ISOLATION AND SELECTION OF SILICATE SOLUBILIZING BACTERIA FROM MANY VARIOUS HABITATS

Abstract

Silicate solubilizing bacteria in soil play a very important role in plant protection and in promoting tolerance capacity of plants againsting abiotic-stresses. The objects of this study was to isolate, select and identify silicate solubilizing bacteria from soil, earthworm and earthworm’s feces samples within the Mekong Delta region of Vietnam. Soil extract agar media containing magnesium trisilicate 0.25% was used to isolate bacteria. Soluble silicate concentration was determined as Molybdenum Blue Colorimetry method. The results of the study indicated that twenty-five out of two hundred and fifty isolates showed their highly silicate solubilizing capability and ranged from 10.63 to 55.17 mg.L^-1. The best five silicate solubilizing bacteria were found to be TCM_39 (52.02 mg.L^-1), PTST_30 (51.72 mg.L^-1), MCM_15 (39.08 mg.L^-1), LCT_01 (35.44 mg.L^-1) and RTTV_12 (33.84 mg.L^-1). Based on the results of 16S rRNA sequences, these five bacterial strains were genetically and relatively identified as Ochrobactrum ciceri TCM_39, Olivibacter jilunii PTST_30, Microbacterium neimengense MCM_15, Klebsiella aerogenes LCT_01 and Citrobacter freundii RTTV_12.