The Research on Ten-Year Enrollment Data of Ethnic Pre-college in Guangxi——Study on the Reform for the Policy of Enrollment Ethnic Pre-college

对广西民族预科十年招生数据挖掘研究后认为:广西的民族预科招生政策既认真贯彻了国家层面预科教育发展的精神内核,又因地制宜地结合广西的实际,体现出民族预科招生政策鲜明的地方性,对其他民族地区的民族预科招生政策改革以及民族预科教育发展,都具有较强的政策效应。By probing into the ten- year enrollment data of ethnic pre- college in Guangxi, this paper gains that：the ethnic pre- college enrollment policy in Guangxi earnestly implements the spirit of national pre- col- lege education, and also refleers the locality of ethnic pre- college enrollment policy , so it have great policy ef-fects on the ethnic pre - college enrollment policy in other minority areas and the development of ethnic pre - col- lege education.中央民族大学“民族教育应用研究奖学金”;广西教育科学“十二五”规划课题之“广西民族预科教育招生政策的研究”(2012ZKS003)的阶段性成

Method for improving hydrogen yield of hydrogen production bacteria

本发明属于微生物技术应用领域，具体的说是一种提高产氢菌氢产量的方法。将产氢菌株接种至含2.5‑20mmol/L的铁氧化物的培养基中，通过暗发酵培养，即可实现产氢菌株的大量产氢。本发明水铁矿和磁铁矿的添加促进了产氢梭菌C.pasteurianum的生长，进而加速了该菌底物转化效率，并提高了代谢产物氢气、乙酸和丁酸的产量。该发明方法，极大提高了产氢梭菌氢产量，为实现微生物暗发酵产氢大规模生产提供了理论支持

Mechanisms of extracellular electron transfer in the biogeochemical manganese cycle

Microorganisms are important driver for the circulation of biogeochemical elements and play a vital role in the redox of metal elements possessing variable valence such as manganese.In recent years,the discovery and wide distribution of Mn(Ⅲ) in certain environment enrich our knowledge of natural manganese cycle.Some reports showed that geochemical cycling of manganese,especially dissimilatory manganese reduction,was closely related to microbial extracellular electron transfer,and dissimilatory manganese reduction involves five mechanisms of extracellular electron transfer.In this review,we discuss geochemical cycling and significance of manganese;microbial diversity of manganese cycle involving three aspects:mechanisms of microbial extracellular electron transfer,manganese oxidation mediated by microorganisms and manganese reduction mediated by microorganisms;The environmental significance of microbial geochemical manganese cycle.The research on the process of manganese cycle not only enriches related theories,but also stimulates the development of application including biological manganese removal,in-situ remediation of contaminants and bioleaching

Hydrogen-producing and electrochemical properties of a dissimilatory Fe(III) reducer Clostridium bifermentans EZ-1

[Objective] To obtain and characterize a versatile strain isolated from the soil of Yellow River Delta.[Methods] The strain was isolated by anaerobic technologies and identified by sequencing the 16S rRNA gene.The morphology was depicted with Gram staining and scanning electron microscope.High performance liquid chromatography and gas chromatography were used to analyze the metabolic substrates and productions.Ferric citrate (FeC6H5O7),ferrihydrite (FeOOH) and magnetite (Fe_3O_4) were supplied to detect the capability of Fe(Ⅲ) reduction of this strain.Microbial fuel cells were constructed with graphite as electrodes to test the electrochemical activity of this strain.[Results] Compared to Clostridium bifermentans,the similarity of 16S rRNA gene is 97.99%.It is a rod,Gram-positive bacterium,which can use glucose to produce hydrogen,carbon dioxide,acetate and butyrate.The Fe(Ⅲ) reduction results showed that it could reduce soluble ferric citrate,amorphous ferrihydrite and crystal magnetite.Furthermore,the electrochemical activity was detected and the maximum current density peaked at 6.5 mA/m~2.[Conclusion] In this work,a versatile strain which is capable of producing hydrogen,electricity and reducing iron oxide,was successfully isolated from the soil of Yellow River Delta named as Clostridium bifermentans EZ-1

Diversity of archaea in the sediments from different areas of the Bohai Sea

Methanogens play an important role in the carbon cycle of coastal sediments. In this study, sea water enrichment cultures with acetate as the substrate were employed to enrich methanogens using sediments of the Bohai Sea. The methane production was used to estimate potential methane productivity and terminal restriction fragment length polymorphism analysis was used to analyze the diversity of microbial communities simultaneously. Our results revealed that changes in the bacterial and the methanogens community structures in sediments from different areas of the Bohai Sea were found. The dominant methanogens were Methanobacterium and Methanolobus in sediments of the Bohai Sea, and Desulfovibrio and Thiobacillus were the dominant bacteria. Different areas of the Bohai Sea obviously varied on methane production, which shows that the methane emission is higher in the coastal area. Bohai Sea has great potential for methane productivity and acetic acid conversion rate(46.46%), and the estimation of potential methane production is 1.74 Gt per year

Effects of water conditions on the diversity of soil microbial communities in the coastal reed wetlands

River-sea water interactions in coastal wetlands dramatically affect soil redox potential and cause variations in nutrient elements. In this study, we analyzed the changes in physicochemical properties of soil, diversity in the microbial community, and the Fe(III) reduction activity of microorganisms in reed wetlands of the Yellow River Delta under different water conditions. The results showed that the salinity, pH value, and concentrations of organic carbon, total nitrogen, and Fe(II) in the soil were higher in the flooded reed wetlands as compared with the ammonium concentration. The genera Alishewanella, Cellulomonas, Sphingomonas and Pseudomonas were the dominated bacteria in flooded reed wetlands, whereas Methanosarcina and Methanobacterium were the dominant archaea. Further, the dominated bacteria and archaea in the non-flooded reed wetlands were Cellulomonas, Acidovorax, Geobacter, Thiobacillus, and Methanosarcina, respectively. A shift in the iron-reducing bacterial community structure was also observed in the enrichment samples from flooded and non-flooded reed wetlands. Paracoccus, Geobacter, Alishewanella, and Thiomonas were the dominant iron-reducing bacteria in the flooded reed wetlands, and the dominant genera of iron-reducing bacteria in the non-flooded reed wetlands were Geobacter and Azospira. The diversity of soil bacteria, archaea, and iron-reducing bacteria was higher in the flooded reed wetlands. The Fe(III) reduction activity of iron-reducing bacteria in the reed wetlands was lessened to a certain extent by perennial flooded conditions

Potential direct interspecies electron transfer (DIET) from Clostridium spp. to Methanosarcina barkeri in amethanogenic isolation

【目的】革兰氏阴性菌Geobacter metallireducens可以与乙酸型产甲烷菌Methanosaeta harundinacea或Methanosarcina barkeri通过种间直接电子传递(DIET)还原CO2产甲烷。本实验室前期的研究发现Methanosarcina mazei和Geobacteraceae在铁还原富集培养中形成团聚体,可能存在直接电子传递。然而,革兰氏阳性菌(如Clostridium spp.)与产甲烷菌是否存在种间直接电子传递尚不明确。【方法】采用Hungate厌氧滚管法,以乙醇为唯一电子供体从铁还原富集培养体系中获得产甲烷分离物(S6)。通过T-RFL..

Potential direct interspecies electron transfer (DIET) from Clostridium spp. to Methanosarcina barkeri in methanogenic isolates

[Objective] Geobacter metallireducens, a Gram-negative bacterium, can directly transfer electron to acetoclastic methanogens such as Methanosaeta harundinacea and Methanosarcina barkeri for reducing carbon dioxide to methane. Our previous results showed that Methanosarcina mazei and Geobacteraceae formed aggregates in an iron(III)-reducing enrichment culture indicating direct interspecies electron transfer. However, the capability of direct electron transfer with methanogens for Gram-positive iron(III)-reducing bacteria such as Clostridium spp. is still unknown. [Methods] In this further study, methanogenic isolates(S6)were achieved from the iron(III)-reducing enrichment by roll-tube(Hungate)method with ethanol as the sole electron donor. We used terminal restriction fragment length polymorphism(T-RFLP)and clone library analysis to investigate the community of S6 and used electrochemical method such as cyclic voltammetry(CV)to confirm the electroactivity of isolates. [Results] Clone library analysis of 16S rRNA gene showed that Clostridium spp.(close to C. tunisiense)and Methanosarcina barkeri were predominant in the bacterial and archaeal community, respectively. Interestingly, addition of G. metallireducens into S6 did not increase the ability of both iron(III)reduction and methanogenesis, indicating that Clostridium spp. may play a similar role in direct interspecies electron transfer from G. metallireducens to M. barkeri. Furthermore, current generation of the S6 suspension dramatically decreased when contact between the organisms and the electrodes was prevented by dialysis bag, and CV showed no obvious redox peaks. [Conclusion] These results suggested that there was direct electron transfer in the methanogenic isolates. This work demonstrated that the dominant Gram-positive Clostridium spp. can potentially directly transfer electron to M. barkeri in methanogenic isolates

Multifunctional double-enzyme clostridium and application thereof

本发明属于微生物技术领域，具体涉及一种多功能新型双酶梭菌及其在发酵产氢、提高乙酸产量中的应用。菌株为双酶梭菌Clostridium bifermentans EZ‑1，保藏号为CGMCC NO.13913。本发明所得菌能利用葡萄糖产生清洁燃料氢气以及乙酸和丁酸等代谢产物。适当浓度纳米磁铁矿和水铁矿的添加可以调节该菌代谢途径从而增加乙酸产量。通过微生物燃料电池检测发现，该菌株具有产电能力，最大电流输出密度可达6.3mA/m2。该菌株是目前报道的首例多功能新型双酶梭菌，可应用于生物质发酵产氢、乙酸和丁酸等生物制品且具有产电潜力，具有广阔的应用前景