Eco-Physiological and Biological Characterization of Phosphate Solubilize Bacteria Isolated from Low pH Soils of Tigray Region

Phosphate solubilize bacteria plays a key role on an increasing bioavailability of the insoluble phosphates through the action of releasing organic acids. The research was conducted on soil microbiology laboratory to evaluate the selected physiological and biochemical characteristics of the isolated strains. Series of research methodology was used to evaluate eco-physiological, morphological and biochemical tests. The nominated isolates show gram negative, mucous texture and all of them grown well at pH 6 and 7, 15-35℃ temperature and 1-1.5% salt concentration (Na Cl2). Promising result was observed from 1.5mg/l and 3.0mg/l of MnSO4 and 0.25mg/l ZnSO4. Regarding to carbohydrate utilization, all of the tested isolates were utilized the tested carbon source. Promising result was obtained from phosphate solubilization, the highest solubilization index was recorded from IS-B (2.21) followed by IS-E (2.18). The pull-down of pH from 7.0 to 4.75 shows that the ability of the isolated strain to release phosphates. Therefore, the authors concluded that, effective phosphate solubilize bacteria recommended for acidic soils particularly for the study sites to enhance phosphorus uptake to plant growth.