Isolation and genetic diversity of mineral-solubilizing bacteria of different weathered potassium-feldspars

Abstract:

Abstract: [Objective] We isolated and characterized potassium-bearing mineral-solubilizing bacteria from the surfaces of weathered feldspar as well as soil samples. [Methods] We isolated cultivable mineral-solubilizing bacteria by plating and screening from the surfaces of different level of weathered feldspar as well as soil samples. We characterized bacteria regarding their ability of releasing Si from feldspar samples and further classified by amplified rDNA restriction analyses (ARDRA). Twelve typical bacterial strains were identified by 16S rDNA sequence analysis. [Results] Thirty-five Si-releasing bacteria were isolated from the surfaces of weathered feldspar and soil samples and classified by ARDRA in 11 different operational taxonomic units (OTU) at the similarity level of 60%, belonging to 5 major phylogenetic groups, 6 families, and 7 genera (Pantoea, Pseudomonas, Serratia, Agrobacterium, Sphingobacterium, Exiguobacterium, and Microbacterium). Pantoea, Pseudomonas and Serratia were the dominant groups. Inoculation with the isolates was found to increase the Si in the solution by 101~206% compared to the control. [Conclusions] Different mineral- solubilizing bacteria inhabited in different weathered K-feldspar surfaces and soils in the potassium mine. γ-Proteobacteria might play an important role in the process of K-feldspar weathering.