Fig. 2

Isolation, screening, and identification of ALP-producing bacteria. a Isolation and qualitative screening of CaCO₃-solubilizing and ALP-producing bacteria. b Phylogenetic tree based on 16S rDNA gene sequence analysis showing the relationship of B. licheniformis strain ALP3 with reference strains (NCBI GenBank) constructed using the neighbor-joining method with the aid of MEGA X program. c Cultural feature of B. licheniformis strain ALP3 agar plate. d SEM micrograph of B. licheniformis strain ALP3 showing cell morphology at a magnification of 5000 and ×10,000  with 15 kv. e Gram-stain of the B. licheniformis strain ALP3 (using magnification, oil lens ×100)