Mixotrophic Capabilities of Alcaligenes eutrophus
Mixotrophic Capabilities of Alcaligenes eutrophus
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真养产碱菌的混合营养能力
DOI：
10.1099/00221287-130-8-1987
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
C. Friedrich
中科院分区：
文献类型：
--
作者：
U. Kärst;C. Friedrich
兼性化能自养产碱杆菌能够同时利用有机和无机底物，即兼养生长。在琥珀酸限制生长条件下，研究了该菌的兼养能力。在没有二氧化碳的气体环境中含有氢分子的真养生物。在0.2h-1的稀释率（D）下，混合营养细胞产率比单独使用琥珀酸盐的异养产率增加135%。总碳分析表明，在这些条件下，95%的琥珀酸酯碳转化为细胞碳。混合营养产量仅略有下降，在稀释率低于0.2 h-1，但显着在较高的稀释率，只有18%以上的异养产量在D = 0.32 h-1。与其它兼性化能自养生物不同，A.从H2氧化（Hox-）或自养代谢（Cfx-）缺陷的突变体以及从放射性底物的掺入研究中可以明显看出，真养型需要H2氧化（Hox）和自养CO2固定（Cfx）。Cfx突变体HF 17的细胞产量在加入H2后仅略有增加（增加14%），表明A.真养型改变异养基质的代谢是有限的。在相同的生长条件下，Hox突变体并没有增加它们的细胞产量。
The facultatively chemolithoautotrophic hydrogen bacterium Alcaligenes eutrophus was able to utilize organic and inorganic substrates concomitantly, i.e. to grow mixotrophically. The mixotrophic capabilities were investigated under succinate-limited growth of A. eutrophus with molecular hydrogen in a gas atmosphere devoid of carbon dioxide. At a dilution rate (D) of 0.2 h-1, the mixotrophic cellular yield was increased by 135% over the heterotrophic yield with succinate alone. Total carbon analysis revealed that under these conditions 95% of the succinate carbon was converted to cell carbon. The mixotrophic yield decreased only slightly at dilution rates lower than 0.2 h-1 but significantly at higher dilution rates and was only 18% above the heterotrophic yield at D = 0.32 h-1. Unlike other facultative chemoautotrophs, mixotrophic growth of A. eutrophus required both H2 oxidation (Hox) and autotrophic CO2 fixation (Cfx), as evident from mutants defective in either H2 oxidation (Hox-) or autotrophic metabolism (Cfx-), as well as from incorporation studies of radioactive substrates. The cellular yield of a Cfx- mutant, HF17, increased only slightly (by 14%) upon the addition of H2, indicating that the ability of A. eutrophus to change the metabolism of a heterotrophic substrate was limited. Hox- mutants did not increase their cellular yield under identical growth conditions.