N-acetyl-D-methionine, NaAc and the remains of N-acetyl-L-methionine dramatically affect the purification of L-methionine when purified from the mixture of enzymatically deacylated N-acetyl-DL-methionine, leading to a...N-acetyl-D-methionine, NaAc and the remains of N-acetyl-L-methionine dramatically affect the purification of L-methionine when purified from the mixture of enzymatically deacylated N-acetyl-DL-methionine, leading to a low yield conventionally. Here, this paper reports a successful separation and purification of both L-methionine and N-acetyl-D-methionine by an H ion-exchange column. The pH, L-Met concentration and the ratio between the content of sodium cation and the ion-exchange capacity were optimized to obtain the maximum yield. Experimental results indicate that, under the optimized conditions, the yields of L-methionine and N-acetyl-D-methionine can reach as high as 85% and 75%, respectively.展开更多
糖苷酶是葡萄酒中键合态萜烯类化合物释放的关键酶。为筛选高产糖苷酶的本土植物乳杆菌菌株,以河西走廊产区葡萄酒生产企业自然启动苹果酸-乳酸发酵的酒样为试材,采用p-NP法分别测定筛选菌株的β-D-葡萄糖苷酶、α-L-阿拉伯糖苷酶和α-L...糖苷酶是葡萄酒中键合态萜烯类化合物释放的关键酶。为筛选高产糖苷酶的本土植物乳杆菌菌株,以河西走廊产区葡萄酒生产企业自然启动苹果酸-乳酸发酵的酒样为试材,采用p-NP法分别测定筛选菌株的β-D-葡萄糖苷酶、α-L-阿拉伯糖苷酶和α-L-鼠李糖苷酶活力,并对优选菌株进行酿酒条件适应性分析和葡萄酒微酿试验,探讨供试菌株对葡萄酒挥发性萜烯类香气物质的影响。结果表明,菌株ZX-2、ZX-11、ZX-12、ZX-13、GF-20和GF-26具有较高的糖苷酶活力,经菌落形态特征以及16S r DNA D1/D2区域序列分析鉴定均为植物乳杆菌。酿酒适应性分析结果显示,6株本土植物乳杆菌的发酵耐受性存在差异,其中GF-26菌株的复合因素耐受性最佳。接种菌株GF-26完成苹果酸-乳酸发酵后的霞多丽葡萄酒中,共检测到9种萜烯类物质,与接种酒酒球菌GF-2酒样相比,香气含量增加了27.79%。综合分析,菌株GF-26具有良好的葡萄酒增香酿造应用潜力。展开更多
文摘N-acetyl-D-methionine, NaAc and the remains of N-acetyl-L-methionine dramatically affect the purification of L-methionine when purified from the mixture of enzymatically deacylated N-acetyl-DL-methionine, leading to a low yield conventionally. Here, this paper reports a successful separation and purification of both L-methionine and N-acetyl-D-methionine by an H ion-exchange column. The pH, L-Met concentration and the ratio between the content of sodium cation and the ion-exchange capacity were optimized to obtain the maximum yield. Experimental results indicate that, under the optimized conditions, the yields of L-methionine and N-acetyl-D-methionine can reach as high as 85% and 75%, respectively.
文摘糖苷酶是葡萄酒中键合态萜烯类化合物释放的关键酶。为筛选高产糖苷酶的本土植物乳杆菌菌株,以河西走廊产区葡萄酒生产企业自然启动苹果酸-乳酸发酵的酒样为试材,采用p-NP法分别测定筛选菌株的β-D-葡萄糖苷酶、α-L-阿拉伯糖苷酶和α-L-鼠李糖苷酶活力,并对优选菌株进行酿酒条件适应性分析和葡萄酒微酿试验,探讨供试菌株对葡萄酒挥发性萜烯类香气物质的影响。结果表明,菌株ZX-2、ZX-11、ZX-12、ZX-13、GF-20和GF-26具有较高的糖苷酶活力,经菌落形态特征以及16S r DNA D1/D2区域序列分析鉴定均为植物乳杆菌。酿酒适应性分析结果显示,6株本土植物乳杆菌的发酵耐受性存在差异,其中GF-26菌株的复合因素耐受性最佳。接种菌株GF-26完成苹果酸-乳酸发酵后的霞多丽葡萄酒中,共检测到9种萜烯类物质,与接种酒酒球菌GF-2酒样相比,香气含量增加了27.79%。综合分析,菌株GF-26具有良好的葡萄酒增香酿造应用潜力。
