Isolation and identification of potassium‐releasing bacteria in soil and assessment of their ability to release potassium for plants

Abstract

Summary The application of potassium (K)‐releasing microorganisms is a promising approach for increasing K availability in soil. The objectives of this study were to isolate and characterize the K‐releasing bacteria (KRB) and to evaluate their contribution to the solubilization of K from muscovite and biotite, and to the assimilation of released K by tomato in a pot culture experiment. Soil samples were screened in both solid and liquid Aleksandrov media to isolate bacteria with the potential to release K from biotite and muscovite. Our results from in‐vitro experiments revealed that more K was released in treatments with KRB than in the uninoculated media (control). Under the best conditions an increase of 188 and 127% was obtained for biotite and muscovite, respectively; among the isolates with the largest releasing ability it was 49 mg l−1. The most efficient bacteria were identified as the Pseudomonas genus. Results of the pot culture experiment showed that the concentration and content of K in plant tissue were considerably more than those in any of the controls with no living organisms present. Results revealed that significantly more biomass was accumulated and K acquired in most pots treated with bacterial strains than in the control, especially for Pseudomonas sp. strain S10‐3. This treatment increased K concentation and content by more than 50 and 70%, respectively, in tomato aerial tissue. Further research is necessary to examine the effects of these bacterial strains on the mobilization of K‐bearing minerals under field conditions. Highlights The aim was to determine if bacterial isolates can accelerate K release from micas for plants. We investigated the potential of some isolated bacteria to solubilize K from muscovite and biotite. Identification of efficient isolates showed that KRB belonged to the Pseudomonas genus. Pseudomonas sp. strain S10‐3 increased K concentration in tomato aerial tissue by more than 50%.

Spatial distribution and identification of bacteria in stressed environments capable to weather potassium aluminosilicate mineral

“…Silicate weathering isolates have been obtained from nonagricultural sites like ceramic industrial soil, weathered material of Rock Mountain, Cirebon quarry and Red soil of Poyang lake [15,40,45,46]. There are few reports available in the literature on the screening of small subset of bacteria isolated from one or two niches or crops for mineral weathering [7,13,16,22,41]. However, no concerted effort has been made to screen the diversity of bacteria recovered from stressed environments of the country for their ability to weather silicate mineral.…”

“…At present, most of the reported isolates exhibiting mineral weathering efficiency belong to genus Bacillus. Besides, few reports are available which describe mineral weathering potential of isolates belonging to genus Alcaligenes, Arthrobacter, Acidithiobacillus ferrooxidans, Paenibacillus, Enterobacter, Serratia and Burkholderia, while fungi belonging to genus Aspergillus and Penicillium have also been reported to weather silicate mineral [7,12,22,27,44,47,48]. These microorganisms have been reported to release potassium in accessible form from potassium-bearing minerals in soils.…”

“…Among all the SWB analysed, weathering efficiency in liquid medium ranged from 1.9 to 72.8 μg mL −1 of available K from potassium aluminosilicate mineral. In general, the literature reports the range to be 0.5 to 76.0 μg mL −1 of available K [7,12,13,22,41,45]. From Sambhar salt lake, few halophilic or halotolerant SWB were identified like Bacillus halodurans, Ammoniphilus sp., Halomonas sp.…”

“…The biological process of release of K from minerals involves the activity of microorganisms. In the recent years, reports have been published on the utilization of silicate mineral weathering bacteria for crop improvement [1,[6][7][8][9][10][11]. Initially, only species of Bacillus were reported to weather silicate mineral.…”

Development and Characterization of Efficient K-Solubilizing Rhizobacteria and Mesorhizobial Inoculants for Chickpea

“…Our results confirmed the efficacy of the KSB isolation approach as both strains with highest halo zone formation were able to solubilize the highest amount of K among rest of the strains (Table 4). Numerous reports have shown the tendency of some microbes to solubilize the insoluble K caused by bacterial metabolic activity, resulting in the dissolution of K [16,46].…”