Acinetobacter radioresistens S13 is able to grow on either phenol or benzoate as sole carbon and energy sources, catabolising them through the -ketoadipate pathway. It was previously established that a double set of genes for benzoate and phenol degradation exist and two isozymes of C1,2O, having similar catalytic properties, have been characterised. Kinetic analysis of the growth of A. radioresistens S13 showed that this bacterium can degrade phenol rapidly and efficiently (qp max = 9.56 mmol/g/h, YX/p = 16.31 g/Cmol), while benzoate supports less efficient growth (qb max = 6.80 mmol/g/h, YX/p = 9.792 g/Cmol). In order to determine whether these differences result from different catalytic properties or from different expression patterns of the catabolic enzymes involved, functional proteomics and transcriptomics analyses have been carried out. Cells were grown on a non-aromatic carbon source (acetate) and used to inoculate benzoate or phenol growth media. Samples, collected at different phases of the cultures, were analysed by both proteomic and transcriptomic techniques and confirmed that while benzoate induces the enzymes for both benzoate and phenol degradation, phenol does not induce the expression of benzoate catabolic genes. These observations are confirmed by the fact that growth on benzoate acclimatizes cells for phenol degradation, while the inverse is not true. Furthermore, benzoate induces the biosynthesis of higher amounts of the enzymes involved in the common part of the two pathways. These results suggest that the bottleneck in benzoate biodegradation could be the conversion to catechol, the first common metabolic intermediate.
Regulation of benzoate and phenol catabolic pathway in Acinetobacter radioresistens S13: comparison between proteomic and transcriptomic data
MAZZOLI, Roberto;PESSIONE, Enrica;PRUNOTTO, LAURA;BARELLO, CRISTINA;GIUNTA, Carlo;
2003-01-01
Abstract
Acinetobacter radioresistens S13 is able to grow on either phenol or benzoate as sole carbon and energy sources, catabolising them through the -ketoadipate pathway. It was previously established that a double set of genes for benzoate and phenol degradation exist and two isozymes of C1,2O, having similar catalytic properties, have been characterised. Kinetic analysis of the growth of A. radioresistens S13 showed that this bacterium can degrade phenol rapidly and efficiently (qp max = 9.56 mmol/g/h, YX/p = 16.31 g/Cmol), while benzoate supports less efficient growth (qb max = 6.80 mmol/g/h, YX/p = 9.792 g/Cmol). In order to determine whether these differences result from different catalytic properties or from different expression patterns of the catabolic enzymes involved, functional proteomics and transcriptomics analyses have been carried out. Cells were grown on a non-aromatic carbon source (acetate) and used to inoculate benzoate or phenol growth media. Samples, collected at different phases of the cultures, were analysed by both proteomic and transcriptomic techniques and confirmed that while benzoate induces the enzymes for both benzoate and phenol degradation, phenol does not induce the expression of benzoate catabolic genes. These observations are confirmed by the fact that growth on benzoate acclimatizes cells for phenol degradation, while the inverse is not true. Furthermore, benzoate induces the biosynthesis of higher amounts of the enzymes involved in the common part of the two pathways. These results suggest that the bottleneck in benzoate biodegradation could be the conversion to catechol, the first common metabolic intermediate.
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