Abstract:“第十四次全国环境微生物学术研讨会暨简浩然先生诞辰100周年纪念”于2011年11月25?28日在福建厦门隆重召开, 本次会议围绕“环境微生物与生态保护”的主题, 在环境微生物学研究前沿、微生物资源发掘与应用、节能减排、循环经济、污染环境生物修复与环境保护工程等诸多领域阐述了最新研究进展并展开了深入的研讨。为了展现国内环境微生物及相关交叉领域科研工作者取得的最新进展, 《微生物学通报》针对“第十四次全国环境微生物学学术研讨会”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促进我国环境微生物学相关领域的交流与发展。

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Abstract:[Objective] To identify the black yeast-like fungus isolated from the radiation-polluted soil and investigate the resistance. [Methods] the colony morphology and mycelium of isolates was observed, and phylogenetic tree was constructed based on LSU rDNA D1/D2 domain sequences. And then, the isolates resistance to 60Co gamma rays and ultraviolet rays and stress resistance to heavy metals and salt were analyzed. [Results] The results showed that isolates were varieties of Aureobasidium pullulans. The isolates F99 and F134 had a high similarity (100%) with A. pullulans var. subglaciale CBS 123388T as the closest relative, and the isolate F19 had a high similarity (100%) with A. pullulans var. melaogenum CBS 105.22T as the closest relative. Furthermore, isolates had higher radiation resistance and stress resistance. [Conclusion] This paper provides important materials to investigate the mechanism of radiation-resistant fungus.

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Abstract:[Objective] Partial nitrification-anammox is considered as the shortest?process for biological nitrogen removal and partial nitrification is the important part of this process. [Methods] The variation of functional bacteria during start-up and stable operation of partial nitrification process was investigated in a SBR bioreactor in this study. [Results] The results indicated that ammonia-oxidizing bacteria (AOB) population was expanded significantly and nitrite-oxidizing bacteria (NOB) population was inhibited when DO concentration was controlled lower than 1 mg/L and ammonia loading of the influent increased gradually. As a result, start-up and stable operation of partial nitrification process was realized. When ammonia volumetric loading of the influent was 0.055 kg/(m3·d), the average ammonia removal volumetric loading and sludge loading were 0.043 kg/(m3·d) and 0.16?kg/(kg·d), respectively. In addition, the average nitrite accumulation rate was 83.4% at this time. AOB population density and relative abundance increased from 4.5×104 CFU/mL to 1.5×107CFU/mL and from 0.18% to 7.25%, respectively, during start-up and stable operation of partial nitrification process. At the same time, NOB population density and relative abundance decreased from 2.0×105 CFU/mL to 1.5×104 CFU/mL?and from 5.51% to 2.14%, respectively. [Conclusion] The expansion of AOB population was responsible for realization of partial nitrification and ammonia removal. High ammonia concentration and loading?also caused the activity inhibition of partial nitrification.

Abstract:[Objective] The aim of this study was to investigate the actinobacteria diversity of the saline-alkali soil from Hongjingzi located in XinJiang Province. [Methods] The diversity of actinobacteria in this soil was investigated by using culture-independent method based on phylogenetic analysis of 16S rRNA gene sequences. The specific primers for the class Actinobacteria were used to amplify the partial 16S rRNA gene, and then clone library for the soil sample was constructed. A total of 246 positive clones chosen randomly from the clone library were digested with Hae III for RFLP analysis. [Results] Among of them, 61 different clones selected were sequenced. The analysis of 16S rRNA gene sequences showed that the clone sequences went back to 42 OTUs and belonged to subclasses Actinobacteridae, Acidimicrobidae and Rubrobacteridae respectively. The 71.4% of the detected sequences from this soil was less than 97% similarity to the published sequences, which might represent new taxa. Some sequences, which formed several distinct clades in phylogenetic tree may represent new taxonomical groups of actinobacteria. [Conclusion] These results indicate that the soil from Hongjingzi region be abundant actinobacteria, including large number of unknown actinobacterial taxa, which would be further explored.

Abstract:[Objective] Analyzing the bacterial diversity, physiological and biochemical characteristics in the mogao grottoes can provide an experimental basis for microbial disease prevention and treatment of Mogao murals. [Methods] Both the air and mural samples collected from Mogao Grottoes 245# are analyzed by means of pure culture techniques, and testing effect of mural paint on bacterial growth. [Results] 76 bacteria belonging to eight different genera are identified and characterized. Six genera are revived form the air, they are Bacillus, Arthrobacter, Pseudomonas, Acinetobacter, Enterobacter, Kocuria, Among them, Bacillus and Arthrobacter are dominant. Four genera are revived from the mural, they are Bacillus, Arthrobacter, Paenibacillus, Erythrobacter, among them, Bacillus and Arthrobacter are dominant; and it is found that some bacteria, such as DHXJ05 (Enterobacteriaceae), DHXJ08 (Bacillaceae), DHXJ15 (Erythrobacteraceae), DHXJ16 (Bacillaceae) and DHXJ17 (Bacillaceae) can grow well in environment containing red ferric oxide, red lead, and cinnabar. [Conclusion] This experiment provide the conditions for discolorment mechanism and choosing corresponding bacterial preparation.

Abstract:[Objective] In order to understand the interaction between heavy metal contamination and microbial diversity better, 16 wild field samples including tailing samples, near grain and vegetable soil samples were obtained from the 4 # tailing site of Dexing copper mine, Jiangxi province, China. On the one hand, number of culturable heterotrophic bacteria in samples was counted by plate method. [Methods] On the other hand, the diversity of culturable and unculturable microbial communities was further investigated by denaturing gradient gel electrophoresis (DGGE). Principle component analysis (PCA) was used to reveal the influences of physico-chemical characteristics, contents of chemical/heavy metal elements on the diversity of culturable heterotrophic bacteria and microbial community. [Results] Results of elemental analysis revealed that these samples subjected to different levels of contamination by heavy metals Cu, Cd, Zn, Ni, Pb and Cr. Number of culturable heterotrophic bacteria was the least in tailing samples, and increased significantly in vegetable and grain soil samples. The diversity index of the samples (Shannon-Weaver index H) was calculated, and it found the greatest diversity of microbial community present in samples, which were at middle distance away from the mine tailing site and had middle level of heavy metal concentrations. PCA analysis showed that the number of culturable heterotrophic bacteria had significant relativity to the physic-chemical properties such as organic carbon, organic matter, moisture content and so on, except for heavy metals. For diversity index H, except above physico-chemical properties, some heavy metals such as Ag, Zn, As, Pb, Ni and Cr had significant influences on it. While heavy metals such as Cu and Cd, which were present in the samples with relatively high concentrations, did not become major factors affecting microbial diversity. [Conclusion] The results from these long-term heavy metals contaminated wild field samples, may indicate that the influence of different heavy metals on microbial diversity is not laboratory studied simple linear relationship with their concentrations.

Abstract:[Objective] The study aims to determine whether the termite-inhabiting soil harbors cellulose-degradation bacteria. [Methods] Using a selective medium supplemented with sodium carboxymethyl cellulose (CMC-Na) as the sole carbon source and the Congo red activity staining method, we have isolated a cellulose-degradation strain. Microscope morphology, Gram-staining, and 16S rRNA gene sequencing analyses were utilized to characterize the isolated strain. Enzyme activity and properties were assayed by the DNS method. [Results] A Gram-positive strain (named as TT15) with high cellulase activity was obtained from a Coptotermes formosanus-inhabiting soil. Based on the 16S rDNA analysis, TT15 was identified to be a strain of Bacillus cereus Gd2T. The cellulase activity was not detected in the first 12 h of continuous culture, but afterwards, the enzyme activity was detected and increased with culture time. The activity reached the maximum level at the early stationary phase of growth (48 h) and remained stable later on. The optimum pH and temperature were 5.0 and 50 °C, respectively. [Conclusion] We have isolated a B. cereus Gd2T strain TT15 with high cellulase activity from a C. formosanus-inhabiting soil. The strain might be used for biomass conversion biotechnology.

Abstract:[Objective] In order to improve arachidonia acid (ARA) production, and prevent the degeneration of ARA-producing strain Mortierella alpina in long-term culture preservation and cultivation, which could lead to low consumption rate of substrates like carbon source. [Methods] Mortierella alpina strain was first domesticated in high-sugar PDA plate with gradient sugar content (2%、5%、7%、10% and 15%). The strain which grew better in the solid medium containing 10% sugar was then selected and transferred to two liquid high-sugar media with different nitrogen sources to domesticate. The gradient sugar contents were 3%、4%、5% and 6%, respectivlely. Finally, the domesticated strain was used to produce ARA in a 2 L bioreactor. [Results] The experimental results show that the consumption of sugar increased from 3 g/(L·d) up to 12 g/(L·d) in the medium with yeast extract, and from 7 g/(L·d) up to 12 g/(L·d) in the medium with corn steep liquor. After cultivation for 144 h in a 2 L bioreactor, the yield of ARA reached 8 g/L, which was 4 times higher than that obtained with the original strain. [Conclusion] The domestication of the high-sugar-tolerant Mortierella alpina increased the consumption of sugar, biomass, total fatty acid and ARA production. The domesticated strain could maintain the high sugar resistance in the preserving process and turn to be more stable.

Abstract:[Objective] Contamination of micro-organisms attached on surface materials is one of the greatest threats for public health. Using copper alloys to replace stainless steel can reduce the use of disinfectants and the spread of bacteria. [Methods] In this study, the bactericidal abilities of different copper alloys through the survival of 3 Staphylococcus aureus and two Escherichia coli strains five different bacterial strains were investigated. [Results] The results revealed that the bactericidal abilities of the copper alloys are positively related to the copper content; the survival of the bacteria belonging to the same genus are similar; there was not direct relation between the bactericidal efficiency of the copper alloys and copper-resistances; the bactericidal efficiency of the copper alloys appeared to correlate with the bacterial cell wall structures. [Conclusion] The copper alloys are good materials with bactericidal abilities.

Abstract:[Objective] We aim to find the new genes with biocatalytic potential from the plant microbiota metagenomic library by the means of high-throughput screening combined with multiple hybridizations based on probe stripping. [Methods] First, the phage particles were used to infect EPI300?-T1R E. coli cells according to the titer of the phage particles as a primary library. After incubation the mixture was then divided into aliquots of 96 and cultured in the medium overnight, followed by storage in 2-mL 96-well plates. The resulting fosmids were hybridized to screen the library for the new enzyme genes. [Results] We found a thoroughly removal of the probe by striping the nylon membrane as described here, and the target DNA on the nylon membrane can be used repeatedly for at least 7 times. All these resulted in a highly efficient means for storage and screening of the metagenomic library. [Conclusion] By using the enoate reductase and short-chain dehydrogenase (SDR) as probes, candidate fosmid clones were obtained after two cycles of screening. Based on fosmid sequence analyses, new homologues of enoate reductase and SDR were found and cloned for subsequent heterologous expression and enzymology.

Abstract:[Objective] The objective of this study was to examine the production of siderophore, taxonomic position and antifungal activity of high yield siderophore-producing bacteria isolated from Xinjiang cotton field soil. [Methods] high yield siderophore-producing bacteria were isolated by modified sugar-aspartic acid (MSA) medium and siderophore activity was measured by spectrophotometer method. The inhibitory effect against fusarium wilt pathogens (Fusarium oxysporum) was measured by mixed culture method. The strain SS05 was identified according to morphological features, physiological and biochemical characteristics and 16S rDNA sequences of the strain. [Results] There were 163 siderophore-producing bacteria strains isolated from cotton soil and 21 of 30 tested strains has high siderophore-producting capacity. The total siderophore relative content of strain SS05 was 98.3%. The supernatant of SS05 cultured with low concentrations of Fe3+ has significant inhibitory effect against F. oxysporum. Strain SS05 was identified as Bacillus sp. and has the closest genetic relationship with Bacillus mojavensis. [Conclusion] Strain SS05 was a high yield siderophore-producing bacterium, had the closest genetic relationship with Bacillus mojavensis. The supernatant of SS05 cultured with low concentrations of Fe3+ has significant inhibitory effect against F. oxysporum.

Abstract:[Objective] In order to study control strategy of the Microcystis aeruginosa by native microorganism from Qingcaosha Reservoir water, the anti-Microcystis aeruginosa bacterium was isolated from Qingcaosha Reservoir water and its inhibitory effect on Microcystis aeruginosa was investigated. [Methods] Based on isolating and screening the bacteria cultured from the reservoir water, a strain CL capable of inhibiting Microcystis aerginosa was obtained. The inhibiting performance and influences parameters, such as culture time and concentration of bacterium on inhibitory effect were studied and 16S rDNA sequence analysis was done. [Results] Results showed that the inhibitory ratio would reach 45.4% when bacterium concentration ranged from 4.5×108 CFU/mL to 8.4×108 CFU/mL. Inhibitive effect first increased and then dropped with the culture time, the maximum inhibitory ratio appeared in the sixth day. 16S rDNA sequence analysis revealed that the strain CL belongs to stentrophomonas genus of xanthomonas family. [Conclusion] A native bacteria named stentrophomonas capable of inhibiting Microcystis aeruginosa was isolated from Qingcaosha Reservoir water, which has a certain potential use in controlling Microcystis aeruginosa of Qingcaosha Reservoir.

Abstract:[Objective] Recently, as the prevalence of multiple antibiotic resistant bacteria in environments are induced by the extensive use of antibiotics by human, a better understanding of the distribution, transport and dissemination of antibiotic resistance genes (ARGs) in environments is warranted. The objective of this study was to determine the pollution levels of antibiotic resistance genes in Jiulong River estuary and wastewater treatment plants (WWTPs) in Xiamen. [Methods] Polymerase chain reaction (PCR) assays were employed to identify the distribution patterns of four sulfonamide, thirteen tetracycline ARGs and two integron genes in water, sediments of Jiulong River estuary and five activated sludges in WWTPs of Xiamen. Clone libraries of the tet(W) gene were also generated from three sediments of Jiulong River estuary and five WWTPs in Xiamen. [Results] The all ARGs has been dectected except tet(O) and tet(S). The results demonstrated that the frequency of detection (FOD) of ARGs and integron genes in environmental samples with the highest FOD in activated sludges (0.86), moderate FOD in sediments (0.57) and the lowest FOD in water (0.24). Furthermore, the FODs of sul(l), int(1), tet(A), tet(C), tet(E), tet(M) and tet(W) were higher in freshwater and brackish water than those in seawater, suggesting that ARGs may be transported from the upstream of Jiulong River. [Conclusion] Principle component analysis also supported the suggestions that WWTPs contained the highest ARGs, and ARGs are enriched in sediments but unstable in water. In addition, the results of tet(W) libraries indicated that WWTPs may be a point source of ARGs into Jiulong River estuary and Xiamen sea.

Abstract:[Objective] The research focus on cloning endoglucanase I (egI) gene from Penicillium decumbens L-06 and expressing in Escherichia coli with high efficiency. [Methods] egI gene was cloned from Penicillium decumbens L-06 by RT-PCR method. Recombinant plasmid pET32a-egI was constructed and was transformed into Escherichia coli rosetta(DE3). Recombinant protein with His-tag was expressed in E. coli rosetta(DE3) after induction with IPTG and then was purified with the Ni-NTA affinity chromatography. [Results] As expected, the relative molecular mass was approximately 80kD after analyzed by SDS-PAGE and Western blotting. Hydrolysis activity of recombinant protein was assayed by cellulase activity staining and DNS method (2.56 IU/mL). [Conclusion] The results achieve the purpose as constructing prokaryotic expression system and expressing egI gene.

Abstract:Methane, an even more serious greenhouse gas than carbon dioxide, could be reduced effectively via anaerobic oxidation. According to standard Gibbs energies, it can be oxidized into carbon dioxide under anaerobic condition, when oxides e.g. SO42?、Mn4+、Fe3+、NO3? act as the electron acceptors. This paper focus on the mechanism, characteristics of methanotrophic bacteria and reaction condition of anaerobic oxidation driven by sulfate or nitrate. The problems and prospect of the research are also indicated. Reverse methanogenesis, acetogenesis and methylogenesis are three possible pathways in anaerobic oxidation driven by sulfate, whereas aerobic or anaerobic methane oxidation coupled to denitrification are probably the pathways when NO3? serves as the electron acceptor. The concentrations of methane, SO42? or NO3? and organic content, as well as environmental conditions will dramatically affect anaerobic methane oxidation.

Abstract:Estrogens in the environment are important environmental endocrine disrupting chemicals, and the major way to remove them is through microbial degradation. This paper reviews four aspects of the microbial degradation of estrogens, including the reported estrogen-degrading bacteria, degradation mechanisms, the estrogen degradation pathway and estrogen degradation by eukaryotic microorganisms. In the end, future research directions of microbial degradation of estrogens are suggested.