4种理化因子对菌株XH1硝化效果的影响

【背景】基于硝化菌群的富集培养技术可高效稳定地去除养殖水体中的有害氮素,而当前在水产养殖领域有关硝化菌群定向培育及硝化功能菌株的研究较少。【目的】研究不同盐度、pH、温度、通气量条件下硝化菌群分离菌株XH1的生长及其对氨氮和亚硝氮的去除效果。【方法】设置不同梯度的盐度、pH、温度、通气量条件,通过计数菌量、测定氨氮及亚硝氮的浓度变化,比较不同条件下菌株XH1的生长及其对氨氮和亚硝氮的影响。【结果】菌株XH1可在盐度5‰-35‰、pH 6.0-9.0、温度15-45°C和通气量0.5-1 V/(V·min)的条件下生长良好,菌量最高可达2.34×109cells/mL;在盐度5‰-35‰、pH 6.0-9.0、温度15-30°C、通气量0.5 V/(V·min)的条件下,对氨氮的去除效果显著(P0.05),在第1-3天对培养液中氨氮的最高去除率可达86%-97%,但培养液中的氨氮浓度先降后升;对亚硝氮的最高去除率达68%。【结论】菌株XH1对盐度、pH、温度等主要环境因子具有良好的适应性,其对水体氨氮的去除效果良好,可作为中低盐度养殖池塘水体氨氮防控菌剂产品研发的备选菌株。     

一株人参内生1-氨基环丙烷-1-1羧酸(ACC)脱氨酶活性细菌的筛选、鉴定及其对宿主生长的影响

【目的】从人参内生细菌中获得具有1-氨基环丙烷1-羧酸(ACC)脱氨酶活性的菌株,并进行促生效果的验证。【方法】结合初筛和复筛的方法筛选具有ACC脱氨酶活性的人参内生菌株;采用Ashby培养基和固氮酶基因验证其固氮潜能;菌碟法及钼锑抗比色法测定其解磷能力;CAS方法检测产生铁载体能力;通过室内及田间试验测定菌株对人参生长的促进作用。通过形态学、生理生化测定及16S rRNA序列分析明确菌株的分类地位。【结果】从120株人参内生菌中获得了一株具有较高ACC脱氨酶活性的菌株JJ8-3,其酶活性为α-酮丁酸6.7μmol/(mg·h);且具有解磷特性、固氮潜能和产生铁载体能力;能明显促进人参种子及根部的生长;经鉴定菌株JJ8-3为荧光假单胞菌(Pseudomonas fluorescens)。【结论】获得了一株具有ACC脱氨酶活性的人参内生细菌,将为其在促进植物生长中的应用和研究奠定基础。     

基于环境微生物资源库快速构建易腐垃圾高效堆肥复合菌剂

【目的】针对易腐垃圾成分快速构建一种高效堆肥复合菌剂。【方法】研究以"中国科学院战略生物资源服务网络计划"支持建设的微生物资源库为基础,根据菌株产酶活功能信息,针对易腐垃圾有机成分定向挑选出高产酶(蛋白酶、淀粉酶、纤维素酶、木质素酶、脂肪酶)菌株,通过测定菌株间拮抗作用,构建了一种高效堆肥复合菌剂CM菌剂。进行了菌剂发酵条件优化和易腐垃圾堆肥应用研究。【结果】CM菌剂最适发酵条件为接种7%的种子液于红糖培养基中,30°C下培养48h,此时菌剂产生蛋白酶、淀粉酶、纤维素酶、木质素酶、脂肪酶酶活分别为181.76、52.92、1.57、12.81、9.94 U/mL。堆肥结果表明CM菌剂堆肥产品pH、含水率、有机质含量均满足生物有机肥标准(NY884-2012)。CM菌剂堆肥过程中最高温度为63.5°C,高温期9–12 d,30 d后含水率为28.7%,有机质降解率为30.4%,C/N为8.93,与商品菌剂BM相比堆肥效果更好,可使堆体高温期延长4–7d、含水率降低3.8%,可加快易腐垃圾中有机质降解,降解率提升6.2%,并具有更强的固氮能力,缩短腐熟时间,提升堆肥产品品质。【结论】基于环境微生物资源库功能信息构建堆肥复合菌剂是一种快速有效的菌剂构建方法。     

耐盐硫氧化菌的筛选、鉴定及脱硫性能研究

【目的】从典型自然环境中筛选耐盐高效硫氧化菌,研究其生长特性,并进行初步脱硫实验。【方法】以硫代硫酸钠为唯一能源底物的培养基富集脱硫菌,经过3次平板划线培养、纯种分离后得到纯种培养。经过革兰氏染色、平板菌落形态观察及形态学特征研究,并结合16S rRNA基因序列分析及分子系统发育树的构建结果,确定菌株的种类。【结果】从上海外高桥某发电厂冷却水池中筛选分离出一株硫代硫酸盐去除率高、耐盐性较强的细菌,命名为CYJN-1。该菌为革兰氏阴性菌,短杆状,鉴定为那不勒斯菌(Halothiobacillus neapolitanus)。H. neapolitanus CYJN-1具有较强适应盐度变化的能力,菌株生长的盐度范围为0?5% (NaCI,质量体积比)。菌株最适生长条件为：温度30 °C、pH 7.0、底物浓度为20 g/L。在此条件下,该菌对硫代硫酸钠的去除率可达98%。【结论】H. neapolitanus CYJN-1耐盐性较强,硫代硫酸盐去除率高,在生物脱硫、生物冶金等领域都具有潜在的应用前景。     

联合固氮菌叶面接种剂的优化及其在玉米叶际的定殖

【背景】联合固氮菌由于不具有宿主专一性,在土壤、叶际中广泛存在,对生态系统氮素供应有着重要贡献,它还可以通过分泌生长激素等间接作用促进植物生长,可作为重要的农业生产菌剂。土壤接种剂由于受土著微生物的竞争和土壤抑菌物质等的影响,接种效果不稳定,难以推广使用。相比于土壤环境,叶际生境相对简单且表面积巨大,进行叶际接种是固氮菌剂推广应用的一个新思路。【目的】优化联合固氮菌菌株W12接种添加剂,制备液体接种剂并研究其在玉米叶际的定殖效果。【方法】对菌株W12进行菌落PCR测序,构建系统发育树并确定分类地位。分别在培养液中添加不同浓度梯度的羧甲基纤维素(Carboxymethyl cellulose,CMC)和甘油(Glycerol,Gly),测量菌株W12生长曲线和固氮酶活性,优化添加剂浓度并制备液体接种剂,对接种剂的有效保存时间进行检测。将接种剂喷洒到玉米叶际,测量其对玉米产量和植株含氮量的影响,并通过低氮培养基进行回收计数。【结果】固氮菌菌株W12的16S r RNA基因序列与变栖克雷伯氏菌(Klebsiella variicola)的相似性高达99%,在培养液中添加CMC和甘油对菌株W12的生长无明显促进和抑制效果,但均提高了固氮酶活性。添加甘油制备的接种剂在盆栽和大田玉米叶面喷施后,在玉米生长末期叶际回收到的W12类似菌分别为4.3×105 CFU/g叶片和1.7×105 CFU/g叶片,显著高于未接种的处理;而且大田玉米籽粒、茎部和叶片的含氮量高于不接种的对照处理。经过90 d贮藏后,4°C保存的接种剂剩余活菌数均高于1.0×108 CFU/m L。【结论】羧甲基纤维素和甘油的添加不仅有利于固氮菌液体接种剂在叶片的附着,并能显著提高联合固氮菌菌株W12的固氮酶活性,低温冷藏可保证液体接种剂的有效活菌数;液体接种剂在玉米叶际喷施后,菌株W12能够成功定殖,并显著提高玉米植株和籽粒含氮量。研究结果为固氮菌叶面接种剂的制备和应用,以及实现农业氮肥减施保产的目标提供了借鉴意义。     

一株高效解磷肠膜明串珠菌的分离鉴定及解磷能力研究

【背景】植物根际土壤含有多种溶磷微生物,但是具有溶磷能力的肠膜明串珠菌未见报道。【目的】从脐橙根际土壤分离高效解磷菌,研究其解磷应用。【方法】通过初筛和复筛从23株菌中筛选解磷能力较强的菌株,同时采用钼蓝比色法测定磷含量。通过测定发酵液中小分子有机酸含量、磷酸酯酶酶活及pH值的变化,探究菌株的解磷机理。【结果】经过筛选得到9株具有一定解磷能力的菌株。通过菌种16S rRNA基因序列分析和生理生化实验确定其中一株菌为肠膜明串珠菌,命名为肠膜明串珠菌G7。培养基初始pH6.0、碳源为葡萄糖、氮源为硫酸铵时G7的解磷能力较佳。G7发酵过程中产生大量有机酸,而其酸性磷酸酯酶活性高于碱性磷酸酯酶。【结论】碳源、氮源以及初始pH值都能影响G7的解磷能力,其解磷能力主要缘于在发酵过程中产生了大量小分子有机酸,关于G7的解磷机理还需要更深入的研究。     

一株高效解无机磷细菌BS06的鉴定及其解磷能力分析

【目的】对一株来源于广西甘蔗根际土壤的高效解无机磷细菌BS06的分类和解磷能力进行探讨,以期为解磷微生物在广西甘蔗生产上的开发和应用提供理论依据。【方法】通过形态观察、生理生化测定及16S rRNA基因序列同源性分析,进一步结合种特异的recA基因序列分析对解磷菌BS06进行分类鉴定;通过改变无机磷培养基中的碳源、氮源对菌株解磷能力的影响,分析菌株的解磷特性;通过盆栽试验了解菌株对甘蔗品种粤糖00236、桂糖28磷素吸收的影响。【结果】分类鉴定结果表明菌株BS06属于洋葱伯克霍尔德菌(Burkholderia cepacia);菌株在以乳糖为碳源条件下具有较强的解磷能力,其发酵液中水溶性磷含量为262.71 mg/L;在以硝酸钠为氮源条件下有较强解磷能力,其发酵液中水溶性磷含量达到305.85 mg/L;接种BS06菌株显著促进甘蔗组培苗的生长并提高甘蔗植株的含磷量。【结论】解磷细菌BS06具有较大的开发利用潜力。     

3种水稻土中7株固氮蓝细菌的分离与特征

【背景】蓝细菌是水生和陆地生态系统中生物固氮的主要贡献者。【目的】增加对稻田土壤固氮蓝细菌的了解,获得用于进一步研究的可培养固氮蓝细菌菌株。【方法】选择3种具有不同固氮能力的水稻土,采用BG11-N培养基分离培养固氮蓝细菌菌株,对新分离菌株进行形态特征观察,通过基因组DNA的nifH基因扩增明确其固氮潜力,进一步采用乙炔还原法和~(15)N_2示踪法定量测定其固氮能力,通过基因组DNA的16SrRNA基因序列比对进行鉴定。【结果】在光照培养条件下,采用BG11-N培养基共分离纯化得到自养菌株7株,细胞呈圆形或椭圆形、单列、无分枝、丝状和念珠状,在固体培养基上形成团垫状菌落。新分离菌株在BG11-N培养基中生长状况良好,以基因组DNA为模板可扩增出nifH基因,乙炔还原法和~(15)N_2示踪法测定结果显示具有较高固氮能力,同时具有铁载体生成能力。结合16S rRNA基因序列比对和形态特征,7株菌被初步鉴定隶属于念珠藻科(Nostocaceae)。【结论】从水稻土中分离到在稻田生物固氮中发挥重要作用的蓝细菌(念珠藻科)菌株,可培养固氮蓝细菌菌株固氮能力较高,兼具铁载体生成能力,可作为进一步深入研究的微生物资源,具有潜在的研究应用价值。     

一株红景天内生细菌的筛选及初步研究

【目的】从红景天根部筛选并鉴定一株产酪醇的细菌,初步研究其产酪醇特性,为寻找红景天替代资源提供新途径。【方法】用NA培养基从大花红景天根部中分离内生细菌,通过薄层层析(TLC)、高效液相色谱(HPLC)、气相色谱-质谱联用(GC-MS)筛选出产量最大的菌株,经菌落形态分析、革兰氏染色分析及16S rRNA基因序列分析其分类学地位。单因素实验确定初始pH、培养温度、发酵时间及接种量对菌株产酪醇活力的影响。【结果】从大花红景天根部分离出14株内生细菌,其中8株能产酪醇,筛选出酪醇产量最大的菌株B3,经菌落形态分析、革兰氏染色分析及16S rRNA基因序列分析初步鉴定为水生拉恩氏菌(Rahnella aquatilis)。研究其发酵条件,其最适pH为6.0,最适温度为32 °C,最佳发酵时间为42 h,最佳接种量为15%。在最适发酵条件下,用改良NA培养基发酵,B3菌株酪醇的产量为15.68 mg/L。【结论】B3菌株是一株具有产酪醇能力的细菌,在最适发酵条件下酪醇产量达到15.68 mg/L,具有潜在的开发价值。     

高寒草地珠芽蓼内生拮抗固氮菌Z19的鉴定及其固氮功能

【目的】从东祁连山高寒草地珠芽蓼内生细菌中筛选和鉴定具有固氮能力和拮抗能力的内生细菌。【方法】采用16S rRNA基因序列同源性分析和生理生化指标测定方法对该菌株进行鉴定。【结果】从珠芽蓼中分离获得的21株内生细菌中6株内生菌具有固氮能力,76.2%具有抑菌能力,其中5株内生细菌对5种以上的病原菌有抑制作用;菌株Z19具有较强固氮能力和分解纤维素的能力,其纤维素溶解圈直径与菌落直径比达3.33,产生的纤维素酶活性为0.31 U,且对辣椒立枯丝核病菌(Rhizoctonia solani)、油菜菌核病菌(Sclerotinia sclerotiorum)、番茄灰霉病菌(Botrytis cinerea)、小麦根腐病菌(Bipolaris sorokiniana)和番茄早疫病菌(Alternaria solani)具有较强拮抗能力;经PCR扩增和测序,获得了菌株Z19的固氮基因(nifH)序列和16S rRNA基因序列,在GenBank中的登录号分别为EU693340和EU236746;菌株Z19呈革兰氏阳性,杆状,产芽孢。【结论】结合生理生化特征及16S rRNA基因序列同源性比较,鉴定其为枯草芽孢杆菌(Bacillus subtilis)。     

Enumeration and presumptive identification of some functional groups of bacteria in the rumen of dairy cows fed grass silage-based diets

Abstract Samples of rumen ingesta from two rumen-fistulated dairy cows fed grass silage-based diets were examined for numbers and types of bacteria that developed colonies on rumen fluid-agar media designated to support the growth of (a) a wide range of species, (b) cellulolytic bacteria, (c) lactate-fermenting bacteria, (d) non-fermentative bacteria. The most numerous species was Bacteroides ruminicola followed by Butyrivibrio fibrisolvens . The most abundant cellulolytic species were Eubacterium cellulosolvens and Ruminococcus flavefaciens. Megasphaera elsdenii and Selenomonas ruminantium were important lactate fermenters but an unidentified bacterium that grew poorly on maintenance medium was by far the most numerous among bacteria isolated from lactate-containing medium. One strain remained sufficiently viable to show that it fermented lactate to propionate and acetate.     

Aerobic and anaerobic microbial consumption of hydrogen in geothermal spring water

Abstract Hydrogen consumption was measured in hot geothermal water from two ponds of the San Federigo solfatara, Tuscany, Italy, where emanation gases contained approx. 4% H₂. H₂ consumption was completely inhibited by NaOH and partially by HgCl₂ indicating microbial utilization. Aerobic and anaerobic H₂ consumption activities coexisted in the same water with aerobic activity being higher in one pond and anaerobic activity in the other. The kinetics of H₂ consumption were consistent with those of 'Knallgas', methanogenic or sulfidogenic bacteria.     

解钾菌与解磷菌及固氮菌的相互作用

微生物是土壤肥力的核心 ,土壤中的微生物不仅数量巨大 ,而且种类极多 ,许多微生物对土壤Ｎ ,Ｐ和Ｋ等养分的转化和供给起非常重要的作用。目前 ,研究比较多的主要有解钾菌、解磷菌和固氮菌。能够使土壤中矿物态钾转化为有效形态的细菌 ,目前发现的主要有扭脱芽胞杆菌 (Ｂａｃｉｌｌｕｓｅｘ ｔｏｒｑｕｅｎｓ)、胶质芽胞杆菌 (Ｂ .ｍｕｃｉｌｇｉｎｏｓｎｓ)、环状芽胞杆菌 (Ｂ .ｃｉｒｃｕｌａｎｓ) [1,2 ] 等 ,这些细菌有些同时能使矿物态的Ｐ转化为有效形态。能够使土壤中无效态磷转化为有效态磷的微生物种类也很多 ,研究比较多的是假单…     

Abundance,community structure and diversity of nitrifying bacterial enrichments from low and high saline brackishwater environments

The study reports diversity in nitrifying microbial enrichments from low (0·5–5‰) and high (18–35‰) saline ecosystems. Microbial community profiling of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) enrichments was analysed by sequencing 16S rRNA and was processed using Mothur pipeline. The α-diversity indices showed the richness of nitrifying bacterial consortia from the high saline environment and were clustering based on the source of the sample. AOB and NOB enrichments from both the environments showed diverse lineages of phyla distributed in both groups with 38 and 34 phyla from low saline and 53 and 40 phyla in high saline sources, respectively. At class level, α- and γ-proteobacteria were found to be more dominant in both the enrichments. AOBs and NOBs in enrichments from low saline environments were dominated by Nitrosomonadaceae, Gallionellaceae (Nitrotoga sp.) and Ectothiorhodospiraceae and Nitrospira, respectively. Though Chromatiaceae were present in both AOB and NOB enrichments, Nitrosoglobus and Nitrosococcus dominated the AOBs while NOBs were dominated by uncultured genera, whereas Rhizobiales were found in both the enrichments. AOBs and NOBs in enrichments from high saline environments were dominated by Nitrospira-like AOBs, Nitrosomonas and Nitrosococcus genera, whereas ammonia-oxidizing archaea (AOA) group included Nitrosopumilus and Nitrososphaera genera comprising and Nitrospirae, respectively. The majority of the genera obtained in both the salinities were found to be either uncultured or unclassified groups. Results of the study suggest that the AOB and NOB consortia have unique and diverse microbes in each of the enrichments, capable of functioning in aquaculture systems practised at different salinities (0–60 ppt).     

Detection and characterization of denitrifying bacteria from a permanently ice-covered Antarctic Lake

Denitrifying bacterial strains were isolated from Lake Bonney,apermanently ice-covered and chemically stratified lake in theMcMurdo dry valley region of Antarctica, using complex mediaat4 °C. Three strains, identified as denitrifiers bytheirability to produce nitrous oxide using nitrate or nitrite as arespiratory substrate, were characterized as to theirtemperatureand salinity optima for aerobic growth in batch culture; allthreewere psychrophilic and moderately halophilic. Maximum growthratesof near 0.024 h^–1 were measured for all three strains.Growthrates projected to occur at in situ temperature andsalinityimply generation times on the order of 100 h. Species specificpolyclonal antisera were prepared against two of the strains,ELB17 (from the east lobe of the lake at 17 m) and WLB20 (fromthewest lobe at 20 m). Both strains were subsequently detectedandenumerated in the lake using the antisera. ELB17 was presentinboth lobes below the chemocline, while WLB20 was present inthewest lobe below the chemocline but only in surface waters oftheeast lobe. These distributions are related to the observedchemicaldistributions which imply the occurrence of denitrification inthewest lobe of the lake and not in the east lobe.     

纤维素降解菌的筛选与复合菌系的初步构建

目的针对大庆地区土地盐碱化较严重,盐碱面积较大等现状,从大庆特征性盐碱地区土壤样品中分离出能够降解纤维素的菌株,为降解植物废料以及缓解土壤盐碱化改善土壤环境提供功能菌株。方法通过刚果红染色法初步筛得到具有纤维素降解能力菌株,进一步用比色法测定其纤维素降解率,同时测定菌株耐盐、耐碱、产酸性能,选择性能优良的3株菌作为纤维素降解菌复合菌系构建菌株,通过耐盐性、耐碱性和纤维素降解率实验测定复合菌系菌株最佳组合,进一步通过上述实验确定复合菌系菌株最佳混合比例。结果得到由DX-5和DX-9按照2∶3进行组合复合菌系纤维素降解率最高,达到87.96%,且具有较高的耐盐以及耐碱能力。结论通过实验得到纤维素降解菌的复合菌系,具有较高纤维素降解率以及改善土壤盐碱性能力。     

Characterization of Communities of Heterotrophic Bacteria Associated with Healthy and Diseased Corals in Nha Trang Bay (Vietnam)

A comparative investigation of the heterotrophic microflora of 11 species of healthy corals and of white-band-diseased and yellow-band-diseased corals inhabiting the reefs of Nha Trang Bay (Vietnam), which has been exposed to anthropogenic impact, was performed. Fifty-nine strains of heterotrophic bacteria isolated on Y/K and Endo media were investigated and characterized. All the isolates were identified at the genus level by consideration of the results of analysis of their phenotypic properties, determination of the molar percent of G+C bases in their DNA, and the composition of the fatty acids of lipids. In the composition of the microflora of tissues of healthy corals, γ-proteobacteria prevailed, with halomonads being dominant among them. In addition, the gram-negative bacteria included Pseudomonas and Vibrio spp., members of the Cyto-phaga-Fla-vobacterium-Bacteroides (CFB) phylogenetic cluster, and Moraxella sp. The gram-positive bacteria revealed included Bacillus, Staphylococcus, Halococcus, and Micrococcus spp., and coryneform bacteria. In the composition of the microflora of the tissues of affected corals, bacteria of the family Enterobacteriaceae and of the genera Planococcus and Arthrobacter, which were not revealed in healthy hydrobionts, were found. The anthropogenic impact is not the sole factor determining the infection of corals.