Utilization of D-Lactate as an Energy Source Supports the Growth of Gluconobacter oxydans
Utilization of D-Lactate as an Energy Source Supports the Growth of Gluconobacter oxydans
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利用 D-乳酸作为能源支持氧化葡萄糖杆菌的生长
DOI：
10.1128/aem.00527-15
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发表时间：
2015-06-01
影响因子：
4.4
通讯作者：
Xu, Ping
中科院分区：
文献类型：
--
作者：
Sheng, Binbin;Xu, Jing;Xu, Ping
在本研究中，D-乳酸被确定为支持氧化葡糖醛酸621 H生长的少数可用有机酸之一。有趣的是，该菌株使用D-乳酸作为能源，而不是作为碳源，不像其他利用乳酸的细菌。G.因此，研究了oxydans 621 H对D-乳酸的影响。虽然两种推定的NAD非依赖性D-乳酸脱氢酶GOX 1253和GOX 2071能够氧化D-乳酸，但GOX 1253是唯一能够支持D-乳酸驱动的菌株生长的酶。GOX 1253被表征为对D-乳酸具有高活性的膜结合脱氢酶，而GOX 2071被表征为对D-2-羟基酸具有广泛底物特异性的可溶性氧化酶。后者使用分子氧作为直接电子受体，这是以前在D-乳酸氧化酶中没有报道的特征。本研究不仅阐明了G. oxydans对D-乳酸的影响，同时也为重要工业微生物和新型D-乳酸氧化酶的应用提供了新的思路。
D-Lactate was identified as one of the few available organic acids that supported the growth of Gluconobacter oxydans 621H in this study. Interestingly, the strain used D-lactate as an energy source but not as a carbon source, unlike other lactate-utilizing bacteria. The enzymatic basis for the growth of G. oxydans 621H on D-lactate was therefore investigated. Although two putative NAD-independent D-lactate dehydrogenases, GOX1253 and GOX2071, were capable of oxidizing D-lactate, GOX1253 was the only enzyme able to support the D-lactate-driven growth of the strain. GOX1253 was characterized as a membrane-bound dehydrogenase with high activity toward D-lactate, while GOX2071 was characterized as a soluble oxidase with broad substrate specificity toward D-2-hydroxy acids. The latter used molecular oxygen as a direct electron acceptor, a feature that has not been reported previously in D-lactate-oxidizing enzymes. This study not only clarifies the mechanism for the growth of G. oxydans on D-lactate, but also provides new insights for applications of the important industrial microbe and the novel D-lactate oxidase.