Molecular size distributions of a macromolecular polysaccharide (dextran) during its biodegradation in batch and continuous cultures

Gregory M. Haldane, Bruce Ernest Logan

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Although the molecular size distribution of dissolved organic matter (DOM) can affect the performance of biological wastewater treatment systems, limited information is available on the macromolecule breakdown in these reactors. In this study, we examined the degradation of a single, well-defined polysaccharide (dextran; 70,000 average molecular weight) in axenic culture using a dextran-degrading bacterium isolated from wastewater (CDC group IIi). In suspended batch and continuous cultures fed dextran as a sole carbon source, there was an accumulation of both intermediate (< 10,000 amu) and small (< 1000 amu) molecular weight carbohydrates in solution. In batch culture, the maximum increase in concentration of intermediate-sized carbohydrates was 14% (17 mg l-1) of the initial dextran concentration. In continuous culture, 54% of the effluent polysaccharides were < 10,000 amu although the influent contained less than 6% of this size fraction. This represents an overall net production in the small and intermediate sized carbohydrate concentrations in the chemostat of 143 mg l-1 (26%) and 116 mg l-1 (21%), under conditions where only 6% (34 mg l-1) of carbohydrates entering the chemostat were completely removed. These results indicate that polysaccharides can be released back into solution before being completely utilized by suspended microbes, producing large transformations in size distributions with only minimal changes in total carbohydrate concentrations.

Original languageEnglish (US)
Pages (from-to)1873-1878
Number of pages6
JournalWater Research
Volume28
Issue number9
DOIs
StatePublished - Jan 1 1994

Fingerprint

Dextran
Polysaccharides
Carbohydrates
Biodegradation
polysaccharide
carbohydrate
biodegradation
Chemostats
chemostat
Molecular weight
Macromolecules
dissolved organic matter
Wastewater treatment
Biological materials
Effluents
Bacteria
Wastewater
information system
effluent
wastewater

All Science Journal Classification (ASJC) codes

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

Cite this

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abstract = "Although the molecular size distribution of dissolved organic matter (DOM) can affect the performance of biological wastewater treatment systems, limited information is available on the macromolecule breakdown in these reactors. In this study, we examined the degradation of a single, well-defined polysaccharide (dextran; 70,000 average molecular weight) in axenic culture using a dextran-degrading bacterium isolated from wastewater (CDC group IIi). In suspended batch and continuous cultures fed dextran as a sole carbon source, there was an accumulation of both intermediate (< 10,000 amu) and small (< 1000 amu) molecular weight carbohydrates in solution. In batch culture, the maximum increase in concentration of intermediate-sized carbohydrates was 14{\%} (17 mg l-1) of the initial dextran concentration. In continuous culture, 54{\%} of the effluent polysaccharides were < 10,000 amu although the influent contained less than 6{\%} of this size fraction. This represents an overall net production in the small and intermediate sized carbohydrate concentrations in the chemostat of 143 mg l-1 (26{\%}) and 116 mg l-1 (21{\%}), under conditions where only 6{\%} (34 mg l-1) of carbohydrates entering the chemostat were completely removed. These results indicate that polysaccharides can be released back into solution before being completely utilized by suspended microbes, producing large transformations in size distributions with only minimal changes in total carbohydrate concentrations.",
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Molecular size distributions of a macromolecular polysaccharide (dextran) during its biodegradation in batch and continuous cultures. / Haldane, Gregory M.; Logan, Bruce Ernest.

In: Water Research, Vol. 28, No. 9, 01.01.1994, p. 1873-1878.

Research output: Contribution to journalArticle

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