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As a new mutagenetic method, low-energy ion implantation has been used widely in many research areas in recent years. In order to obtain some industrial strains with high xylanase yield, the wild type strain Aspergillus niger A3 was mutated by means of nitrogen ions implantation (10 keV, 2.6× 10^14 ~ 1.56 × 10^15 ions/cm^2) and a mutant N212 was isolated subsequently. However, it was found that the initial screening means of the high-yielding xylanase strains such as transparent halos was unfit for first screening. Compared with that of the wild type strain, xylanase production of the mutant N212 was increased from 320 IU/ml to 610 IU/ml, and the optimum fermentation temperature was increased from 28 ℃ to 30 ℃. 相似文献
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In order to obtain an industrial strain with a higher L(+)-lactic acid yield, the strain Rhizopus oryzae RF3608 was mutated by means of nitrogen ion beam implantation and the mutant strain RLC41-6 was isolated. Under optimal conditions the yield of L(+)-lactic acid produced in a shake-flask reached 133 g/L - 137 g/L after 36 h cultivation, indicating that the conversion rate based on glucose was as high as 88% - 91% and the productivity was 3.75 g/L.h. It was almost a 115% increase in lactic acid production compared with the original strain RF3608. 相似文献
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研究了以壳聚糖为载体交联-吸附单宁酸酶后的化学特性。结果表明:固定化单宁酸酶(简称“ITA”)的最适反应pH为3.0,原酶(简称“TA”)为5.5;ITA最适反应温度为50℃,TA为40℃;ITA的Km(app)为1.3845×10(-1)mol/L,TA为6.7500×10(-5)mol/L;ITA在pH3.0~8.0的范围内残存酶活大于60%,ITA在pH3.0~6.0范围内残存酶活大于60%;ITA在80℃的水浴中保温1h,酶活力仍未见下降,而TA在60℃水浴中保温30min酶已失活;ITA和TA在4℃和30℃的条件下,贮藏20d后,ITA的残存活性大于40%,TA的残存活性小于20%。 相似文献
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花生四烯酸的研究概况及应用前景 总被引:6,自引:0,他引:6
多不饱和脂肪酸(Polyunsaturated fatty acids,PUFAs)是指含两个以上双键的一类长链脂肪酸。在微生物体内,PUFAs的合成通常是以单不饱和脂肪酸、油酸为底物,合成途径中,有两个主要的反应,即碳链的增长和去饱和作用。链增长是供体(乙酰辅酶A或丙二酰辅酶A)上的两个碳原子被引入增加碳链长度。而亚油酸的链增长和去饱和则有两个不同的代谢方向,见图1[1]。 PUFAs对人体健康的重要作用已为人们所广泛认识,有人也称它们为维生素F。天然存在的PUFAs种类繁多,其中有3种显得特别… 相似文献
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Arachidonic acid(AA) is one of the most important PUFAs(polyunsaturated fatty acids) in human body.A high-yield arachidonic acid-producing strain(mortierella aplina) was selected by ion implantation(the relative content of arachidonic acid is 70.2% among all fatty acids).This paper mainly introduced the structure,distribution,source,physiologic healthcare function and application of AA. 相似文献
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利用亚硝基胍对隐甲藻ATCC30556进行诱变处理,通过30℃高温培养初筛及摇瓶发酵复筛,得到二十二碳六烯酸(DHA)产量稳定提高的突变株LS1057,其DHA占总脂肪酸的含量从出发株的25.78%提高到32.02%。研究摇瓶发酵条件对突变株发酵的影响,结果表明:在初始pH6.5、温度26℃、转速150r/min的发酵条件下培养216h后,其生物量、总油脂产量及DHA产量分别达到14.06、3.14g/L和1.057g/L,分别比出发藻株提高了21.31%、69.73%和121.59%。 相似文献
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Bacillus subtitles JA isolated by our laboratory produced a large amount of antifungal substances, which had strong inhibitory activity against various plant pathogenic fungi,such as Rhizoctonia solani, l?usarium graminearum and so on. Ion beam implantation as a new mutagenic methods was applied in our studay. After B. subtitles JA was implanted by N^ ions,a strain designated as B. subtitles JA-026 was screened and obtained, which had a higher ability to produce those antifungal substances. A series of experiments indicated that the antifungal substances were thermostable and partially sensitive to proteinases K and tryproteinase. When the fermentating broth was fractionated with ammonium sulphate of a final saturation of 70%,the precipitate-enhanced inhibitory activity while the supernatant lost this activity. It appeared that the antifungal substances were likely to be protein. 相似文献