Isolation and identification of poly(3-hydroxyvalerate)-degrading strains of Pseudomonas lemoignei.

Abstract

By using selective enrichment of polyhydroxyalkanoate-degrading bacteria and poly(3-hydroxyvalerate)-containing granules from Chromobacterium violaceum as the carbon source, 10 new Pseudomonas lemoignei strains were isolated; these strains were able to degrade poly(3-hydroxyvalerate), as well as poly(3-hydroxybutyrate), in vitro. The new isolates were characterized and identified by comparing them with P. lemoignei LMG 2207(T) (T = type strain). Like P. lemoignei LMG 2207(T) cells, the cells of the 10 new isolates contained mainly hexadecenoic, hexadecanoic, octadecenoic, and dodecanoic acids, as well as hydroxylated fatty acids, and exhibited respiration in the presence of methylpyruvate, 3-hydroxybutyrate, and 4-hydroxybutyrate, but not in the presence of the 92 other carbon sources included in Biolog GN microplates. The protein patterns of the new isolates were almost identical to each other and very similar to the protein pattern of P. lemoignei LMG 2207(T). Some of the new isolates, but not P. lemoignei LMG 2207(T), contained megaplasmids that were about 200 kbp long. The 16S ribosomal DNA genes of strain A62, a representative of the 10 new isolates, and of P. lemoignei LMG 2207(T) exhibited more than 0.99 sequence similarity. The DNA-DNA reassociation value for two representative strains was 100%, and the levels of DNA-DNA reassociation between these strains and the type strain were 60 and 61%. The taxonomy of P. lemoignei is briefly discussed.