A new nocardioform actinomycete was isolated by filament micromanipulation during the course of a study into foaming in activated sludge plants in Australia. It constitutes the second most prevalent foaming organism in Australia after Nocardiu amarae. These two foaming organisms can be differentiated morphologically, biochemically and chemotaxonomically. The microscopic appearance of the filaments of the new taxon resembles a pine tree. The filaments are Gram-positive, non-acid-fast, non-motile, non-sheathed and about 0.5-1 -0 pm in diameter. On a complex medium, the colonies are orange, opaque, macroscopically dry and friable, microscopically moist and shiny, with a pasty texture and an entire edge. The strains are positive for catalase, oxidase and urease and are oxidative in their metabolism of glucose. No strain could degrade hypoxanthine, xanthine, tyrosine, casein, gelatin or aesculin and none could grow with lysozyme. The strains contain peptidoglycan type Aly, cell wall type IV, whole cell sugar pattern type A, phospholipid type PII, menaquinones o-cyclo-MK-8 (H4), fatty acids comprising straight chain saturated and unsaturated acids and tuberculostearic acid, and mycolic acids with 58-64 carbons containing substantial amounts of unsaturated chains in the 2-position. The name Nocardiapinensis has been chosen for the new taxon because of the pine tree like appearance of the organism on microscopy. The type strain, UQM3063, is deposited at
The formation of extensive, biological foams or scums on the liquid surfaces of domestic activated sludge plants in Australia was investigated. A survey of the problem in Queensland and Australia was carried out; the dominant organisms in the foam were isolated and identified; their physiology was investigated and the intrinsic reasons for foam formation were explored in the laboratory. Foaming in activated sludge plants was found to be a significant problem in Australia. Greater than 90% of plants in Queensland have experienced biological foaming episodes, whilst in 38% of the plants the problem was continuously present. Nocardia amarae and a newly described actinomycete Nocardia pinensis were the dominant organisms isolated from the foam. Plants that contained N. pinensis in the scum were found to be operated at long sludge ages. Although technical problems were experienced with chemostat methodology when applied to N. amarae, a limited amount of information about their physiology was obtained. The cells of N. amarae were found to be hydrophobic and a surfactant(s) was produced in culture. These are properties which suggest an explanation for the mechanism of foam formation based upon adsorptive bubble separation theory.
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