Environmental distribution of Zoogloea strains

Abstract

Enrichment culture techniques were employed to examine the environmental distribution of fingered zoogloea (FZ)-forming bacteria. FZ were detected in surface films of cultures started with various wastewaters, polluted pond and stream waters, duck feces, garbage disposal wastes and fish aquarium waters, but were not observed in cultures started with food scraps or soils. According to most probable number estimates of FZ-forming bacteria and total populations formed in enrichment cultures. less than 0.01% of the viable bacterial population in domestic wastewater and aerobic mixed liquor suspended solids (MLSS) contained the specific zoogloea-forming bacteria. However, FZ-forming bacteria were present in 10-fold greater concentrations in MLSS than in the raw wastewater solids. An isolation procedure, employing an inoculum of concentrated and sonically treated washed FZ yielded 70 strains of zoogloea-producing bacteria, 61 of which formed typical finger-like zoogloeae in pure culture. Isolates were removed also by direct streaking of enrichment culture films. The bacteria were isolated from enrichment cultures started with raw wastewaters, polluted pond waters, greenhouse drainage, fish aquarium water and duck feces. The zoogloea-producing strains were gram negative, motile rods possessing catalase and oxidase and the ability to denitrify, hydrolyze gelatin in plates and meta cleave m-toluic acid. Certain biochemical activities were located among isolates in relation to the various habitats from which they originated. The bacteria were considered to be strains of Zoogloea ramigera.