Characterization and in Silico analysis of outer membrane proteins in halophilic and halotolerant bacteria which isolated from Qarun Lake solar salterns

This study included the isolation and characterization of halophilic and halotolerant bacteria from the solar salterns of Qarun Lake, Fayoum, Egypt. A total of seventeen bacterial strains were isolated, of which fifteen were identified as halophilic and two as halotolerant, based on their salt growth requirements. Phylogenetic analysis revealed that the isolates clustered into four distinct groups, with members of the phylum Firmicutes representing the dominant group (47.06%). Biochemical characterization indicated that 52.94% of the isolates were Gram-negative, and all exhibited motility and catalase activity. Salt tolerance assays confirmed that two isolates could grow without added salt, while the remaining strains required salt for growth, supporting their classification as halotolerant and halophilic, respectively. Notably, 70.59% of the isolates were classified as extremely halophilic. Based on 16S rDNA sequence analysis, the closest related strains were identified from GenBank, and the functional potential of their outer membrane proteins (OMPs) was predicted. Draft genome analysis of 88.24% of the isolates revealed the presence of genes encoding various functional proteins, including those involved in adhesion, secretion, enzymatic activity, and membrane transport, although some protein functions remain uncharacterized. This study contributes to the understanding of halophilic microbial diversity in Egyptian hypersaline environments and provides insights into their potential functional roles. Future research will aim to explore their biotechnological applications and ecological significance.