Some Aspects of the Endogenous Metabolism of Bacteria

Dawes, E. A.; Ribbons, D. W.

doi:10.1128/mmbr.28.2.126-149.1964

Cited by 122 publications

(44 citation statements)

References 31 publications

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“…Bacterial cells subjected to nutrient starvation often respond by metabolizing intracellular substrates. The concept of endogenous metabolism has been defined as the total of the metabolic reactions that occur when an organism is deprived of compounds that may serve as exogenous substrates (Dawes and Ribbons, 1964). Possible endogenous substrates include the free amino acid pool, protein, RNA, and storage compounds such as polysaccharides (granulose) and lipids (PHB).…”

Section: Upper Left: Butyric Acid (Solid Line) and Acetic Acid (Dashementioning

confidence: 99%

Activity Regeneration in Continuous Clostridium acetobutylicum Bioconversions of Glucose

Reardon

Bailey

1992

Biotechnology Progress

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The regeneration of product‐forming activity by periodic nutrient feeding was studied in a continuous immobilized Clostridium acetobutylicum reactor system. Activity levels were increased by feeding ammonia and vitamins during selected intervals of the experiments; these compounds were not otherwise present in the medium. In contrast with experiments utilizing rich, complex media, regeneration with a defined medium resulted in increased rates of product formation far in excess of rates of concomitant cell growth. During one nutrient feeding phase, the increase in the butyric acid production rate was five times that of the cell growth‐rate increase, while the analogous ratio for butanol was 18. A hypothesis explaining the patterns of substrate consumption and product formation during the regeneration and deactivation periods has been developed: decreasing levels of exogenous ammonia induce the high‐affinity ammonia uptake system, causing the adenylate energy charge of the cells to increase; this in turn leads to the repression of glucose carbon flow through the EMP pathway and to the use of the acid‐forming catabolic reactions for more efficient production of ATP. Pulsewise addition of three different vitamins during one regeneration phase yielded interesting results, including a 50 % increase in butyric acid production rate that appeared to be connected with the addition of biotin. Finally, enumeration of the different morphological types of immobilized cells provided the first measurements of population dynamics in an immobilized cell system. Changes in the numbers of each cell type are consistent with the sporulation and germination processes of C. acetobutylicum observed with suspended cells.

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Section: Upper Left: Butyric Acid (Solid Line) and Acetic Acid (Dashementioning

confidence: 99%

Activity Regeneration in Continuous Clostridium acetobutylicum Bioconversions of Glucose

Reardon

Bailey

1992

Biotechnology Progress

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“…PHB is a unique intracellular reserve of organic carbon and/or chemical energy found in a wide variety of bacteria [1,2], and is regarded as potentially useful biodegradable natural plastics which are not derived from petroleum, together with similar polyesters, polyhydroxyalkanoates (PHA) [3][4][5]. One of the unique properties of PHA is its biodegradability.…”

Section: Introductionmentioning

confidence: 99%

Intracellular degradation of poly(3-hydroxybutyrate) granules of Zoogloea ramigera I-16-M

Saito

Saegusa

Miyata

et al. 1992

FEMS Microbiology Letters

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SUMMARYIntracellular degradation of poly(3-hydroxybutyrate) (PHB) in bacteria is not yet clear. The properties of the autodigestion of native PHB granules from Zoogloea ramigera 1-16-M were examined. The release of D( --)-3-hydroxybutyrate was observed only at pH values higher than about 8.5 and at relatively high ionic strength (optimal concentration 200 mM NaCI). Triton X-100 and diisopropylfluorophosphate inhibited this reaction. Addition of the supernatant fraction of Z. ramigera did not increase the release of o(-)-3hydroxybutyrate from the native PHB granules. On the other hand, using the protease-treated PHB granules from Alcaligenes eutrophus as a substrate, PHB depolymerase activity was detected in the supernatant fraction of Z. ramigera cells. The soluble PHB depolymerase showed similar properties to the enzyme in the PHB granules. Since PHB depolymerase activity was

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“…Although this would not be considered a typical example of the phenomenon of differentiation, the biochemical mechanisms underlying the accumulation of trehalose may well be very similar to those operative in the starving cellular slime mold. There are many examples in the literature of metabolite or end product accumulation to a n unusual extent during periods of starvation (Dawes and Ribbons 1964;Shockman 1965;Pannbacker and Wright 1967). It is interesting to note the similarity between these examples of starvation metabolism and secondary metabolism (Dawes and Ribbons 1964): The accumulated metabolite is not necessarily essential to the survival of the organism (although it may prolong viability during extended periods of starvation).…”

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confidence: 99%

“…There are many examples in the literature of metabolite or end product accumulation to a n unusual extent during periods of starvation (Dawes and Ribbons 1964;Shockman 1965;Pannbacker and Wright 1967). It is interesting to note the similarity between these examples of starvation metabolism and secondary metabolism (Dawes and Ribbons 1964): The accumulated metabolite is not necessarily essential to the survival of the organism (although it may prolong viability during extended periods of starvation). During the course of evolution, however, such metabolites may have been (and may still be) essential to the selection and survival of more complex differentiating systems (Wright 1970;1973).…”

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confidence: 99%