Estimation of the Intrinsic Biodiversity among Poly(3-Hydroxyalkanoates) Degrading Streptomycetes using Gas Chromatographic Analysis of Fatty Acids

Abstract

One hundred and twenty three poly(3-hydroxyalkanoates) degrading streptomycetes (referred to as PHA strains) from soils, composts, natural waters, and some other sources were characterized by gas chromatographic analysis of their methylated cellular fatty acids. They were compared to reference strains of the genera Streptomyces (46 strains) and Streptoverticillium (9 strains) by numerical analysis. Saturated iso - and anteiso -branched fatty acids of between 14 and 18 carbons constituted the major components in the fatty acid profiles of most of the strains. In the dendrogram, obtained by unweighted average linkage clustering of the Euclidean distances Δ, calculated between each pair of fatty acid profiles, all strains were linked at Δ = 43. At Δ = 11, 18 clusters, consisting each of 2 to 63 strains, could be delineated, and 16 strains remained unclustered. The clusters could also be recognized by principal-component analysis, although small overlaps between some clusters were evident. Most clusters could be differentiated from each other by their fatty acid compositions. The PHA strains were scattered over 14 different clusters, 11 of which also contained reference strains, and 9 PHA strains remained unclustered. In addition to the PHA strains, 29 of the 46 reference strains of Streptomyces were also shown to degrade poly(3-hydroxybutyrate) in vitro . Poly(3-hydroxybutyrate-co-10%3-hydroxyvalerate) was degraded in vitro by all 56 PHA strains tested. The study demonstrates the biodiversity of streptomycetes involved in the degradation of poly(3-hydroxyalkanoates) in different habitats. The numerical analysis of fatty acid profiles confirms the homogeneity of the Streptomyces albidoflavus group, and the heterogeneity of the Streptomyces cyaneus and Streptomyces anulatus groups, and supports the reunification of the genera Streptomyces and Streptoverticillium .