Gliessman Jennifer R, Kremer Timothy A, Sangani Amee A, Jones-Burrage Sara E, McKinlay James B
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
FEMS Microbiol Lett. 2017 Jul 6;364(13). doi: 10.1093/femsle/fnx136.
The bacterium Zymomonas mobilis naturally produces ethanol at near theoretical maximum yields, making it of interest for industrial ethanol production. Zymomonas mobilis requires the vitamin pantothenate for growth. Here we characterized the genetic basis for the Z. mobilis pantothenate auxotrophy. We found that this auxotrophy is due to the absence of a single gene, panD, encoding aspartate-decarboxylase. Heterologous expression of Escherichia coli PanD in Z. mobilis or supplementation of the growth medium with the product of PanD activity, β-alanine, eliminated the need for exogenous pantothenate. We also determined that Z. mobilis IlvC, an enzyme better known for branched-chain amino acid synthesis, is required for pantothenate synthesis in Z. mobilis, as it compensates for the absence of PanE, another pantothenate synthesis pathway enzyme. In addition to contributing to an understanding of the nutritional requirements of Z. mobilis, our results have led to the design of a more cost-effective growth medium.
运动发酵单胞菌能以接近理论最大产量天然产生乙醇，这使其在工业乙醇生产方面具有吸引力。运动发酵单胞菌生长需要泛酸维生素。在此，我们对运动发酵单胞菌泛酸营养缺陷型的遗传基础进行了表征。我们发现这种营养缺陷型是由于缺失一个单一基因panD所致，该基因编码天冬氨酸脱羧酶。在运动发酵单胞菌中异源表达大肠杆菌PanD，或在生长培养基中添加PanD活性产物β-丙氨酸，消除了对外源泛酸的需求。我们还确定，运动发酵单胞菌IlvC（一种以参与支链氨基酸合成而更为人所知的酶）是运动发酵单胞菌合成泛酸所必需的，因为它补偿了另一种泛酸合成途径酶PanE的缺失。除了有助于理解运动发酵单胞菌的营养需求外，我们的研究结果还促成了一种更具成本效益的生长培养基的设计。
