ISOLATION, IDENTIFICATION, AND METABOLIC ROLE OF THE SUDANOPHILIC GRANULES OF ZOOGLOEA RAMIGERA

Area of Science:

• Microbiology
• Biochemistry
• Environmental Science

Background:

• Activated sludge microorganisms, such as Zoogloea ramigera, can form flocs.
• Sudanophilic granules have been observed in these organisms during flocculation.

Purpose of the Study:

• To identify the sudanophilic granules in Zoogloea ramigera.
• To investigate the synthesis and accumulation of these granules.
• To explore the potential role of these granules in flocculation.

Main Methods:

• Isolation and cultivation of Zoogloea ramigera from activated sludge.
• Extraction of granules using chloroform and precipitation with ether.
• Identification of the polymer via physical, chemical, and infrared spectral analyses.
• Analysis of polymer synthesis under varying nutrient conditions.
• Correlation of polymer accumulation with optical density and glucose uptake.

Main Results:

• The granules were identified as poly-beta-hydroxybutyric acid (PHB).
• PHB constituted 12.0% to 50.5% of the dry cell weight.
• PHB accumulated when cultures were enriched with carbon and energy sources, but not under growth-limiting conditions.
• Intracellular PHB concentration was directly proportional to optical density and glucose uptake.

Conclusions:

• Zoogloea ramigera synthesizes and accumulates significant amounts of PHB.
• PHB accumulation is dependent on the availability of carbon and energy sources.
• PHB accumulation is linked to increased cell growth and glucose uptake.
• PHB accumulation may serve as a mechanism contributing to the flocculation of Zoogloea ramigera.