Enzyme screen finds peptide beats enzymes against tooth biofilm

A screen of seven enzymes against biofilms of Streptococcus mutans, the bacterium most strongly associated with tooth decay, found that only one of them, Dispersin B, showed antibiofilm activity under the tested conditions. Dispersin B showed antibiofilm activity at 0.25 milligrams per milliliter, and only by inhibiting the formation of new biofilm, not by dispersing biofilms that had already formed. In a head-to-head comparison, the short peptide GI6 showed better efficacy at a lower concentration than Dispersin B.

The study, published in Applied Microbiology and Biotechnology, set out to test whether enzymes capable of degrading the structural components of bacterial biofilms could match or beat the antibiofilm performance of GI6, an amyloid hexapeptide developed previously by the same research group. The enzyme panel included mutanase, dextranase, collagenase I, dispase II, cellulase, lysozyme, and Dispersin B, an enzyme that cleaves poly-N-acetylglucosamine, which immunofluorescence staining confirmed to be present in S. mutans biofilms.

Each agent was evaluated against S. mutans for three distinct activities: preventing biofilm from forming in the first place, killing the bacteria directly, and eradicating biofilms that had already matured. Under the conditions tested, six of the seven enzymes failed across the board. Only Dispersin B at 0.25 milligrams per milliliter showed antibiofilm activity. Like GI6, however, Dispersin B lacked bactericidal activity and could not disperse established biofilms.

To confirm that Dispersin B was acting on a real target, the researchers used immunofluorescence staining to check whether its substrate, poly-N-acetylglucosamine, was actually present in S. mutans biofilms. The staining confirmed that it was, indicating that the enzyme had a genuine molecular target in these biofilms even though its practical effect was limited. Scanning and transmission electron microscopy confirmed reduced extracellular polysaccharides and non-bactericidal effects for both DspB and GI6.

In this system, a human enamel block caries model was established to characterize the anti-biofilm and anti-caries effects of the treatments. The effects were characterized using transmission electron microscopy, confocal laser scanning microscopy, scanning electron microscopy, and micro-computed tomography.

The decisive difference between the two agents was dose. GI6 suppressed biofilm formation and enamel demineralization at lower concentrations than Dispersin B, giving the peptide better efficacy under the tested conditions. The authors conclude that most of the enzymes they tested are simply ineffective against S. mutans biofilms, and that even the one enzyme that worked, Dispersin B, requires higher concentrations than GI6 to achieve comparable results.

The failure of both active agents to disperse mature biofilms points to a broader challenge in caries prevention. The authors suggest that future efforts in caries prevention may benefit from agents that more efficiently target the extracellular polysaccharides within mature biofilms, rather than relying on inhibitors of biofilm formation alone.

GI6 is an amyloid hexapeptide developed previously by the same research group. The authors suggest that future efforts in caries prevention may benefit from more effective biofilm-disrupting agents.

Subject of Research: Comparison of seven enzymes and an amyloid hexapeptide for inhibiting and dispersing Streptococcus mutans biofilms and preventing enamel demineralization

Article Title: Comparison of enzymes and amyloid hexapeptide for antibiofilm activity

Article References: Yan, Y., Huang, Y., Yang, S., Lin, H., & Chen, D. (2026). Comparison of enzymes and amyloid hexapeptide for antibiofilm activity. Applied Microbiology and Biotechnology. https://doi.org/10.1007/s00253-026-14084-6

Image Credits: AI Generated

DOI: 10.1007/s00253-026-14084-6

Keywords: Streptococcus mutans, biofilm, Dispersin B, amyloid hexapeptide GI6, dental caries, extracellular polysaccharides, enamel demineralization, poly-N-acetylglucosamine, antibiofilm enzymes, caries prevention, Comparison, enzymes