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脂肪酶催化合成生物柴油的研究 总被引:78,自引:0,他引:78
生物柴油是用动植物油脂或长链脂肪酸与甲醇等低碳醇合成的脂肪酸甲酯,是一种替代能源。这里探讨了生物法制备生物柴油的过程,采用脂肪酶酯化和酯交换两条工艺路线进行催化合成。深入研究制备过程中,不同脂肪酶、酶的用量和纯度、有机溶剂、低碳醇的抑制作用、吸水剂的作用、反应时间和进程、底物的特异性和底物摩尔比等参数对酯化过程的影响。试验结果表明,采用最佳酯化反应参数和分批加入甲醇并用硅胶作脱水剂的工艺过程,酯化率可以达到92%,经分离纯化后的产品GC分析的纯度可达98%以上,固定化酶的使用半衰期可达到360h。同时对酯交换制备生物柴油过程中,甲醇的用量和甲醇的加入方式对脂肪酶催化过程的影响作了初步研究,优化后的酯交换率可达到83%。 相似文献
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Sawao Murao Hiroto Nagano Sei Ogura Toyokazu Nishino 《Bioscience, biotechnology, and biochemistry》2013,77(7):2113-2118
Synthesis of trehalose from maltose by a coupled enzyme system with trehalose Phosphorylase and maltose Phosphorylase has been studied. Trehalose Phosphorylase was partially purified from Euglena gracilis and maltose Phosphorylase was obtained from Lactobacillus brevis. The optimum pH of the reaction was 6.5~7.0 and the reaction rate was faster in the rection mixture containing a low concentration of phosphate. The final ratio of conversion (the ratio of trehalose to maltose) in the pH range between 6.0 and 8.0 was about 60%.Immobilized maltose and trehalose Phosphorylase in κ-carageenan could be used without any appreciable loss of activity for batch reactions at least 10 times. 相似文献
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Using Novozym 435 as catalyst, the syntheses of ethyl ferulate (EF) from ferulic acid (4-hydroxy 3-methoxy cinnamic acid)
and ethanol, and octyl methoxycinnamate (OMC) from p-methoxycinnamic acid and 2-ethyl hexanol were successfully carried out in this study. A conversion of 87% was obtained within
2 days at 75 °C for the synthesis of EF. For the synthesis of OMC at 80 °C, 90% conversion can be obtained within 1 day. The
use of solvent and high reaction temperature resulted in better conversion for the synthesis of cinnamic acid derivatives.
Some cinnamic acid esters could also be obtained with higher conversion and shorter reaction times in comparison to other
methods reported in the literature. The enzyme can be reused several times before significant activity loss was observed.
Revisions requested 10 January 2006; Revisions received 17 January 2006 相似文献
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The overproduction of tumor necrosis factor-α (TNF-α) was suppressed by orally administering a perilla leaf extract (PLE). When mice were successively injected with OK-432, severe TNF-α was induced in the serum, but this elevated TNF-α level was reduced after an oral administration of PLE (400 μl/mouse). Oral administration of PLE also inhibited TNF-α production that was induced by muramyl dipeptide (500 μg/mouse) and OK-432 (3 KE/mouse). These characteristics were obtained from all strains of perilla. The inhibitory activity against TNF-α production was heat-stable, and the existence of several active molecules was suggested. When PLE was passed through an ultrafilter, the inhibitory activity against TNF-α production was collected in those fractions with a mass of 0.5 to 1 kDa and more than 10 kDa. When PLE was solvent-extracted, the strongest activity was recognized with aqueous preparation, although significant activity was also detected in preparations extracted with n-hexane and ethyl acetate. These findings suggest that the daily use of certain functional foods may be useful for controlling the host defense system. 相似文献
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本文建立了丙氨酸在醋酸缓冲液中形成丙氨酸-铜配离子及其十二烷基磺酸配离子对,使其紫外无吸收的丙氨酸在230nm处于有强紫外吸收,从而对酶法合成中的丙氨酸进行定量分析.该法在0~50mg/L范围内有良好的线性关系,直线方程为A(230)=0.01712·C(n=5)C:mg/L)。相关系数为0.9994,回收率为96.8%~104.0%,且该法不受酶反应液的影响,实验结果证明该检测体系简单、实用、测定结果可靠。 相似文献
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酶法合成中色氨酸的分离 总被引:2,自引:0,他引:2
本文对酶法合成中色氨酸的分离进行了研究,筛选出两种合适的树脂:~#330和~#732。实验数据表明:两种树脂串联能有效地将残留的底物吲哚去除,并且对色氨酸总的分离回收率大于70%。这就为今后酶法合成色氨酸工艺产业化提供了必要的数据。 相似文献
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酶法合成抗病毒药物阿糖腺苷 总被引:2,自引:0,他引:2
目的:为了开发一种生产阿糖腺苷的有效方法。方法:研究了以产气肠杆菌完整细胞为催化剂酶法合成阿糖腺苷,优化了菌体培养条件以及酶反应条件。结果:在培养基中添加0.5%葡萄糖,33℃下培养16h,既能得到较多菌体,又能使菌体的催化活性保持较高。酶反应在pH7.0、25mmol/L的磷酸钾缓冲液中进行,底物浓度为阿糖尿苷30mmol/L,腺嘌呤10mmol/L,加入10%湿菌体,在60℃下振荡反应48h,腺嘌呤转化率可达90%。结论:酶法合成阿糖腺苷可应用于大规模工业化生产。 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(2):312-319
The soluble and insoluble fractions obtained after sonication and centrifugation of Bifidobacterium adolescentis M101–4 cells were examined, and both of these fractions exhibited mitogenic activity in art assay of murine splenocytes and Peyer’s patch cells in vitro. The soluble fraction was further treated by a 6-step procedure involving proteinase K-treatment, ultrafiltration with a 50-kDa cut-off molecular-sieving membrane, anion-exchange chromatography, dialysis, ultrafiltration through a 6-kDa cut-off membrane filter, and gel-filtration to yield a soluble high molecular weight fraction (SHF) which was effective for stimulating the proliferation of murine splenocytes. Almost three quarters of this fraction by weight was found to consist of carbohydrates containing glucose and galactose as major constituents, and the average molecular weight was estimated to be between 60,000 and 2,460,000, with the main peak at 1,550,000 Da, by the retention time of gel permeation chromatography. A structural analysis by 1H- and 13C-nuclear magnetic resonance and methylation indicated that SHF contained polysaccharides consisting of -4Galp1-, -4Glcp1-, and -6Glcp1- as the major residues, and Galf1- and -6Galf1- as the minor residues. Immunopotentiating SHF was found to contain galactofuranosyl residues as characteristic constituents which had not been previously detected in other soluble fractions from Gram-positive bacteria. 相似文献