ABSTRACT
Aims: Potassium is an essential macronutrient for the growth and development of plants. Most of potassium in the soil presented in mineral forms or non-exchangeable forms which are not available for plants. The microbial activity facilitated to release of mineral forms or non-exchangeable potassium to the exchangeable or water-soluble. This study was aimed to isolate, select, and characterize of the selected potassium solubilizing bacteria from limestone mining area in Palimanan, Cirebon Quarry. Methodology and results: Isolation and selection of bacteria was done based on potassium dissolving index in Aleksandrov media containing feldspar, non-exchangeable potassium. Thirty seven isolates of potassium solubilizing bacteria were obtained in this study. Three isolates showed higher dissolution index, namely KQC.4B.1, KQC.5A.4, and KQC.5C.5. All of isolates were Gram negative bacteria, short-rod formed, and able to dissolve potassium concentration on 10th and 20th days. The three isolates showed 99.9% physiologically similar with Burkholderia cepacia. Futhermore by using 16S rRNA gene identification, isolate KQC.5C.5 closely related with B. cepacia with 99% identity. The application of isolate KQC.5C.5 on soil showed that the isolate was able to release the solution K formed after 10th day incubation. Conclusion, significance and impact of study: Potassium solubilizing bacteria (B. cepacia) could use as a biological fertilizer for providing potassium which is available to plants grown on reclamation area of limestone quarry.