Characterization of thermostable antimicrobial and anti-inflammatory protein from marine Bacillus sp

Marine microorganisms are rich in bioactive compounds having biotechnological significance. Hydrothermal vents are specifically home to unique microbial communities that have the ability to produce diverse compounds with therapeutic potential. This study aimed to isolate and characterize bioactive proteins from marine Bacillus sp. with antibacterial and anti-inflammatory properties and to evaluate their efficacy.

Bacillus sp. isolated from hydrothermal vents, have been grown optimally, with the partially purified extracellular protein fraction separated by ammonium sulfate precipitation and Sephadex G-10 gel filtration. The antimicrobial property was determined against the Methicillin-resistant Staphylococcus aureus (MRSA) and Vibrio vulnificus, with temperature stability studies conducted on the proteins. Zebrafish infection assays, together with lipopolysaccharide (LPS) challenges, served to determine the biological activity.

A thermostable protein with a molecular weight of ⁓ 55 kDa showed strong inhibitory effects against MRSA and V. vulnificus. In the infection models using zebrafish, administration of the protein extract led to a substantial increase in survival rates (P < 0.01). Besides, a reduction in mRNA expression of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) was observed using RT-PCR analysis.

The thermostable Bacillus sp. protein exhibited both antibacterial and anti-inflammatory properties, indicating its potential for scale-up and biotherapeutic use.