# Marine-Derived Bacillus Biosurfactants as Potential Antibacterial and Antibiofilm Agents Against Oral Pathogens

## TL;DR

Marine-derived Bacillus strains show strong antibacterial and antibiofilm activity against oral pathogens, offering a potential solution to antimicrobial resistance.

## Contribution

Marine-derived Bacillus strains TVD12 and TVW12 demonstrate novel dual antibacterial and antibiofilm capabilities against oral pathogens.

## Key findings

- Bacillus strain TVD12 showed strong inhibition of S. mutans, S. anginosus, S. aureus, and E. faecalis.
- Bacillus strain TVW12 exhibited high antibiofilm activity against E. faecalis, S. aureus, and S. mutans.
- The strains displayed a dual-activity profile with broad-spectrum antimicrobial and pathogen-specific antibiofilm inhibition.

## Abstract

The growing antimicrobial resistance (AMR) is threatening traditional treatments for oral diseases like dental caries and periodontitis, which constitute a significant global health burden. The study aimed to isolate Bacillus species from marine samples, to assess their biosurfactant-producing capabilities, and to evaluate their antibacterial activity against oral pathogens. Bacillus strains were isolated from marine water and sediment samples, identified by phenotypic and genotypic methods, and screened for their biosurfactant-producing ability by drop collapse, hemolytic activity, bacterial adhesion to hydrocarbons (BATH), oil displacement, and emulsification assays. Ethyl acetate extracts of these Bacillus strains were tested for antibacterial efficacy against four oral pathogens (MTCC strains) by the agar-well diffusion method. Among 81 bacterial isolates, 13 were confirmed as Bacillus species by phenotypic and 16S rRNA gene sequencing. Six Bacillus isolates displayed significant antibacterial activity, and the majority were beta-hemolytic. Bacillus strain TVD12 (50 mg/mL) exhibited superior performance by inhibiting S. mutans (31 mm ± 0), S. anginosus (30.5 mm ± 0.7), S. aureus (20 mm ± 1.4), and E. faecalis (29 mm ± 4.24). Bacillus strain TVW12 (500 μg/mL) performs better in antibiofilm activity by inhibiting E. faecalis 90%, S. aureus 87.4%, and S. mutans 76.8%. Statistical analysis revealed a distinct dual-activity profile, characterized by consistent broad-spectrum antimicrobial efficacy (p = 0.809) alongside specialized, pathogen-specific antibiofilm inhibition (p = 0.004). Marine-derived Bacillus strains, such as TVW12, and TVD12 demonstrated effective antibacterial and antibiofilm properties, offering a feasible approach to combat oral pathogens, contributing to sustainable development goals (SDGs) by addressing the challenges of antimicrobial resistance (SDG 3) through sustainable marine bioprospecting (SDG 14). These findings suggest their possibility in developing novel antibacterial agents against oral pathogens in future therapeutic applications.