期刊
BIOPROCESS AND BIOSYSTEMS ENGINEERING
卷 35, 期 8, 页码 1437-1444出版社
SPRINGER
DOI: 10.1007/s00449-012-0732-2
关键词
Enzymatic L-aspartate synthesis; L-Aspartate ammonia-lyase immobilization; Eupergit (R) C; MANA-agarose; LentiKats (R)
资金
- Spanish MICINN [CTQ2011-28398-CO2-01, EUI2008-03615]
- Generalitat de Catalunya [2009SGR281]
- AECID (Spanish MAEC)
l-Aspartate ammonia-lyase from Bacillus sp. YM55-1 (AspB, EC 4.3.1.1) catalyzes the reversible conversion of l-aspartate (Asp) into fumarate and ammonia with a high specific activity toward the substrate. AspB was expressed in Escherichia coli and partially purified by heat precipitation and saturation with ammonium sulfate reaching purification factor of 7.7 and specific activity of 334 U/mg of protein. AspB was immobilized by covalent attachment on Eupergit(A (R)) C (epoxy support) and MANA-agarose (amino support), and entrapment in LentiKats(A (R)) (polyvinyl alcohol) with retained activities of 24, 85 and 63 %, respectively. Diffusional limitations were only observed for the enzyme immobilized in LentiKats(A (R)) and were overcome by increasing substrate concentration. Free and immobilized AspB were used for the synthesis of aspartate achieving high product concentration (a parts per thousand yen450 mM) after 24 h of reaction. Immobilized biocatalysts were efficiently reused in 5 cycles of Asp synthesis, keeping over 90 % of activity and reaching over 90 % of conversion in all the cases.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据