Production, characterization, and anti-biofilm activity of dextranase from Penicillium citrinum against Streptococcus mutans

Abstract

Streptococcus mutans is widely recognized as a major contributor to dental plaque formation and continues to pose significant oral health challenges across the globe. Its ability to thrive within complex biofilm structures renders it highly resistant to conventional treatment approaches, thereby playing a critical role in the onset and progression of dental caries and periodontal diseases. Despite the availability of various plaque control strategies, many suffer from limitations related to efficacy, safety, and long-term use—emphasizing the urgent need for more effective and sustainable alternatives. This study investigated the biochemical properties and anti-biofilm efficacy of dextranase from Penicillium citrinum, with the goal of evaluating its potential as a promising agent for disrupting biofilms formed by S. mutans. Dextranase was successfully purified using Sephadex G-100 gel filtration chromatography, resulting in a 3.35-fold increase in specific activity and a final enzyme yield of 73.99 %. The enzyme demonstrated optimal catalytic activity at 40 °C in its crude form and at 50 °C after purification. Additionally, it exhibited peak functionality at pH 6 and pH 4 for the crude and purified forms, respectively. Metal ion studies showed that Cu2+, Mg2+, and Fe2+ enhanced enzyme activity, whereas Zn2+, Ca2+, and EDTA had strong inhibitory effects. The purified dextranase completely prevented and eradicated S. mutans biofilm adherence (100 % inhibition), while the crude extract achieved a 44 % reduction. These findings underscore the enzyme's potential as a safe, natural, and effective anti-biofilm agent for use in biopharmaceuticals and oral hygiene solutions aimed at preventing plaque accumulation and related disease