Exploration and effectiveness test of the potassium solvent bacteria originating from limestone mountain of Bahorok Langkat

Abstract

Plants need potassium in large quantities. The dissolved potassium concentrations are only 1-2%, meanwhile more than 90% of potassium in the soil is in the form of soluble rock. Potassium solvent bacteria facility in dissolving K. From several studies, potassium solvent bacteria can be found in limestone quarries. One of the limestone mountains in North Sumatera is the mountains in Laudamak village, Bahorok sub-district, Langkat District. This study aimed to obtain the potassium solvent bacteria and examine their potential of superior isolates from Bahorok Langkat mountain limestone. Sampling was conducted by the purposive random sampling method which was in two different locations and two different soil depths, namely on the mountain slop and foot of the limestone mountain. The ability to dissolve K was tested qualitatively by calculating the dissolution index (IP). The hypersensitivity test was carried out on tobacco leaves. The result showed that 18 isolates found from 10 soil sample from Bahorok Langkat limestone mountain were able to dissolve K in the Aleksandrov medium, there were 11 isolates that were able to dissolve K and 11 of selected isolates were not pathogenic to plants.

Isolation and molecular characterization of potassium-solubilizing bacteria from limestone mountain of Bahorok, Langkat District, Indonesia

“…Generally, all selected bacteria found in the limestone mountain of Bahorok Langkat could dissolved K (Bangun et al 2020). The selection process was divided into two stages: Bench-scale studies, a selection process that tests K dissolution in the laboratory on solid Aleksandrov media, and Pilot-scale processes, which test K solubilization on soil media.…”

“…This study consisted of three interconnected stages, which began with the selection of 11 KSB (Table 1) from a previous study by Bangun et al (2020). Eleven selected KSBs were subjected to bench-scale studies (dissolving K in solid media in the laboratory) using the dissolution index method.…”

“…The current study employed 11 (Table 1) types of KSB, which were selected from a previous study by Bangun et al (2020) and tested for their dissolution index on Aleksandrov solid media in a laboratory setting using a non-factorial, completely randomized design (CRD). These KSB were: KSB.PA1, KSB.PA2, KSB.PA3, KSB.TA1, KSB.PB1, KSB.TB1, KSB.TB2, KSB.TB3, KSB.TB4, KSB.TB5, and KSB.TB6 from (Tabel 1).…”

“…(Sarikhani et al 2018), and members of Enterobacteriaceae, Pseudomonadaceae, Bacillaceae, Micrococcaceae (Sharma et al 2022), that can dissolve K in Aleksandrov media. Previous research conducted by Bangun et al (2020) has found that 11 KSB isolates were isolated from soil samples around Bahorok Langkat limestone area that were capable of solubilizing K in Aleksandrov media. The mechanism of K solubilization was characterized by a decrease in pH in the growth medium, indicating the potential mechanism of mobilizing K from crystal-bound forms through the production of organic acids (Ghosh et al 2023).…”