Isolation and Molecular Identification of Klebsiella Pneumoniae Strains, Producing Diols from Glycerol
Résumé
ABSTRACT Among the promising bulk chemicals, 1,3-propanediol (1,3-PD) and 2,3-butanediol (2,3-BD) are two bio-based diols, which have a wide range of applications in cosmetic and food industry, as antifreezes, lubricants, fuel additives, as well as in the production of polymers. The possibility to obtain diols from the waste glycerol is topical by two reasons. First, the waste glycerol is received in large amounts during the manufacturing of biodiesel from plant oils and is inexpensive and renewable source. On the other hand, the glycerol's liberation in the environment is connected with serious ecological problems. In this study is reported the isolation of three novel strains G9, G31 and G46, capable to convert glycerol into high amounts of 1,3-propanediol (1,3-PD) and 2,3-butanediol (2,3-BD). They were examined by classical microbial tests and by the genetical approach of 16S rDNA sequencing. The strains' physiological and biochemical features indicated their most possible affiliation to the species Klebsiella pneumoniae: they were facultative anaerobes, oxydase-negative and catalase-positive, did not grow at 10 ºC, didn't generate H2S and were able to ferment the all typical for the species carbohydrates. The sequencing of 16S ribosomal RNA gene confirmed the affiliation of G9, G31 and G46 to Klebsiella pneumoniae subsp. pneumoniae. The sequence comparison with the GenBank data (NCBI) showed 99% sequence identity of G31 with the type strain K. pneumoniae subsp. pneumoniae ATCC 13883T. G9 and G46 were closely related (99% 16S rDNA identical nucleotides) to another ATCC species: MGH 78578 and to the known as excellent glycerol fermenting strain K. pneumoniae TUAC01. The other Klebsiella strains, known as glycerol consuming - K. oxytoca strain 17 and K. planticola strain DR3 were quite phylogenetically distant from ours and formed a separate branch of the phylogenetic tree.