Isolation and probiotic characteristics of Bacillus licheniformis HF-07107 with high adhesion from common carp （Cyprinus carpio L.）

【Objective】To isolate and characterize Bacillus licheniformis strains with high adhesion from common carp and comprehensively assess its probiotic potential as feed additives for common carp culture，which provided reference for the application of host-derived probiotics in common carp culture.【Method】Potential probiotics were isolated from intestinal tract and its contents of healthy common carp. The isolated strains were identified by morphological characteristics， physiological and biochemical characteristics，16S rRNA sequence comparative analysis and phylogenetic tree construction. The adhesive ability of the isolated strain was evaluated by detecting its self-aggregation ability，co-aggregation ability and hydrophobicity in organic solvents.The acid resistance，bile salt tolerance and high temperature resistance，as well as its antibacterial ability to Aeromonas hydrophila and Staphylococcus aureus and its sensitivity to antibiotic tablets were detected to determine whether the strain had probiotic properties.【Result】Strain HF-07107 were isolated from intestinal tract and its contents of healthy common carp. The morphological characteristics of strain HF-07107 showed that it was spore-producing，Gram-positive，rod-shaped，and its physiological and biochemical identification results were consistent with those of Bacillus licheniformis. The similarity of 16S rRNA sequence between the strain HF-07107 and B. licheniformis ATCC 14580^T was 99.31%，and strain HF-07107 was in the same cluster with B. licheniformis in the phylogenetic tree. The strain HF-07107 was comprehensively identified as B. licheniformis. The strain had a high self-aggregation ability of 72.92%，co-aggregation ability with Edwardsiella tarda and A. hydrophila（96.15% and 60.23%）and high hydrophobicity value with toluene，xylene，chloroform and n-hexane（more than 90.00%），indicating strain HF-07107 had high adhesion. At the same time，strain HF-07107 could tolerate pH 2.0，0.3% bile salt and 90 ℃ high temperature environment，inhibit the growth of A. hydrophila and S. aureus and was sensitive to bactrim，amikacin，ciprofloxacin，gentamicin，erythromycin，tetracycline，cefazolin and norfloxacin.【Conclusion】B. licheniformis HF-07107，a potential probiotic from common carp with high adhesion characteristics，can tolerate adverse environment，and inhibit the growth of pathogenic bacteria. Therefore，it can be used as a host-derived probiotic in aquaculture.