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From Biology-Online Dictionary | Biology-Online Dictionary
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noun, plural: zoogleas, zoogleae

A jelly-like gram-negative aerobicrod-shaped bacterium that aggregates on gelatinous matrices and composed of extracellular polymer strands of polysaccharides.


Zoogloea comes from the Greek word and translated as “living glue.” It is an aerobic,chemoorganotrophic, non-spore forming bacteria that normally exhibit as afree living in organically polluted fresh water and waste water at any range of treatment.

These bacteria are set in sharply distinguished columns which stick out to form clusters that comprise the recognized growth form. Its cells are non-pigmented in which the older one may beencapsulated.

These organisms arestrong oxidase and weak catalase positive. The formations of flocs andfilms in liquid media at later period of growth are eminent by fingerlike morphology. Mature colonies are firm and solid that can be easily lifted from agar surface with a needle. Zoogloeas are not particular in itsnutrition thus, can be easily cultured on a variety of organic carbon sources in a simple medium.

Ecologically, this organism plays an essential part in wastewater treatment through its capacity to lowerbiological oxygen demand and by upholding the arrangement of sludge deposits. It is known that typical sludge bacteria are responsible for the formation of sludge flocs wherein these compacted flocs settled at the bottom of the treatment tanks tohelp out in purification process.

Word Origin: zoo= “living animal” + gloea = “glue

Scientific Classification:

  Domain Bacteria
    Phylum Proteobacteria
      Class Betaproteobacteria
        Order Rhodocyclales
           Family Rhodocyclaceae
             Genus Zoogloea

Related terms:

zoogloeal (adjective)