Molecular detection and diversity of medium-chain-length polyhydroxyalkanoates-producing bacteria enriched from activated sludge.
OBJECTIVE
Knowledge of the species composition of complex bacterial communities is still very limited. The main objectives of this study were to identify medium-chain-length polyhydroxyalkanoates (mcl-PHAs)-producing bacteria from activated sludge fed with methanol as well as to characterize their PHA operon.


RESULTS
The identification was based on PCR amplification of mcl-PHA synthase gene fragments. In the analysed sample, four isolates possessing mcl-PHA synthesis systems were distinguished. The results of a 16S rDNA sequence analysis revealed that three strains belonged to Pseudomonas species and the fourth one was characterized as Comamonas testosteroni.


CONCLUSIONS
The results of this study indicate that the PCR-RFLP approach is an excellent way to identify mcl-PHA-synthesizing micro-organisms. The discovery of 4 genetic variants, among the 20 analysed, demonstrates that microbial diversity of activated sludge is high and thus offers a great opportunity for the discovery of novel gene forms.


CONCLUSIONS
An important discovery of this study is that C. testosteroni could harbour mcl-PHA operon. Moreover, the results obtained indicate that PHAs synthesis ability can be spread by horizontal gene transfer. The results of a comparative phylogenetic analysis revealed that mcl-PHA-synthesizing bacteria can be divided into Pseudomonas fluorescens and Pseudomonas aeruginosa groups.
Ciesielski
S
S
Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland. slavcm@uwm.edu.pl
Cydzik-Kwiatkowska
A
A
Pokoj
T
T
Klimiuk
E
E
D000217:Acyltransferases / Q000235:genetics; D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis*; D017753:Ecosystem; D005285:Fermentation; D014644:Genetic Variation; D000432:Methanol; D008969:Molecular Sequence Data; D009876:Operon; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D014871:Water Microbiology
D004269:DNA, Bacterial; D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase; D000432:Methanol