Effects of Inhibition and Repression on the Utilization of Substrates by Heterogeneous Bacterial Communities

Stumm-Zollinger, Elisabeth

doi:10.1128/aem.14.4.654-664.1966

Cited by 46 publications

(13 citation statements)

References 8 publications

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“…strain ANL was able to utilize simultaneously low concentrations of aniline and glucose. The ability of heterogeneous bacterial communities to metabolize mixtures of carbon compounds simultaneously has long been known (15), and the simultaneous use of several substrates by pure cultures of bacteria has been reviewed by Harder and Dijkhuizen (4). Recently, it was shown that a synthetic compound (methylene chloride) can be degraded simultaneously with acetate by a pure culture of bacteria (7).…”

Section: Discussionmentioning

confidence: 99%

Effects of dissolved organic carbon and second substrates on the biodegradation of organic compounds at low concentrations

Schmidt¹,

Alexander²

1985

Appl Environ Microbiol

131

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Pseudomonas acidovorans and Pseudomonas sp. strain ANL but not Salmonella typhimurium grew in an inorganic salts solution. The growth of P. acidovorans in this solution was not enhanced by the addition of 2.0 jig of phenol per liter, but the phenol was mineralized. Mineralization of 2.0 jig of phenol per liter by P. acidovorans was delayed 16 h by 70 ,ug of acetate per liter, and the delay was lengthened by increasing acetate concentrations, whereas phenol and acetate were utilized simultaneously at concentrations of 2.0 and 13 jig/liter, respectively. Growth of Pseudomonas sp. in the inorganic salts solution was not affected by the addition of 3.0 jig each of glucose and aniline per liter, nor was mineralization of the two compounds detected during the initial period of growth. However, mineralization of both substrates by this organism occurred simultaneously during the latter phases of growth and after growth had ended at the expense of the uncharacterized dissolved organic compounds in the salts solution. In contrast, when Pseudomonas sp. was grown in the salts solution supplemented with 300 jig each of glucose and aniline, the sugar was mineralized first, and aniline was mineralized only after much of the glucose carbon was converted to CO2. S. typhimurium failed to multiply in the salts solution with 1.0 jig of glucose per liter. It grew slightly but mineralized little of the sugar at 5.0 jig/liter, but its population density rose at 10 jig of glucose per liter or higher. The hexose could be mineralized at 0.5 jig/liter, however, if the solution contained 5.0 mg of arabinose per liter. In solutions with this arabinose concentration and glucose levels too low to support growth, the percentage of glucose carbon incorporated into S. typhimurium cells was the same as when the bacterium was grown in solutions with high concentrations of glucose alone. When glucose was the only carbon source for S. typhimurium, the percentage of the glucose carbon assimilated and mineralized progressively declined as the sugar concentration was reduced to levels approaching the threshold for growth. These results indicate that second substrates and uncharacterized dissolved organic carbon may play an important role in controlling the rate and extent of biodegradation of organic compounds at low concentrations. Microorganisms can degrade a variety of synthetic organic compounds present in samples from natural environments at concentrations below 10 puglliter (1, 16). However, it is not certain whether microorganisms can grow at such low concentrations. It has been postulated that substrate uptake will just meet maintenance energy requirements and growth is not possible at sufficiently low substrate concentrations (12). * Corresponding author. to use the uncharacterized DOC were used. In addition, to understand the effect of DOC on the metabolism of synthetic organic substrates, studies were also conducted on the effects of second substrates on the biodegradation of low concentrations of organic compounds. MATERIALS AND METHODS Rad...

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Section: Discussionmentioning

confidence: 99%

Effects of dissolved organic carbon and second substrates on the biodegradation of organic compounds at low concentrations

Schmidt¹,

Alexander²

1985

Appl Environ Microbiol

131

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“…The four polysaccharides studied in this investigation were each broken down at different rates and to different degrees by faecal bacteria. The rapid breakdown of starch suggested that, when a mixture of NSP and starch was available to gut bacteria, fermentation of NSP might be affected by the operation of catabolite control mechanisms [25,26]. The results shown in Fig.…”

Section: Significance Of Polysaccharide Fermentation In the Large Gutmentioning

confidence: 94%

Polysaccharide breakdown by mixed populations of human faecal bacteria

Englyst¹

1987

FEMS Microbiology Letters

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Measurements of polysaccharide‐degrading activity in different fractions of human faeces showed that bacterial polysaccharidases and glycosidases were primarily associated with the washed bacterial fractions. Amylase, pectinase and xylanase were the major polysaccharide‐hydrolysing enzymes detected, whilst α‐L‐arabinofuranosidase, β‐D‐xylosidase, β‐D‐galactosidase and β‐D‐glucosidase were the most active glycosidases. Starch and 3 non‐starch polysaccharides (NSP; pectin, xylan and arabinogalactan) were fermented by mixed populations of human faecal bacteria in batch culture. Detailed carbohydrate analysis demonstrated that starch and pectin were the most rapidly degraded substrates and that arabinogalactan and the relatively insoluble polysaccharide xylan were broken down more slowly. Free sugars and oligosaccharides did not accumulate in culture media with any polysaccharide tested. Time‐course measurements of polysaccharide remaining in the batch culture fermentations showed that the arabinose side chains of pectin, xylan and arabinogalactan were co‐utilised with the backbone sugars. In these cultures, polysaccharide‐degrading activity was mainly cell‐associated, but extracellular polysaccharidase activity increased as the fermentations progressed. Molar ratios of acetate, propionate and butyrate produced in these experiments were dependent upon the polysaccharide substrate tested. Molar ratios of acetate, propionate and butyrate in the starch, arabinogalactan, xylan and pectin fermentations were 50:22:29, 50:42:8, 82:15:3, and 84:14:2, respectively. The presence of starch did not inhibit the breakdown of arabinogalactan, xylan or pectin by faecal bacterial, providing evidence that multicomponent substrate utilisation occurs when complex populations of faecal bacteria are provided with mixed polysaccharide substrates.

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“…Experimental evidence for sequential, concurrent, or interactive substrate utilization patterns have been reported, but the results have usually been explained qualitatively in terms of enzyme induction, the presence of constitutive enzymes, or competitive inhibition. Diauxic growth, with preference for glucose, has been reported by numerous investigators .1- 6 The lag phase between glucose depletion and utilization of the other target substrates varies from 1-4 h7 to 16 h. 8 The lag phase is ascribed to physiological adaptation rather than mu-Biotechnology and Bioengineering, Vol. XXIV, Pp.…”

Section: Introductionmentioning

confidence: 96%

Kinetics of biodegradation of 2,4‐dichlorophenoxyacetate in the presence of glucose

Papanastasiou

Maier

1982

Biotech & Bioengineering

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Biodegradation of 2,4-dichlorophenoxyacetate (2,4-D) and glucose were studied using a 2,4-D acclimated culture. Biodegradation of glucose by the 2,4-D preacclimated culture follows the typical Monod kinetics after a 20-h lag period in the presence or absence of 2,4-D. Biodegradation of 2,4-D by the same culture follows Andrew's "substrate inhibition" model. When both glucose and 2,4-D are available, mutual inhibition is observed. However, the effect on 2,4-D is masked by the fact that larger concentrations of active biomass are produced when glucose is available. This kind of concurrent utilization and interaction results in a substantial reduction of the mean cell residence time in a continuous flow system. It also extends the area of stability of the process into higher dilution rates as well as into higher influent concentrations.

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Effects of Inhibition and Repression on the Utilization of Substrates by Heterogeneous Bacterial Communities

Cited by 46 publications

References 8 publications

Effects of dissolved organic carbon and second substrates on the biodegradation of organic compounds at low concentrations

Effects of dissolved organic carbon and second substrates on the biodegradation of organic compounds at low concentrations

Polysaccharide breakdown by mixed populations of human faecal bacteria

Kinetics of biodegradation of 2,4‐dichlorophenoxyacetate in the presence of glucose

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