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Twelve samples derived from different locations in south central area of China are treated by enrichment and spread-plate
technique for initial screening. Seven chitinase-producing strains are isolated. The chitinase present in the culture supernatant
of strain CS-01 possesses the maximum activity of 0.118 U/mL. Analysis of the morphological feature and the ITS rDNA sequence
reveals that strain CS-01 belongs to Aspergillus fumigatus. Production of the chitinase is regulated by a inducible way and the maximum activity appears at 36 h in colloidal chitin
culture. Purification of the chitinase is carried out by salting out, gel filtrate chromatography and anion exchange chromatography
sequentially. Native-PAGE and SDS-PAGE indicate that the chitinase from A. fumigatus CS-01 is a monomer with the relative molecular mass estimated to be 4.50×104. Its maximum activity appears at pH 5 and 55 °C. The chitinase is stable at pH 4.0–7.5 and below 45 °C.
Foundation item: Projects(50621063, 50674101) supported by the National Natural Science Foundation of China 相似文献
2.
Identification and fermentation optimization of protopectinase-overproducing strain Aspergillus niger CD-01 for pectin production 总被引:1,自引:1,他引:0
In order to solve the citrus peel resource waste problem and minimize the drawbacks of chemical extraction of pectin, a protopectinase-overproducing
strain CD-01 for pectin production was isolated from a pit soil dumped with perished orange in Changde City, Hunan Province
of China. The strain CD-01 had the same morphology and 28S rRNA gene sequence (FJ184995) as that of Aspergillus niger (ATCC 64028). It was thus identified and named as Aspergillus niger CD-01. The fermentation condition was optimized based on L9(34) orthogonal experimental design and the variances analyses. The results show that the optimal condition for producing pectin
is as follows: time 36 h, temperature 35 °C, pH 5, and urea as the nitrogen source. Under this condition, the pectin yield
can reach up to 24.5%. This shows a great potential of Aspergillus niger CD-01 in pectin extraction from citrus.
Foundation item: Projects(50621063, 50674101) supported by the National Natural Science Foundation of China 相似文献
3.
Growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 grown on different substrates 总被引:1,自引:0,他引:1
The growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 isolated from an acid hot spring in Tengchong,Yunnan Province,China were investigated cultured on different substrates including soluble substrate ferrous sulfate and nonsoluble solid substrates S~0,pyrite and chalcopyrite.The growth characteristics of the cells in each substrate were characterized with the changes in cell number,pH,E_h,and concentrations of Fe~(2+)or SO_4~(2-),or ratios of[Fe~(2+)]to[Fe~... 相似文献
4.
A new strain Acidithiobacillus albertensis BY-05 for bioleaching of metal sulfides ores 总被引:4,自引:2,他引:4
An acidophilic,rod-shaped Gram-negative sulfur oxidizing strain BY-05 was isolated from an acid mine drainage of copper ore in Baiyin area,Gansu Province,China.Ultrastructural studies show that the isolate has a tuft of polar flagella and possesses sulfur granules with clear membrane adhering to the cell innermembrane.Physiological study shows that this isolate grows autotrophically and aerobically by oxidizing S0and reduced inorganic sulfur compounds(SO, 2 23-SO, 2 24- S2 -and ZnS)with the optimum growth at pH 3.5-4.0 and at the temperature range of 25-30℃.The 16S rRNA gene sequence(DQ 423683)of strain BY-05 has 100%sequence similarity to that of Acidithiobacillus albertensis(DSM 14366).So it is identified and named as A. albertensis BY-05.Bioleaching experiments with this new strain show that it can play an important role in recovery of metals from chalcopyrite and sphalerite. 相似文献
5.
The biosorption mechanism of Cr (Ⅵ) ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr (Ⅵ) consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-IR spectra of K_2Cr_2O_7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp. show that the speciation of chromium that binds to the cells of Synechococcus sp. is Cr (Ⅲ), instead of Cr (Ⅵ), and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr (Ⅲ). Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr (Ⅵ), and the results of FT-IR show that the biosorption of Cr (Ⅵ) follows two subsequent steps, biosorption of Cr_2O_(7~)2-))by electrostatical force at the protonated active sites and reduction of Cr_2O_(7~(2-)) to Cr3+ by the reductive groups on the surface of the biosorbents. 相似文献
6.
福建某铅锌浮选尾矿中铅、锌、银的品位分别为0.23%、2.11%、36.3 g/t,其中锌和银有较高回收价值。该尾矿中主要金属矿物为闪锌矿、黄铁矿和方铅矿,非金属矿物以方解石和石英为主。针对矿石特点,采用优先浮选开展工艺优化试验。结果表明:在磨矿细度为-0.074 mm占69.92%的条件下,以石灰为pH调整剂,硫酸锌为抑制剂,乙硫氮为捕收剂,2#油为起泡剂,经1粗3精1扫浮铅,可获得铅品位4.56%、银品位320 g/t,铅回收率15.55%、银回收率6.63%的银铅精矿;针对选铅尾矿,以石灰为pH调整剂,硫酸铜为活化剂,丁基黄药为捕收剂,2#油为起泡剂,经1粗3精2扫浮锌,可获得锌品位37.32%、银品位152 g/t,锌回收率73.25%、银回收率18.80%的锌精矿。试验指标较好,可为该尾矿的综合利用提供数据支撑。 相似文献
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对4株纯的极端嗜热古菌及它们的混合菌在生物浸出黄铜矿过程中的硫氧化活性进行对比研究。结果表明,混合菌比纯菌拥有更高的硫氧化活性,它大幅度促进黄铜矿浸出率的提高。表征嗜热古菌硫氧化活性的参数值通常受很多因素的影响,以致在不同的硫氧化菌和不同的条件下生物浸出黄铜矿时,这些参数很难准确地反映出相应的硫氧化活性。因此,期待找到一种能有效表征浸矿菌硫氧化活性的方法。 相似文献
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为了得到煤矸石山酸性废水处理的专属功能微生物,从湖南湘潭某煤矸石山周边土壤中分离筛选硫酸盐还原菌,分析菌株的16S rRNA基因序列,形态和生理生化特性,并利用得到的菌株处理矸石山酸性废水。16S rRNA基因序列分析表明,所分离得到的硫酸盐还原菌株S-7与Desulfuromonas alkenivorans同源性达到99.0%。该菌株为杆状稍有弯曲,能运动,大小(0.5~0.8)μm×(3.0~4.0)μm,革兰氏染色显阴性,最适生长温度为30℃,最适p H值范围6~8,酵母粉为最好的碳源和氮源,硫酸钠为最适合硫源,菌株经培养96 h后细胞浓度高达1.76×109个/m L。培养初始p H为7时,6 d可去除体系中90%硫酸根离子,而不同硫酸根离子浓度对菌株生长和硫酸盐去除效率影响不明显。S-7菌株对矸石山酸性废水中Fe,Mn,Pb和Zn四种重金属离子均存在处理效果,整体上去除效率为PbFeZnMn,其中Pb离子经7 d处理后去除率达到100%。 相似文献