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The characterization and description of representatives of ‘G’ bacteria from activated sludge plants
Author(s) -
Blackall L. L.,
Rossetti S.,
Christensson C.,
Cunningham M.,
Hartman P.,
Hugenholtz P.,
Tandoi V.
Publication year - 1997
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.1997.00176.x
Subject(s) - biology , bacteria , microbiology and biotechnology , activated sludge , 16s ribosomal rna , phylogenetic tree , rhodobacter , genetics , gene , sewage treatment , mutant , engineering , waste management
The name Tetracoccus cechii is proposed for two strains of the tetrad arranged cocci, previously known as ‘G’ bacteria, which were isolated from laboratory scale activated sludge plants in the Czech Republic and in Italy. They were morphologically, phenotypically and phylogenetically characterized and found to comprise a novel lineage in the alpha‐3 group of the proteobacterial phylum in the domain Bacteria . The strains are Gram‐negative and produce intracellular inclusions of poly‐β‐hydroxybutyrate. Although commonly seen in activated sludge mixed liquor as cocci 1–2 μm in diameter, arranged in tetrads, in pure culture they can also grow in amorphous aggregations and the cells are generally more variable in their size and shape with coccobacilli as well as cocci being present. They are not able to grow phototrophically, nor can they reduce nitrate beyond nitrite nor grow anaerobically. The closest phylogenetic neighbours of T. cechii are Rhodobacter sphaeroides and R. capsulatus which are 93% similar by 16S rDNA comparison. Tetracoccus cechii is oxidase‐ and catalase‐positive, non‐motile and has an optimal growth temperature between 25° and 35°C. The 16S rRNA of T. cechii has a 21 nucleotide deletion in the V9 region ( Escherichia coli positions 1258–1278) and this feature is a unique molecular synapomorphy in the alpha‐3 group.