Reclassification of a cyclodextrin glycosyltransferase-producing bacterium of industrial application

CAMINATA LANDRIEL SOLEDAD; CASTILLO DE LAS MERCEDES JULIETA; CANTERO MARIA JOSE; RODRIGUEZ GASTON JORGELINA ANDREA; TABOGA OSCAR ; FERRAROTTI SUSANA ALICIA; COSTA HERNÁN

Mar del Plata

Congreso; LI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Cyclodextrin Glycosyltransferase (CGTase), a glycoside hydrolase, catalyzes starch conversion into cyclodextrins and other industrial products such as maltooligosaccharides. We have isolated a CGTase from a soil bacterium which had been classified as Bacillus circulans based on its phenotypic profile. The 16S rRNA gene is widely used for phylogenetic studies; however, its use is limited due to intragenomic heterogeneity and low discriminative power at related genus. In addition, housekeeping genes are used. The aim of this work was to identify this CGTase-producing bacterium by molecular phylogenetic analysis of the 16S rRNA gene and the housekeeping genes dnaK, gyrB, recA, rpoB and tufA. All genes were amplified by PCR and sequenced. The substitution model was inferred with jModeltest. Phylogenetic trees were reconstructed by Maximum Likelihood (ML) and Bayesian Analysis methods using PAUP* and Mr. Bayes, respectively. For ML, the robustness was estimated by 500 replicates of non-parametric bootstrap. According to the results, the strain of Bacillus circulans was grouped within the genus Paenibacillus. In addition, Paenibacillus molecular signatures in the 16S rRNA and rpoB genes were found in the respective sequences of Bacillus circulans. We conclude that the bacterium under study must be reclassified within the Paenibacillus genus, with subsequent definition of specie.