Received: 19-09-2022 / Accepted: 20-12-2022
The objective of this study was to select bacterial strains with strong nitrogen fixation and IAA biosynthesis ability. Five strains with both activities were selected from 32 tomato soil samples collected in Thai Nguyen province. The strain MN26 was selected for its strongest nitrogen fixation and IAA biosynthetic activity, corresponding to 20.82 µg/ml NH4+when grown on Ashby medium and 77.23 µg/ml IAA on Ashby medium supplemented with 0.1% L-Tryptophan. Based on 16S rRNA gene sequence analysis data and phylogenetic tree, the strain MN26 could be considered as a new species candidate belonging to the genus Flavobacteriumwith scientific name as Flavobacteriumsp. MN26. Results of culture characterization showed that Flavobacteriumsp. MN26 was capable of producing 8 enzymes (phosphatase alcaline, leucine arylamidase, valine arylamidase, trypsine, phosphatase acid, naphtol-AS-BI-phosphohydrolase, -galactosidase, and D-glucosidase) and capable of assimilation of various carbon sources including D-glucose, L-arabinose, D-mannose, D-mannitol, D-maltose, L-rhamnose, D-ribose, inositol, D-saccharose, N-acetyl-glucosamine, malic acid, phenylacetic acid, potassium gluconate, sodium acetate and trisodium citrate. The strain MN26 was capable of producing indole but incapable of converting nitrate to nitrite.