Decontamination of co-amoxiclav antibiotic from aquatic media by novel isolated yeast Meyerozyma guilliermondii DF3 under optimized condition.

Antibiotic residues, as emerging micropollutants in surface water, threaten human health and ecosystems. The degradation of antibiotics is an essential process for safeguarding public health. This study identifies and optimizes a novel yeast strain for co-amoxiclav (AMC) degradation. Meyerozyma guilliermondii DF3 (Accession No. MZ477354) was isolated from soil using a basal mineral medium (BMM) supplemented with AMC. The strain degraded 75% of AMC within 72 h. Key culture conditions (temperature (20-35 °C), carbon sources (glucose/glycerol), inoculum size (1-5% v/v), and pH (5-9) were optimized via single-factor experiments and Box-Behnken design (BBD). Residual antibiotic levels were quantified by UV spectroscopy and HPLC. Optimal biodegradation occurred with glycerol/glucose, pH 6, and 1% inoculum (1 × 10⁸ cells/mL) at 30 °C. Response surface methodology (RSM) predicted complete degradation (100%) at pH 6.25, 1.02% inoculum, and 95.76 h, with pH being the most influential factor. These findings highlight M. guilliermondii DF3 as a promising candidate for AMC bioremediation in aquatic environments, advancing yeast-based strategies for water treatment.