Anaerobic Degradation of the Benzene Nucleus by a Facultatively Anaerobic Microorganism
Anaerobic Degradation of the Benzene Nucleus by a Facultatively Anaerobic Microorganism
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兼性厌氧微生物对苯核的厌氧降解
DOI：
10.1128/jb.102.2.430-437.1970
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发表时间：
1970
影响因子：
3.2
通讯作者：
I. Chinoy
中科院分区：
文献类型：
--
作者：
B. Taylor;W. Campbell;I. Chinoy
以对羟基苯甲酸为底物，硝酸盐为电子受体，通过选择性培养，分离到一株细菌。它通过硝酸盐呼吸作用在一系列芳香化合物上有氧或厌氧生长。该微生物被鉴定为假单胞菌，并被赋予俗名假单胞菌PN-1。苯甲酸酯和对羟基苯甲酸酯经原儿茶酸需氧代谢，然后在原儿茶酸-4，5-加氧酶催化下发生Meta裂解，生成α-羟基-γ-羧基粘康酸半醛。假单胞菌PN-1生长迅速对羟基苯甲酸酯在严格的厌氧条件下，提供硝酸盐存在，即使原儿茶酸-4，5-加氧酶被抑制。在对羟基苯甲酸盐上厌氧生长的细胞悬浮液用硝酸盐氧化苯甲酸盐，每添加μ摩尔苯甲酸盐产生4至5 μ摩尔CO2;这些细胞不会在有氧条件下氧化苯甲酸盐。在不同芳香族化合物上有氧或无氧生长的细胞用氧气或硝酸盐氧化芳香族底物的模式表明，苯甲酸盐而不是原儿茶酸盐是无氧代谢早期阶段的关键中间体。得出的结论是，芳环的厌氧分解的途径是不同的，完全不同于有氧途径。讨论了假单胞菌PN-1厌氧降解苯核的机理。
A bacterium was isolated by elective culture with p-hydroxybenzoate as substrate and nitrate as electron acceptor. It grew either aerobically or anaerobically, by nitrate respiration, on a range of aromatic compounds. The organism was identified as a pseudomonad and was given the trivial name Pseudomonas PN-1. Benzoate and p-hydroxybenzoate were metabolized aerobically via protocatechuate, followed by meta cleavage catalyzed by protocatechuic acid-4,5-oxygenase, to yield α-hydroxy-γ-carboxymuconic semialdehyde. Pseudomonas PN-1 grew rapidly on p-hydroxybenzoate under strictly anaerobic conditions, provided nitrate was present, even though protocatechuic acid-4,5-oxygenase was repressed. Suspensions of cells grown anaerobically on p-hydroxybenzoate oxidized benzoate with nitrate and produced 4 to 5 μmoles of CO2 per μmole of benzoate added; these cells did not oxidize benzoate aerobically. The patterns of the oxidation of aromatic substrates with oxygen or nitrate by cells grown aerobically or anaerobically on different aromatic compounds indicated that benzoate rather than protocatechuate was a key intermediate in the early stages of anaerobic metabolism. It was concluded that the pathway for the anaerobic breakdown of the aromatic ring is different and quite distinct from the aerobic pathway. Mechanisms for the anaerobic degradation of the benzene nucleus by Pseudomonas PN-1 are discussed.