Evaluation on multi-trait activities of Azotobacter spp. from various water samples in Mandalay environments

Fourteen water samples were collected from different locations of Mandalay and Kyaukse Township. Among them, eight bacterial isolates named A1 to A8 were nominated as Azotobacter according to their colonial morphology, microscopic morphology, and pigment production. According to the biochemical characteristics and sequence analysis of isolated bacteria, they were Azotobacter chroococcum, Azotobacter vinelandii, and Azotobacter beijerinckii. The phosphate solubilizing of these isolates was observed from 2.3 to 2.6 SI, and A4 had the highest solubility index. The potassium decomposing of these isolates was observed 2.5 to 3.8 SI, and A6 and A8 had the highest K-decomposing activity. The zinc solubilizing of these isolates was observed at 2.3 to 3.5 SI, and A3 had the highest zinc solubilizing index. Screening methods showed that all eight strains have nitrogen fixing activity and Indole Acetic Acid (IAA) producing activity. The antagonistic activity of all isolated strains was also found against Pythium sp. and Fusarium oxysporum. The isolated Azotobacter sp. can be used as biofertilizer in the agriculture sector, which can increase crop yields and enhance soil fertility according to their plant growth promoting activities