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赖氨酸脱羧酶分子改造及其催化合成戊二胺 被引量:4
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作者 osire tolbert 杨套伟 +5 位作者 乔郅钠 孙杨 徐美娟 张显 邵明龙 饶志明 《食品与发酵工业》 CAS CSCD 北大核心 2022年第1期8-14,共7页
1,5-戊二胺(戊二胺)具有良好的生物活性,广泛应用在农业、医药以及工业等领域。赖氨酸脱羧酶可以催化L-赖氨酸生产戊二胺,为了提高赖氨酸脱羧酶催化合成戊二胺的效率,首先在大肠杆菌中克隆表达了粘质沙雷氏菌来源的赖氨酸脱羧酶(SmcadA... 1,5-戊二胺(戊二胺)具有良好的生物活性,广泛应用在农业、医药以及工业等领域。赖氨酸脱羧酶可以催化L-赖氨酸生产戊二胺,为了提高赖氨酸脱羧酶催化合成戊二胺的效率,首先在大肠杆菌中克隆表达了粘质沙雷氏菌来源的赖氨酸脱羧酶(SmcadA)。生化特征表明,SmcadA最适催化pH为6.0,最适催化温度约为40℃。随后对SmcadA的第348位氨基酸进行了突变研究,筛选获得了催化效率显著提高的突变体Gly348Ala,主要原因是该突变导致蛋白中氨基酸残基和底物之间相互作用的氢键数增加,从而影响其催化效率。最后,对重组菌株细胞进行了戊二胺合成研究,催化反应25 h,含有突变体Gly348Ala的重组菌细胞可以催化合成218.2 g/L戊二胺,野生型SmcadA重组菌仅能催化合成159.2 g/L戊二胺。该研究结果为工业化酶催化合成戊二胺提供了借鉴。 展开更多
关键词 赖氨酸脱羧酶 分子改造 氢键 酶催化 戊二胺
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Clean Monascus pigments production from Chinese rice wine wastes through submerged fermentation
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作者 Mengfei Long Yongchao Cai +6 位作者 Nan Zheng Zhi Lu Wentao Cao Yaxian Li Xiaomei Pei osire tolbert Xiaole Xia 《Food Bioscience》 SCIE 2023年第2期843-850,共8页
The potential for Monascus pigments(MPs)production in a mixture of Chinese rice wine lees,soaked rice wastewater and broken rice was explored.MPs production reached 120.1 U/mL with optimal solid-liquid ratio of cultur... The potential for Monascus pigments(MPs)production in a mixture of Chinese rice wine lees,soaked rice wastewater and broken rice was explored.MPs production reached 120.1 U/mL with optimal solid-liquid ratio of culture medium 1:10 and 20 g/L broken rice addition at shake flask level.We further explored the effects of stirring speed on MPs production in 7.5 L agitated bioreactor.The stirring speed had a great impact on cell morphology and the maximum MPs concentration and yield were 128.4 U/mL and 8174 U/g respectively at 400 rpm.The soluble chemical oxygen demand for the soaked rice wastewater decreased by 78.7%,which was mainly due to the intake of carbohydrates,organic acids and amino acids.Furthermore,a simultaneous fermentation process and production system with two-stage stirring speed control strategy was further developed in the 50 L pilot scale,in which the MPs production reached 158.9 U/mL.Meanwhile,Chinese rice wine wastes were fully utilized without addition of organic solvents during the process and no generation of new waste.Our results showed that Monascus was capable of converting Chinese rice wine wastes into natural pigments by submerged fermentation,which could provide an economic and environmentally friendly approach to reduce the cost of wastes treatment as well as high-value utilization. 展开更多
关键词 Monascus pigments Submerged fermentation Chinese rice wine wastes Pilot scale fermentation Simultaneous fermentation process and production system
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