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【目的】筛选能够利用甲醇的微生物菌株,并将其应用于甲醇测定的初步研究中。【方法】采用富集培养及固体平板分离法分离菌株;通过生理生化特征及16S rDNA序列分析进行菌株鉴定;以固定化细胞和溶氧仪组合成测定系统,测定了不同含量甲醇的响应时间以及溶氧变化与甲醇含量的关系。【结果】从山西清徐农用沼气池中分离得到一株能以甲醇为唯一碳源和能源生长的菌株M211,通过生理生化特征及16SrDNA序列分析,该菌株被鉴定为嗜有机甲基杆菌(Methylobacterium organophilium)。传感系统在0.02%-1%(V/V)甲醇含量范围内测定,响应时间小于20 min,检出限为0.27 mg/L,溶氧消耗量同甲醇含量呈线性关系,拟合系数(R2)为0.9986。该测定体系不易受其它干扰物质影响,检测结果与实际样品浓度一致。【结论】该测定体系具有较强的选择性,及良好的重现性和稳定性,具有较好的应用前景。 相似文献
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甲醇和甲烷等一碳原料来源广泛,价格低廉,是生物制造的理想原料。甲醇脱氢酶(Methanol dehydrogenase,MDH)催化甲醇生成甲醛是一碳代谢的关键反应。目前已从天然甲基营养菌中发现了多种利用不同辅因子,具有不同酶学性质的MDH。其中,烟酰胺腺嘌呤双核苷酸(NAD)依赖型MDH被广泛应用于构建人工甲基营养菌。但是,NAD依赖型MDH的甲醇氧化活性较低,对甲醇的亲和力较差,导致甲醇氧化成为人工甲基营养菌代谢甲醇的限速步骤。为了提高甲醇氧化速率,进而提高人工甲基营养菌的甲醇利用效率,近年来大量研究集中于MDH的挖掘与改造研究。文中系统综述了不同类型MDH的发现、表征、改造以及在人工甲基营养菌中的应用进展,详细阐述了MDH的定向进化和多酶复合体的构建,并展望了通过细胞生长偶联的蛋白质进化和蛋白质理性设计获得高活性MDH的潜在策略。 相似文献
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Effects of methanol on expression of an anticoagulant hirudin in recombinant Hansenula polymorpha 总被引:1,自引:0,他引:1
A series of batch, fed-batch, and continuous cultures was carried out to analyze the effects of methanol on the fermentation
characteristics of recombinant Hansenula polymorpha for the production of hirudin, an anticoagulant. Hirudin expression efficiencies were greatly influenced by the methanol
concentrations in continuous and fed-batch culture modes. At a steady state of continuous culture, an optimum methanol concentration
of 1.7 g l−1 was determined at a dilution rate of 0.18 h−1 with 1.8 mg l−1 h−1 hirudin productivity. Journal of Industrial Microbiology & Biotechnology (2001) 27, 58–61.
Received 21 September 2000/ Accepted in revised form 10 June 2001 相似文献
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Global metabolite analysis: the influence of extraction methodology on metabolome profiles of Escherichia coli 总被引:4,自引:0,他引:4
The global pool of all metabolites in a cell, or metabolome, is a reflection of all the metabolic functions of an organism under any particular growth condition. In the absence of in situ methods capable of universally measuring metabolite pools, intracellular metabolite measurements need to be performed in vitro after extraction. In the past, a variety of cell lysis methods were adopted for assays of individual metabolites or groups of intermediates in pathways. In this study, metabolites were extracted from Escherichia coli using six different commonly used procedures including acid or alkaline treatments, permeabilization by freezing with methanol, high-temperature extraction in the presence of ethanol or methanol, and by lysis with chloroform-methanol. Metabolites were extracted by the six methods from cells grown under identical conditions and labeled with [14C]glucose. The metabolomes were compared after 2-dimensional thin-layer chromatography of labeled compounds. For global analysis, extraction with cold (-40 degrees C) methanol showed the greatest promise, allowing simultaneous resolution of more than 95 metabolite spots. In contrast, 80 or less spots were obtained with other extraction methods. Extraction also influenced quantitative analysis of particular compounds. Metabolites such as adenosine exhibited up to 20-fold higher abundance after cold methanol extraction than after extraction with acid, alkali, or chloroform. The simplicity, rapidity, and universality of cold methanol extraction offer great promise if a single method of lysis is to be adopted in metabolome analysis. 相似文献
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一株高效处理甲醇废水细菌的研究 总被引:3,自引:0,他引:3
采用富集培养法从土壤中分离出 1株净化甲醇能力较强的菌株 ,经鉴定为假单胞菌属 (Pseudomonas.sp)编号为 186。该菌株能以甲醇作为唯一碳源和能源 ,在培养 38h的条件下 ,可以使废水中的甲醇净化 90 %以上。同时对该菌的形态、生理特征进行了研究。 相似文献
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Abstract The monomethyl sulfate-degrading bacterium, Hyphomicrobium MS 223 , contains a NAD(P)-independent methanol dehydrogenase (EC 1.1.99.8) which was isolated and characterized. The enzyme was activated by ammonium ions, had an M r of 118000 and was composed of two subunits of identical M r . It showed a broad substrate specificity for primary alcohols and was able to oxidize secondary alcohols and several aliphatic aldehydes. The new competitive inhibitor acetaldehyde oxime inhibited aldehyde oxidation more strongly than alcohol oxidation. 相似文献
9.
A methanol sensor was developed with response time less than 2 min. It was unaffected by the dissolved O2 concentration, agitation speed or pH value. When the sensor was used to monitor the methanol concentration on-line during hirudin production by recombinant Pichia pastoris, the cell dry weight was up to 155 g l–1, and hirudin was 1.4 g l–1. 相似文献
10.
MxaJ structure reveals a periplasmic binding protein‐like architecture with unique secondary structural elements
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MxaJ is a component of type II methanol dehydrogenase (MDH) that mediates electron transfer during methanol oxidation in methanotrophic bacteria. However, little is known about how MxaJ structurally cooperates with MDH and Cytochrome cL. Here, we report for the first time the crystal structure of MxaJ. MxaJ consists of eight α‐helices and six β‐strands, and resembles the “bi‐lobate” folding architecture found in periplasmic binding proteins. Distinctive features of MxaJ include prominent loops and a β‐strand around the hinge region supporting the ligand‐binding cavity, which might provide a more favorable framework for interacting with proteins rather than small molecules. Proteins 2017; 85:1379–1386. © 2017 Wiley Periodicals, Inc. 相似文献
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Thomas J. Lyimo Arjan Pol Mike S. M. Jetten & Huub J. M. Op den Camp 《FEMS microbiology letters》2009,291(2):247-253
Mangrove forest sediments produce significant amounts of methane, but the diversity of methanogenic archaea is not well known at present. Therefore, 16S rRNA gene libraries were made using archaea-specific primers and DNA extracted directly from Tanzanian mangrove sediment samples as a template. Analysis of sequence data showed phylotypes closely related to cultivated methylotrophic methanogenic archaea from the marine environment, or distantly related to acetoclastic and hydrogenotrophic methanogenic archaea. In an attempt to isolate relevant methanogenic archaea, we succeeded in obtaining a new mesophilic methylotrophic methanogenic archaeon (strain MM1) capable of utilizing methanol and methylated amines as the only substrates. Under optimum conditions, the cells of strain MM1 exhibited a high specific growth rate (μ) of 0.21±0.03 (i.e. doubling time of 3.2 h) on both methanol and trimethylamine. The 16S rRNA gene sequence of strain MM1 clustered with five environmental clones, indicating that MM1 is an important methanogenic methylotroph in mangrove sediments. Based on physiological and phylogenetic analyses, strain MM1 is proposed to be included in the species of Methanococcoides methylutens . 相似文献
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Dr. K. Hans Wurzinger Joseph E. Novotny Harvey W. Mohrenweiser 《Molecular and cellular biochemistry》1985,66(2):127-136
Summary The activity of the human erythrocyte acid phosphatase is modulated by a series of structural analogs of purine. The unsubstituted purine base does not affect the enzyme activity. Addition of a substituent at the number six position usually generates an analog which activates the enzyme while similar substitutions at the two position usually generate an inhibitor. Pyrimidines are generally ineffective as modulators while several modifications of the imidazole ring of the purine analogs do not abolish the modulator activity of the purine analog. The level of response to all active analogs is isozyme specific. Differences in apparent relative affinities among the modulators are noted. The modulators with a positive effect on enzyme activity, are effective in the presence of methanol which is more effective than H20 as a phosphate acceptor. These analogs act by enhancing the rate of transfer of phosphate to H2O, while decreasing the rate of transfer to methanol. The results suggest that the purine analogs may act by altering the rate of hydrolysis of the phosphoenzyme intermediate by H20 or may change the rate-limiting step in the catalytic mechanism. 相似文献
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Abstract A study was made of the enzymology of primary and intermediary pathways of C1 metabolism in three strains of non-motile obligately methylotrophic bacteria. Each uses a variant of the ribulosemonophosphate (RMP) cycle of formaldehyde fixation which involves the Entner-Doudoroff route for hexose-phosphate cleavage and transaldolase/transketolase mode of rearrangement. The organisms possess high levels of hexulose-phosphate synthase and NAD(P)-linked glucose-6-phosphate and 6-phosphogluconate dehydrogenases. In addition they contain small activities of dye-linked methanol and methylamine dehydrogenases, PMS- and NAD-linked formaldehyde and formate dehydrogenases. This indicates cyclic rather than direct oxidation of formaldehyde derived from methanol or methylamine. The tricarboxylic acid cycle is defective in 2-ketoglutarate dehydrogenase and the glyoxylate shunt is not operating because of the absence of malate synthase. Oxaloacetate is regenerated by (phosphoenol) pyruvate carboxylases. NH+ 4 is assimilated mainly by glutamate dehydrogenase. The results show metabolic similarities between motile and non-motile obligate methanol and methylamine utilizers. 相似文献
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用GC-MS对大豆胚芽脱脂后的甲醇萃取物进行了分析.结果表明,所得甲醇萃取物的主要成分是脂肪酸及其酯,其中不饱和脂肪酸酯的含量较高.此外,还检测出少量长链烷烃. 相似文献
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R. Bhaskara Rao K. Anupama K.R.L. Anand Swaroop T. Murugesan M. Pal S.C. Mandal 《Phytomedicine》2002,9(8):731-733
A study was carried out to evaluate the anti-pyretic effect of a methanol extract of stem bark of Ficus racemosa Linn. (MEFR) on normal body temperature and yeast-induced pyrexia in albino rats. A yeast suspension (10 ml/kg body wt.) increased rectal temperature 19 h after subcutaneous injection. The MEFR, at doses of 100, 200 and 300 mg/kg body wt. p.o., showed significant dose-dependent reduction in normal body temperature and yeast-provoked elevated temperature. The effect extended up to 5 h after drug administration. The anti-pyretic effect of MEFR was comparable to that of paracetamol (150 mg/kg body wt., p.o.), a standard anti-pyretic agent. 相似文献
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Van T. Nguyen Phuong T.M. Nguyen Donghai Mei Collin D. Wick Duong D. Do 《Molecular simulation》2014,40(14):1113-1124
Grand canonical Monte Carlo simulations were carried out to study the equilibrium adsorption concentration of methanol and water in all-silica BEA zeolite and HBEA zeolites with different Si/Al ratios over a wide range of temperatures and loadings. These zeolites have oval-shaped channels with one side longer than the other. Water sorption into the hydrophobic BEA zeolite had a sharp transition with its sorption going from zero to near full capacity over a very small pressure range. Methanol sorption was much more gradual with respect to pressure. With the addition of hydrophilic sites for the HBEA zeolites by decreasing the Si/Al ratio, adsorption at lower pressures increased significantly for water and methanol. At higher loadings, water and methanol adsorption were found to behave in fundamentally different ways. Water structures in the zeolite channels formed hydrogen-bonded chains while maximising contact with the surfaces on the longer edges of the zeolite channels. Methanol molecules, in contrast, formed very few hydrogen bonds between themselves, with their hydroxyl groups primarily binding with surface of the shorter edge of the zeolite channels and their methyl groups located near the middle of the zeolite channels. The addition of hydrophilic groups in the HBEA zeolites strongly influenced positions of the methanol hydroxyl groups at high loadings, but did not have a significant effect on water structure. 相似文献
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大量研究表明施用甲醇能够促进多种植物的生长,在甲醇刺激植物生长的机理中,支持碳源假说的证据最多。该研究通过考察矮牵牛甲醇代谢与甲醇刺激其生长的相关性,对碳源假说进行验证。结果表明:(1)在MS固体培养基上添加2和6mmol/L CH3OH均可促进矮牵牛的生长和叶绿素含量增加,但2mmol/L CH3OH(低浓度)效果好于6mmol/L(高浓度),而且添加6mmol/L CH3OH会诱发较强的氧化胁迫。(2)进一步用13 C-NMR分析矮牵牛对不同浓度13 CH3OH的代谢作用发现,6mmol/L 13 CH3OH处理矮牵牛中[U-13 C]Fruc和[U-13 C]Gluc的生成量显著大于2mmol/L 13 CH3OH处理,即来自甲醇的碳源在代谢过程中虽被卡尔文循环同化为糖类物质,但这部分碳源对甲醇刺激矮牵牛的生长贡献不大。这些证据表明CH3OH代谢与其刺激矮牵牛生长的效果没有关联性,该实验结果不支持碳源假说。 相似文献
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Purpose. To evaluate the outcome of corneal transplantation and the feasibility of tissue donation from donors with methanol intoxication.
Methods. Four corneas from two methanol intoxication victims were procured and transplanted in four patients at our medical center. The outcome and graft survival were evaluated.
Results. The recipients were between 12 and 49 years of age. Indications for transplantation were keratoconus (two patients), post-traumatic corneal perforation (one patient) and alkaline burn (one patient). The follow-up period ranged between 12 and 60 months. All grafts remained clear, and the postoperative visual acuity was 20/30 in keratoconus patients and 20/60 in others.
Conclusions. The methanol intoxication victims appear to be suitable donors for corneal transplantation. To the best of our knowledge, this is the first study to report successful corneal transplantation from donors with methanol intoxication. 相似文献