两株四环素降解菌的分离鉴定及降解条件优化

为发掘四环素高效降解菌株,本研究从以四环素为唯一生长碳源的养鸡场粪便堆肥样品中分离筛选到2株四环素降解菌TC-04和TC-09,并通过形态特征、生理生化特征和16SrRNA基因序列分析,对其进行鉴定.采用单因素试验分别探究不同碳源、氮源、微量元素这3个培养基成分和培养时间、接种量和装液量这3个培养条件对两株菌降解四环素...     

甲胺磷降解菌的筛选及降解特性研究

从长期受有机磷农药污染的土壤中分离到1株能降解甲胺磷的菌株B15,经生理生化鉴定为巨大芽孢杆菌(Bacillus megaterium)。在甲胺磷无机盐培养基(甲胺磷浓度为0.5%)生长时,最适生长温度为28℃,最适pH为7.0,摇床培养(28℃190 r/min)48 h降解率达到83%。菌株在甲胺磷浓度为1%的无机盐培养基上能生长,但是在甲胺磷浓度为0.5%的无机盐培养基上生长最好,降解率最高。外加碳氮源对菌株的降解率有所提高,但是超过某一浓度降解率随着浓度的增加反而下降。     

一株乙草胺降解菌的分离及其降解特性研究

【目的】分离获得一株能有效降解乙草胺的菌株,并研究其降解乙草胺的影响因素,为乙草胺生物修复提供微生物资源。【方法】通过富集培养和分离培养,从样品中筛选能以乙草胺为唯一碳氮源的菌株。通过划线培养获得单菌落,并采用革兰氏染色法和16S r RNA基因测序进行菌株的初步鉴定和系统分类。通过单因素试验研究初始乙草胺浓度、外加碳氮源对其降解乙草胺的影响,并基于正交设计进行优化。【结果】分离获得的一株菌为革兰氏阴性菌,初步确定为Pseudomonas sp.,能有效利用乙草胺进行生长。单因素试验证明在乙草胺初始浓度为10 mg/L时降解率最高;外加碳氮源能提高乙草胺降解率,其中葡萄糖和蛋白胨分别最为有效。正交设计表明在最优条件下,其对乙草胺降解率可以达到80.2%。【结论】菌株A-1能有效利用乙草胺进行生长,其降解乙草胺受多种因素影响。本研究将为利用进行该菌株进行乙草胺污染修复提供菌种资源。     

海洋石油降解菌AH07的分离鉴定及其石油降解性能分析

以原油为唯一碳源,从大连新港石油污染区域海底沉积物中分离获得1株石油高效降解菌AH07。通过形态学观察、生理生化特征检验及16S rDNA序列分析,确定菌株AH07为人苍白杆菌(Ochrobactrum anthropi),GenBank序列登录号为KT831449。通过单因素试验确定了菌株AH07的最优生长条件,即培养温度为30℃,培养基pH 7.0。为了进一步了解并提高菌株AH07的降解性能,选用5种氮源考察不同氮源对菌株石油降解性能的影响。结果表明,玉米粉为最佳有机氮源,NH_4NO_3为最佳无机氮源;28℃、150 r/min振荡培养10 d,菌株AH07对原油的降解率分别为58.25%和31.98%。     

一株石油降解菌培养基的优化

目的：有效降低石油降解菌株CT-6在工业生产中的培养成本,提高培养速度。方法：利用Minitab软件,采用中心组合设计、响应面分析,以葡萄糖、蔗糖、可溶性淀粉为碳源,以硝酸铵、尿素、氯化铵为氮源,对高效降解石油菌株CT-6的培养基进行了优化。结果：当碳源葡萄糖为5.6818g/L、氮源氯化铵为3.8030g/L时,菌株CT-6培养17h,OD600达到0.615。结论：优化前后,菌体CT-6的OD600分别为0.289和0.615,提高了112.8%,说明该培养基更有利于菌株CT-6的生长。     

抗草甘膦酵母菌ZM-1的分离鉴定及其生长降解特性

以福州市郊区的耕作土壤为研究材料, 利用草甘膦为选择压力, 通过富集、驯化培养, 分离出一株对草甘膦具有高耐受和降解作用的酵母菌菌株ZM-1, 结合生理生化特征及26S rDNA D1/D2区序列分析将其初步鉴定为胶红酵母菌(Rhodotorula mucilaginosa)。菌株ZM-1能以草甘膦为唯一碳、氮源生长, 对草甘膦的最高耐受浓度为50 g/L。在草甘膦初始浓度为1 g/L的无机盐培养基中, 30°C、150 r/min 摇床振荡培养7 d, 草甘膦降解率为85.38%。适合菌株ZM-1生长及降解草甘膦的最佳条件为: 草甘膦初始浓度1 g/L, 接种量4%, 温度30°C, pH 值5.5-6.0, 装料量50 mL/250 mL。菌株ZM-1是一株良好的草甘膦耐受菌, 可用于草甘膦污染环境的生物修复, 也可能成为转基因抗草甘膦作物的一个很好资源。     

苯胺降解菌的筛选、降解特性及其发酵优化

【背景】近年来,苯胺类化合物加重了生态环境的污染,而生物法处理苯胺类废水具有较大发展潜力与广阔的应用前景。【目的】从长期受苯胺类化合物污染的活性污泥中分离获得一株能高效降解苯胺的菌株,优化其培养基及降解条件,为苯胺生物修复提供菌株与基因资源。【方法】采用平板法从富集驯化的菌株中筛选出以苯胺为唯一碳氮源和能源的高效降解菌,通过16S rRNA基因测序鉴定菌种,利用单因素筛选实验对降解条件进行优化,通过正交试验优化培养条件。【结果】筛选到一株苯胺降解菌BA-6,经鉴定为微杆菌属(Microbacterium)。菌株BA-6对初始浓度为600mg/L苯胺的日降解率可达98%以上。其高效降解的温度范围是30–37℃,pH范围是6.5–7.5。底物利用实验表明,菌株BA-6具有降解多种苯胺类化合物的能力。发酵培养基优化实验获得一种发酵培养基,活菌量高达3.06×10¹⁰CFU/mL。【结论】苯胺降解菌BA-6对苯胺有较强的降解能力和环境调节能力,在修复苯胺类化合物的生态污染方面有一定的应用前景。     

制革废水中壬基酚聚氧乙烯醚降解菌的分离及特性

从长期受壬基酚聚氧乙烯醚污染的制革废水中采集水样,通过富集培养的方法从中筛选到一株可以壬基酚聚氧乙烯醚为唯一碳源生长的降解菌OPQa3。通过形态学特征观察和生理生化试验,结合16S rRNA基因序列分析,初步鉴定菌株OPQa3属于短波单胞菌属Brevundimonas sp.,其16S rRNA基因序列与Brevundimonas diminuta(EU434566.1)的相似性最高(99%)。降解菌OPQa3的生长周期为24 h;以2%的量接种菌株OPQa3,保证最终OD600=0.70,于746 mg/L的壬基酚聚氧乙烯醚培养基中,120 h内的降解率可达84.5%,菌OPQa3生长的最佳温度为30°C,最适pH值在7左右。降解性质粒检测结果表明,控制菌株OPQa3降解壬基酚聚氧乙烯醚的基因位于质粒上。     

苯酚降解菌ZJ-1的分离及降解特性研究

目的:筛选苯酚降解菌,用于降解苯酚提高氧化塘处理效率.方法:以苯酚为惟一碳源进行选择性培养.结果:从乌鲁木齐市某炼油厂污水池的活性污泥中分离出一株能以苯酚为惟一碳源培养基上生长的菌株,编号为ZJ-1,该菌株最高可耐受1000mg/L的苯酚.对该苯酚降解菌降解性能研究表明:该菌具有较强的降解能力,在32℃、pH 7左右、接种量1%时,摇床振荡速度120r/min的条件下,该菌株在48h内苯酚降解率可达81%以上.培养液中苯酚浓度在300mg/L、500mg/L时,该菌株的降解率比较明显.当苯酚浓度大于1000mg/L时,则元明显降解效果.结论:ZJ-1菌株对苯酚具有较强的降解能力,具有广阔的应用前景.     

1株聚乙烯醇降解菌的分离鉴定及其降解性能

筛选聚乙烯醇（PVA）降解性能优良且适合驯化的菌种是PVA生物降解的关键环节。为了获取PVA高效降解菌种,采用选择性培养基从某化工厂回流池污泥中筛选菌株,并对菌株的生长及PVA降解过程、培养液pH值、温度、摇床转速、装液量进行测定。结果表明：筛选的1株聚乙烯醇高效降解菌MH 007,基于16S rRNA基因序列的系统发育多样性分析鉴定该菌为Sphingopyxis terrae的一个菌株。该菌PVA降解率可达97.2%,摇床动态培养过程中降解PVA的最佳条件为pH 7.2、温度30 ℃、摇床转速120 r/min和30%的装样量。     

Effect of nutrition of Monascus sp. on formation of red pigments

Summary A higher producer of ascospores and pigments, Monascus strain TTWMB 6042, was used to study regulation of pigment production by nutrients. An initial medium containing 4% glucose, 0.3% NH₄NO₃ (75 mm nitrogen) and inorganic salts was used. We found that the formation of red pigments in this strain, measured by optical density at 500 nm (OD₅₀₀) was strongly stimulated by monosodium glutamate (MSG) as the sole nitrogen source. The choice of carbon source and an initial pH of pH 5.5 were also important. High concentrations of phosphate and MgSO₄ were inhibitory to pigment production. A new chemically defined medium was devised containing 5% maltose, 75 mm MSG, phosphate and MgSO₄ at lower concentrations plus other mineral salts, which yielded a tenfold increase in OD₅₀₀ and a reversal of the pigment location from predominantly cell-bound, including both intracellular and surface-bound pigments, to mainly extracellular. Offsprint requests to: A. L. Demain     

High-level production of heterologous proteins using untreated cane molasses and corn steep liquor in Escherichia coli medium

To develop an economical industrial medium, untreated cane molasses (UCM) was tested as a carbon source for fermentation culturing of Escherichia coli. To test the industrial application of this medium, we chose a strain co-expressing a carbonyl reductase (PsCR) and a glucose dehydrogenase (BmGDH). Although corn steep liquor (CSL) could be used as an inexpensive nitrogen source to replace peptone, yeast extract could not be replaced in E. coli media. In a volume of 40 ml per 1-l flask, a cell concentration of optical density (OD₆₀₀) 15.1 and enzyme activities of 6.51 U/ml PsCR and 3.32 U/ml BmGDH were obtained in an optimized medium containing 25.66 g/l yeast extract, 3.88 g/l UCM, and 7.1% (v/v) CSL. When 3.88 g/l UCM was added to the medium at 6 h in a fed-batch process, the E. coli concentration increased to OD₆₀₀ of 24, and expression of both PsCR and BmGDH were twofold higher than that of a batch process. Recombinant cells from batch or fed-batch cultures were assayed for recombinant enzyme activity by testing the reduction of ethyl 4-chloro-3-oxobutanoate to ethyl (S)-4-chloro-3-hydroxybutanoate (CHBE). Compared to cells from batch cultures, fed-batch cultured cells showed higher recombinant enzyme expression, producing 560 mM CHBE in the organic phase with a molar yield of 92% and an optical purity of the (S)-isomer of >99% enantiomeric excess.     

Biodegradation of methidathion by Serratia sp. in pure cultures using an orthogonal experiment design, and its application in detoxification of the insecticide on crops

An enrichment culture method was applied to the isolation of a bacterial strain responsible for biodegradation of methidathion residues, from a methidathion-treated orchard. The strain (SPL-2) was identified as Serratia sp. according to its physiological characteristics and 16S rRNA gene phylogenetic analysis. Serratia sp. was able to grow in a poor medium consisting of mineral salts and using methidathion as the sole carbon source at a concentrations of 50–150 mg/L. The effects of multifactors on degradation of methidathion in pure cultures by Serratia sp. were investigated using an orthogonal experimental design L₉ (3⁴). On the basis of range analysis and ANOVA results, the most significant factors were temperature and inoculum size. The optimal conditions for methidathion biodegradation in pure cultures were a temperature in 30 °C, an inoculum size of 10 %, pH?=?7 and an aeration rate of 200 rpm. Two different concentrations of strain SPL-2 fermenting liquids (OD₆₀₀?=?0.2 and OD₆₀₀?=?0.4) were prepared and applied to remove methidathion residues from agricultural products, and this process can be described by a first order rate model. In contrast to controls, the DT₅₀ of methidathion was shortened by 35.7 %, 8.2 % and by 62.3 %, 57.5 % on OD₆₀₀?=?0.2 and OD₆₀₀?=?0.4 treated haricot beans and peaches, respectively. These results suggest that the isolated bacterial strain may have potential for use in bioremediation of methidathion-contaminated crops.     

响应面法优化杀鱼假交替单胞菌2515发酵培养基

杀鱼假交替单胞菌(Pseudoalteromonas piscicida)2515是一株具有广谱抗弧菌性能的菌株，为提升菌株2515的培养生物量，通过单因素优化方法，研究碳源、氮源、无机盐等营养成分对菌株2515的发酵产量的影响，确定关键营养因子，利用响应面分析法对影响菌株2515生物量的关键营养因子进行优化。结果显示，菌株2515的最佳发酵培养基配方为麦芽糖2.85 g/L、CaCl₂ 0.65 g/L、MnCl₂ 0.10 g/L、酵母膏3.85 g/L、胰蛋白胨10 g/L、NaCl 10 g/L。优化后的培养基使菌株2515在锥形瓶和发酵罐中发酵的OD₆₀₀值分别为1.416和1.866,生物量分别提高了36.4%和40.4%,其发酵上清液和细胞内容物的抑菌活性分别提高了28.2%和27.2%。表明响应面法优化后的培养基有利于提高菌株2515的发酵生物量及抗菌效果，研究结果为菌株2515的后续开发应用提供了参考。     

Microbial degradation of cyanide and thiocyanate

The role played by a bacterial community composed ofPseudomonas putida, strain 21;Pseudomonas stutzeri, strain 18; andPseudomonas sp., strain 5, and by physical and chemical factors in the degradation of CN⁻ and SCN⁻ was studied. It was shown that the degradation of CN⁻ is determined both by the action of bacteria and by abiotic physical and chemical factors (pH, O₂, temperature, the medium agitation rate, etc.). The contribution of chemical degradation was found to increase drastically at pH below 9.0; when air was blown through the medium (irrespective of the pH value); under active agitation of the medium; and when the medium surface interfacing air was increased. Even at elevated pH values (9.0-9.2), suboptimal for bacterial growth, the microbial degradation could account for at most 20–25 mg/1 of CN⁻, regardless of its initial concentration. When CN⁻ and SCN⁻ were concurrently present in the medium, the former compound was the first to be degraded by microorganisms. The rate of bacterial degradation of SCN⁻ under continuous cultivation in a chain of reactors was found to depend on its concentration, the medium flow rate, agitation rate, and the pattern of carbon source supply and could exceed 1 g/(l day). CN⁻ and SCN⁻ are utilized by bacteria solely as nitrogen sources. The mechanism of CN⁻ and SCN⁻ degradation by the microbial community is discussed. Deceased.     

Production and Characterization of an Exopolysaccharide by Yeast

Antarctic yeast strains were investigated for exopolysaccharide biosynthesis and the Sporobolomyces salmonicolor AL₁ strain was selected. It was studied for exopolysaccharide biosynthesis on different carbon and nitrogen sources. The investigations showed that sucrose and ammonium sulphate were suitable culture medium components for polymer biosynthesis. Exopolysaccharide formation by the yeast strain was accompanied by a decrease in the culture medium pH value from the initial pH 5.3 to pH 1.7–2.0. During the biosynthetic process, the dynamic viscosity of the culture broth increased to the maximum value of 15.37 mPas and the polysaccharide yield reached 5.63 g/l on a culture medium containing 5.00% sucrose and 0.25% ammonium sulphate at a temperature of 22 °C for 120 h. The crude polysaccharide obtained from Sp. salmonicolor AL₁ featured high purity (90.16% of carbon content) and consisted of glucose (54.1%), mannose (42.6%) and fucose (3.3%). Pure mannan containing 98.6% of mannose was isolated from it.     

Effect of culture medium composition on the activity of extracellular lectins of <Emphasis Type="Italic">Lentinus edodes</Emphasis>

The time course of lectin production in culture liquid of the basidial fungus Lentinus edodes strain F-249 in different media under submerged culture conditions was studied. The activity of agglutinins depended on the ratio between carbon and nitrogen sources and the pH of the culture medium. The lectin activity in culture medium was maximal when the fungus was grown in a medium containing L-arabinose as a source of carbon and L-asparagine as a source of nitrogen (C:N ratio, (9.5–12):1) on day 15–18 of culturing at pH 8.0–9.0.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 2, 2005, pp. 200–203.Original Russian Text Copyright © 2005 by Tsivileva, Nikitina, Garibova.     

Isolation and Culture Conditions of Thermophilic Hydrogen Bacteria

Isolation of thermophilic hydrogen bacteria was performed at 50°C using enrichment culture method. One of the four strains isolated, strain TH-1 grew most rapidly. Culture conditions of strain TH-1 were investigated. Optimum temperature and pH for growth proved to be 52°C and 7.0, respectively. There existed a positive correlation between the specific growth rate and the partial pressure of carbon dioxide in the gas phase. Ammonium and nitrate are the good nitrogen sources in that order. Effect of concentrations of nitrogen source, magnesium, ferrous and phosphate ions on the cell growth was also investigated. The maximum specific growth rate (μ_max) of strain TH-1 was determined as 0.68 hr^?1 by the cultivation at 52°C in a jar fermentor containing the optimal medium at pH 7.0.     

Decolorization of a dye industry effluent by <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis> XC6

The strain Aspergillus fumigatus XC6 isolated from mildewing rice straw was evaluated for its ability to decolorize a dye industry effluent. The strain was capable of decolorizing dyes effluent over a pH range 3.0–8.0 with the dyes as sole carbon and nitrogen sources. The optimum pH was 3.0; however, supplemented with either appropriate nitrogen sources (0.2% NH₄Cl or (NH₄)₂SO₄ ) or carbon sources (1.0% sucrose or potato starch), the strain decolorized the effluent completely at the original pH of the dyes effluent. Therefore, A. fumigatus XC6 is an efficient strain for the decolorization of reactive textile dyes effluents, and it might be a practical alternative in dyeing wastewater treatment.