A novel high dextran yielding Weissella cibaria JAG8 for cereal food application.

摘要

A new isolate from apple producing dextransucrase and dextran was characterized by morphological, biochemical and 16S rDNA analyses. The short rod bacterium that was identified as Weissella cibaria (GenBank accession number KC110687) was Gram-positive, non-motile, catalase-negative and vancomycin-resistant. The max. dextransucrase activity (5.8 U/ml) and dextran concn. (38 mg/ml) were observed at 24 degrees C after 12 h of growth under static conditions. The PEG-400 fractionation of partially purified enzyme showed a specific activity of 20.0 U/mg and displayed a single homogenous band of 177 kDa by SDS-PAGE (7.5%). The dextran was enzymically synthesized using dextransucrase and substrate sucrose. Dextran was purified by alcohol precipitation for further characterization. The rheological analysis of dextran elucidated a non-Newtonian pseudoplastic behaviour. 1H and 13C NMR analyses revealed the fact that the dextran contained D-glucose monomer with 93.0% of alpha(1 rightwards-arrow 6) linear and 7.0% of alpha(1 rightwards-arrow 3) branched linkages.