L and 20 mmol/L of lactate were used, the maximum power density of 21.93 mW/m2 and 55.72 mW/m2 were obtained, respectively.

Abstract:A strain which can synthesize medium-chain-length polyhydroxyalkanoate (PHAMCL) was isolated from soil. It was named as Pseudomonas mendocina NK-01 through classification and identification. The PHAMCL was synthesized by P. mendocina NK-01 from glucose in the condition of limited nitrogen source. The structure of it was characterized. In order to construct a recombined plasmid pBSphaC1, an expressing plasmid of E.coli, after phaC1 gene encoding PHA synthase was cloned from Pseudomonas mendocina NK-01 by PCR amplification, it was linked into pBluescript SK—. PhaC1 gene was expressed successfully in E.coli JM109. Fermentation synthesis was also investigated by recombined E.coli.

Abstract:Designed the degenerate primers of alcohol dehydeogenase and L-lactate dehydrogenase to augment Ethanoligenens harbinense B49 genomic DNA, and obtained about 780 bp and 610 bp PCR product respectively. Augmented flank sequences of the two PCR fragments with the Cassette PCR method. Similarity alignment showed that the products of the cloned DNA were very high similar to those of alcohol dehydrogenase genes and L-lactate dehydrogenase genes respectively. One of the two sequences was 1902 bp long, and the ORF of adh was 1101 bp long and encoded 366 amino acids. Its putative molecular weight was about 39.71 kD, its calculational isoionic point was pH 5.93. The maximal identity and positive was 51% and 73% with Clostridium thermocellum ATCC 27405 adh. The other one was 2490 bp long, and the ORF of adh was 951 bp long and encoded 316 amino acids. Its putative molecular weight was 34.23 kD, its calculational isoionic point was pH 6.09. The maximal identity and positive was 55% and 74% with Bacillus megaterium L-ldh. Successfully cloning these two genes would not only enrich the gene resources of L-lactate dehydrogenase and alcohol dehydrogenase genes, but also give the scientific warrant for the metabolic engineering research and the construction of the gene-engineering bacteria.

Abstract:我国是世界上环境污染最为严重的国家之一, 环境治理工作日趋重要。随着分子生物学技术的发展, 在环境微生物学领域的科研工作者的不懈努力下, 我国在环境微生物学方面取得了许多重要成果, 使微生物在环境保护中发挥着越来越重要的作用。为了展现国内环境微生物科研工作者取得的最新进展,《微生物学通报》针对“第十次全国环境微生物学术研讨会” 组织出版了这期“环境微生物专刊”, 期望该专刊的出版有助于我国环境微生物学相关领域的交流和发展。

Abstract:

Abstract:Viable but non-culturable state in bacterial cells as received uncultured microorganism has become the fundamental research issues in medical microbiology, epidemiology, general microbial ecology and sanitation quarantine since it was put forward in 1982. When in this state, bacterium are no longer able to grow and form colonies on conventional culture media, but maintain their patheogenicity, may become latent infection escaping detection to threaten enviroment and human security. With the development of modern molecular biology technique and metagenomics, it provide new research method and opportunity for uncultured microorganism in the environment. Recently, with the application of the metagenome technique, genetic fingerprinting technical etc, it becomes more and more popular. Simultaneously, along with this state become maturity in the laboratory. It provides a new research route for development and exploitation the uncultured microorganism.

Abstract:The microorganisms in the subterranean high-temperature petroleum reservoir is a kind of precious resource, which play an important role in matter circulation and energy flow in oil reservoir ecosystem. Traditionally, culturing techniques were used to analyze them, but it was hard to understand the microbial community diversity thoroughly. Molecular methods had overcome the pure culture bottleneck, which was very useful to analyze the environmental microbial community. In recent years, uncultured-based study of oil reservoir microbiology progressed rapidly, which produced important effect on the development of petroleum microbiology and ecology. In this paper, the current knowledge about molecular microbial ecology in petroleum reservoirs was reviewed and some suggestions towards further research were given.

Abstract:Every year, waters on earth receive large quantities of wastewater from industry, agriculture, fish and poultry raising, and municipal sewage treatment plants. Consequently, the aquatic environment on the earth is under a serious challenge from a very large quantity of pollutants such as antibiotics, insecticides, herbicides, hydrocarbons, etc., contained in the domestic wastewater, industrial and agricultural waste water and illegal effluents. In particular, with the development of intensive aquiculture and poultry, the effluent pollution has recently become more and more serious with more attentions. Furthermore more and more chemical pollutants discharged into aquatic environment have been detected with the advancement of analytical techniques. These chemicals can cause toxic effects on water habitats after discharged into aquatic environment. However, microorganisms have many key functions in pollution control. In this review, applications of microorganism in the degradation of chemicals in aquatic environments are reviewed. It was concluded that most applications of microorganisms degrading chemicals focused on aquaculture waters, whereas other aquatic systems (such as river, lake, sea, coastal waters) have been scarcely studied.

Abstract:The mass utilization of chemical fertilizer not only is a problem of environment, but also an energy issue. To inoculate beneficial microorganisms has been the topic of scientist to cope with it. The bacteria achieve the goal through the way of dissolving nutrients unavailable, restraining pathogeny, reducing deleterious compounds and so on. However, it should be colonized in soil first to realize its function. This paper summarized factors, both in biologic and abiological aspects that affected successful colonization and activity of bacterial inoculation. The impacts of inoculated bacteria on population structure of specific rhizobacterial communities and environment should also be paid an eye on.

Abstract:With the development of modern industry, the environment pollution caused by heavy metal such as lighly soluble Cr(VI) possesses the intense toxicity to human health. In the process of microbial metabolism, the Cr(VI)can be reducted to the Less soluble Cr(III) and the toxicity would be reduced effectively. There are several aspects summarized in the paper, such as microbial reduction Cr(VI)、the mechanism of microbial reduction Cr(VI)、problems in the reduction process and development direction.

Abstract:Synthetic pyrethroid insecticides have become one of the three major kinds of pesticide residues in the exported vegetabes and fruits in China nowadays. They also caused more and more acute or chronic poisoning affair and do great damage to human beings, aquatic biology and natural environment. As an efficient way to remove pesticides pollution, the biodegradation of pesticides has gradually become the hot issue in the field of environmental sciences. The study on the separation of degrading-bacteria and the extraction, purification, mechanism and immobilization of the degrading-enzyme of pyrethroids is reviewed in this paper. And the problems under resolved in the future work are also prospected.

Abstract:Purple bacteria are extensively used in bacterial photosynthesis research. This review describes the structure of light-harvesting I, light-harvesting II and reaction center of photosynthetic apparatus of purple bacteria and discusses the regulation mechanisms?of photosynthesis (PS) gene transcription, with an emphasis laid on the transcriptional regulation of PS gene by PpsR/AppA system.