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厦门沿岸海域杂色鲍中产琼胶酶菌株的筛选及其酶学性质的研究 总被引：1，自引：0，他引：1
琼胶酶在食品工业中的多糖降解中有着重要的作用,其经济价值日益凸显,从海洋生物中筛选琼胶酶菌株是获得琼胶酶的一种重要途径.从厦门沿岸海域养殖杂色鲍鱼体内分离得到5株产高效琼胶酶的菌株,其中最高的酶活力达到133.5 U/dm3.经16S rRNA序列分析表明这5株菌株分别属于弧菌属（Vibrio）和假交替单胞菌属（Pseudoa lteromonas）.采用DNS法对这些菌株所产的琼胶酶进行酶学性质研究,结果显示这些酶的最适作用温度均为50℃,最适作用pH值为7.0;Na＋可使A017菌株所产的琼胶酶酶活力提高5倍,Fe2＋对A007、A008、A010、A021菌株所产的琼胶酶酶活力有明显的抑制作用. 相似文献
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海洋细菌QY202产κ-卡拉胶酶的分离纯化和性质研究 总被引：1，自引：0，他引：1
为获得高效降解卡拉胶菌株,从青岛太平角海域采集的角叉菜表面分离到1株高产κ-卡拉胶酶的海洋交替假单胞菌(Pseudoalteromonas sp.)QY202,经硫酸铵沉淀、脱盐、DEAE阴离子交换层析等步骤从该菌株发酵液上清中分离纯化得到1种专一性降解κ-卡拉胶的κ-卡拉胶酶,并研究了该酶的基本酶学性质.结果表明该酶被纯化了23.1倍,回收率为43.9%,分子量大小为33.2 kDa.酶的最适反应温度为40 ℃,最适反应pH为8.0,在0～40 ℃,pH=7.0～8.0之间酶活力较稳定.酶对底物κ-卡拉胶的米氏常数Km值为1.6 mg/mL.Na~+、K~+对酶活有促进作用,而Hg~(2+)、Cu~(2+)强烈抑制酶的活性.酶解κ-卡拉胶的主产物为硫酸新κ-卡拉二糖和硫酸新κ-卡拉四糖. 相似文献
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从一株海洋假单胞菌中分离制备出一种具有纤溶活性的酶 ,对其酶学性质进行实验研究结果显示 :该酶的分子量是 2 1k D,等电点是 7.4～ 7.5 ;最适作用 p H是 8.0 ,最适作用温度是 5 0℃。该酶具有降解苯甲酰 - L -精氨酸乙酯盐酸盐 (BAEE)的活性 ,酶的动力学分析表明 :Km =0 .87mmol/ L,Vmax=1.80× 10 -3 mmol/ L s-1。 相似文献
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以印尼热泉菌为材料,采用以褐藻酸钠为唯一碳源的培养基筛选产褐藻胶裂解酶的菌株,通过16S rDNA序列对产酶菌株进行种属鉴定,并通过硫酸铵沉淀、离子交换层析和凝胶过滤层析从高产酶菌株Aly-B5发酵液上清中纯化获得褐藻胶裂解酶,并对该酶的酶学性质进行了研究。结果表明:高产酶菌株经鉴定为Bacillus属;聚丙烯酰胺凝胶电泳(Sodium dodecyl sulfate polyacrylamide gel electrophoresis,SDS-PAGE)显示纯化的褐藻胶裂解酶Aly-B5分子量为45kDa,该酶最适作用温度为65°C,75°C时的半衰期为110min,最适pH为7.0;Zn~(2+)、Mg~(2+)、Fe~(2+)对酶活具有明显的抑制作用,但该酶对乙二胺四乙酸(ethylene diamine tetraacetic acid,EDTA)并不敏感;同时,底物特异性实验表明Aly-B5是一种偏好降解聚古罗糖醛酸(poly G)的双功能裂解酶,降解产物主要是二糖。该酶优良的耐热性使其在海藻高值化利用领域具有潜在的应用前景。 相似文献
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从微泡菌属AG1（Microbulbifer sp. AG1）克隆得到1302 bp大小的琼胶酶基因,该基因编码产物为一个成熟蛋白（413个氨基酸残基）外加一个信号肽（20个残基）。将不含信号肽片段的琼胶酶在E. coli BL21 （DE3）中进行了异源表达和纯化。使用琼脂糖作为底物,该重组琼胶酶的最适反应温度和pH分别为60℃和7.5。该重组酶表现出优良的热稳定性,在50℃和60℃下处理1 h,重组琼胶酶仍能分别保持67%和19%的残余酶活力。除了SDS,重组琼胶酶对于其他测试的抑制剂、去垢剂和尿素变性剂有着较好的抗性。利用薄层色谱和以对硝基苯-α/β-D-吡喃半乳糖苷为底物的酶活力分析结果表明,该重组琼胶酶为β型琼胶酶,它水解琼脂糖的主要终产物为新琼四糖,而且不同聚合度的酶解产物具有抗氧化活性。 相似文献
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从大型褐藻藻体分离获得一株具有高效降解琼胶和褐藻胶能力的革兰氏阴性菌菌株ST-6。16S rDNA序列分析结果表明,该菌株与海绵假单胞菌的相似度达到99%,NJ法构建系统进化树也与海绵假单胞菌归为一类,鉴定为海绵假单胞菌Pseudomonas pachastrellae ST-6。在2216E培养基、30℃培养条件下,海绵假单胞菌ST-6的生长曲线表明,接种10~48 h为菌株的指数生长期,48~72 h为生长稳定期。产酶结果表明,菌株ST-6在指数生长期时菌液的胞外琼胶酶相对酶活力较高,在接种48 h时,菌液的琼胶酶相对酶活力最高为249.15 U/m L。此外,发现菌株ST-6的琼胶酶和褐藻胶酶的分泌类型分别为非诱导型和诱导型。采用单因素分析法对其生长和产酶条件进行分析,结果表明,海绵假单胞菌ST-6最适生长条件为:温度25~35℃,33值5~9;最适产琼胶酶条件为:温度30℃,33值为7,琼胶浓度0.3%。最适产褐藻胶酶条件为:温度35℃,33值为9。在温度30℃、339和褐藻酸钠浓度0.15%的培养条件下,海绵假单胞菌ST-6获得最高胞外褐藻胶酶相对酶活力为135.54 U/m L。 相似文献
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芳基硫酸酯酶具有断裂硫酸酯键的功能,并可应用于酶法脱除琼胶上的硫酸基,提高凝胶强度,改善琼胶性能.为了发掘能用于琼胶脱硫的新型芳基硫酸酯酶,本研究根据嗜琼胶华美菌(Formosa agariphila)KMM 3901的基因组注释信息,筛选出了一段芳基硫酸酯酶编码序列OUC-FARS6,并在大肠杆菌中对其进行异源表达,研究该酶的酶学性质,初步探究其在琼胶脱硫中的作用.研究表明,该酶的分子量大小为63 kDa,以对硝基苯硫酸酯(pNPS)为底物反应90 min时的最适温度为45℃,最适pH为9.0.Na+和K+对酶活有促进作用,大部分金属离子、SDS和Na2 EDTA都可抑制该酶酶活.动力学结果显示,该酶的Km值为32.63μmol/L,Vmax值为9.25μmol/(L·min).将琼胶与该芳基硫酸酯酶共同孵育后,琼胶内部空隙变小,呈现出较好的空间网状结构.本研究成功发掘了一个新型芳基硫酸酯酶,该酶具有应用于琼胶脱硫的潜力,同时建立了利用该酶进行琼胶脱硫的催化体系. 相似文献
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产甲壳素酶菌株HD001的发酵条件研究及酶的分离纯化 总被引：1，自引：0，他引：1
通过对降解甲壳素菌株 HD001 的发酵条件研究,确定了其产甲壳素酶最适培养基组分为 ( w/v ):( NH4 ) 2SO4 2.0%, NaCl 0.5%, K2HPO4 0.07%, KH2P O4 0.03%, MgSO4·7H2O 0.05% 以及葡萄糖 0.1%、酵母粉 0.3% 和胶体甲壳素 1.5%;最适产酶培养条件为:培养基起始 pH 值 6.0,培养温度 30 ℃,培养时间 120 h,发酵液酶活力达 376.2 U/mL.采用硫酸铵分级盐析、DEAE-纤维素离子交换层析、Sephacryl S-100 凝胶过滤层析对该酶进行纯化后,SDS-PAGE电泳显示单一条带,其相对分子质量约为 85.7 kDa. 相似文献
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海洋弧菌QJH-12发酵产琼胶酶条件的优化 总被引：1，自引：0，他引：1
从中国南海海域分离到了一株具有较高琼胶降解活性的弧菌Vibrio sp.QJH-12,该菌株为革兰氏阴性菌,呈弯曲杆状,极生单根鞭毛,氧化酶阳性,过氧化氢酶阳性,O/129试验阳性。在琼胶平板上生长可软化琼胶,并在菌落周围产生凹陷。通过单因子实验和正交实验确定了培养基的最佳组成:琼胶2.0‰,柠檬酸三铵1.0‰,K2HPO41.0‰,NaCl1.0%。确定该菌株的最适发酵产酶条件:装液量为250mL的三角瓶中装入125mL的液体发酵培养基,培养基起始pH6.5,摇瓶转速150r/min,30℃发酵培养26h,发酵液的酶活力达到332U/mL。结果表明,该菌株从产酶活力和发酵特点等各方面具备工业化开发的潜力。 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
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Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献
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《海洋学报(英文版)》2014,(8):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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Nabil Sultan Pierre Cochonat Jean Fran ois Bourillet Florence Cayocca 《Marine Georesources & Geotechnology》2001,19(2):107-133
This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed. 相似文献