ISSN:
1432-072X
Keywords:
Anaerobic degradation
;
Aromatic compounds
;
Rhodopseudomonas palustris
;
ω-Phenylalkane carboxylic acids
;
trans-cinnamic acid
;
3-Phenylpropionic acid
;
4-Phenylbutyric acid
;
β-Oxidation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The mechanism responsible for the initial steps in the anaerobic degradation of trans-cinnamate and ω-phenylalkane carboxylates by the purple non-sulphur photosynthetic bacterium Rhodopseudomonas palustris was investigated. Phenylacetate did not support growth and there was a marked CO2 dependence for growth on acids with greater side-chain lengths. Here, CO2 was presumably acting as a redox sink for the disposal of excess reducing equivalents. Growth on benzoate did not require the addition of exogenous CO2. Aromatic acids with an odd number of side-chain carbon atoms (3-phenylpropionate, 5-phenylvalerate, 7-phenylheptanoate) gave greater apparent molar growth yields than those with an even number of side-chain carbon atoms (4-phenylbutyrate, 6-phenylhexanoate, 8-phenyloctanoate). HPLC analysis revealed that phenylacetate accumulated and persisted in the culture medium during growth on these latter compounds. Cinnamate and benzoate transiently accumulated in the culture medium during growth on 3-phenylpropionate, and benzoate alone accumulated transiently during the course of trans-cinnamate degradation. The transient accumulation of 4-phenyl-2-butenoic acid occurred during growth on 4-phenylbutyrate, and phenylacetate accumulated to a 1:1 molar stoichiometry with the initial 4-phenylbutyrate concentration. It is proposed that the initial steps in the anaerobic degradation of trans-cinnamate and the group of acids from 3-phenylpropionate to 8-phenyloctanoate involves β-oxidation of the side-chain.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00245283
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