Isolation, characterization and identification of polyhydroxyalkanoate-accumulating bacteria from activated sludge

Wen-Tso Liu, Takashi Mino, Tomonori Matsuo, Kazunori Nakamura

Research output: Contribution to journalArticlepeer-review


Two novel gram-positive bacteria capable of accumulating poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(3HB-co-3HV)] were isolated from an anaerobic-oxic activated sludge system fed with acetate. Strains Lpha5 and Lpha7 are motile cocci, 1-2 μm in diameter, occurring singly or in pairs. These isolates have doubling times ranging from 0.4-1.7 d and can accumulate in high levels of poly(3HB-co-3HV) (up to 44.7% of cell dry weight) when grown on complex media. Furthermore, these two strains exhibited the rapid substrate uptake and accumulation of storage granules as observed in situ. Under aerobic conditions, about 14.4% (cell dry weight) polyhydroxyalkanoate and 82% (carbon dry weight) cellular carbohydrate were produced from acetate and glucose, respectively. Under anaerobic conditions, poly(3HB-co-3HV) and cellular carbohydrate accumulated when glucose but not acetate was fed. The result of analysis of 16S rRNA sequence revealed that both strains belong to the gram-positive high-G+C group, but are significantly different from their closest phylogenetic relatives, Dermatophilus sp. and Terrabacter sp., to warrant classification as a new species.

Original languageEnglish (US)
Pages (from-to)494-500
Number of pages7
JournalJournal of Bioscience and Bioengineering
Issue number5
StatePublished - Jan 1 2000
Externally publishedYes


  • Activated sludge process
  • Biological phosphorus removal
  • Polyhydroxyalkanoate
  • Polyphosphate

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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