Metabolic engineering of ammonium release for nitrogen-fixing multispecies microbial cell-factories
Metabolic engineering of ammonium release for nitrogen-fixing multispecies microbial cell-factories
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DOI：
10.1016/j.ymben.2014.03.002
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发表时间：
2014-05-01
影响因子：
8.4
通讯作者：
Curatti, Leonardo
中科院分区：
文献类型：
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作者：
Federico Ortiz-Marquez, Juan Cesar;Do Nascimento, Mauro;Curatti, Leonardo
一些细菌和古生菌进行的生物固氮是最具吸引力的合成氮肥替代品之一。在这项研究中，我们比较了通过活性部位的点突变(D49S突变)来控制棕色固氮菌谷氨酰胺合成酶的最大激活状态，以及通过Delta NIFL突变来破坏氨依赖的动态平衡控制固氮基因表达对细胞释放氨的影响。携带单一D49S突变的菌株在碳/能量限制条件下更高效地产生铵，并在合成微藻-细菌联合体中以牺牲大气N-2为代价持续生长微藻。不同菌株的氨输送对微藻的细胞大小分布有影响，它揭示了固氮和同化之间广泛的交叉调节，扩展了对这一关键代谢途径的现有知识，并可能为进一步改进多功能固氮微生物细胞工厂提供有价值的线索。(C)2014年国际代谢工程学会。爱思唯尔公司出版，版权所有。
The biological nitrogen fixation carried out by some Bacteria and Archaea is one of the most attractive alternatives to synthetic nitrogen fertilizers. In this study we compared the effect of controlling the maximum activation state of the Azotobacter vinelandii glutamine synthase by a point mutation at the active site (D49S mutation) and impairing the ammonium-dependent homeostatic control of nitrogenfixation genes expression by the Delta nifL mutation on ammonium release by the cells. Strains bearing the single D49S mutation were more efficient ammonium producers under carbon/energy limiting conditions and sustained microalgae growth at the expense of atmospheric N-2 in synthetic microalgae-bacteria consortia. Ammonium delivery by the different strains had implications for the microalga's cell-size distribution It was uncovered an extensive cross regulation between nitrogen fixation and assimilation that extends current knowledge on this key metabolic pathway and might represent valuable hints for further improvements of versatile N-2-fixing microbial-cell factories. (C) 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.