Isolation, screening and identification of catalaseproducing fungi using a rapid agar plug assay and biosorption potential of Penicillium commune

Vaishali M. Songire, Darshana R. Gawale, Amruta A. Joshi & Ravindra H. Patil

Sydowia 79: 199-211

Published online on August 26th, 2026

Catalase (EC 1.11.1.6) is a key antioxidant enzyme that enables fungi to withstand oxidative stress by decomposing hydrogen peroxide (H2O2), a reactive oxygen species commonly encountered in natural and disturbed habitats. In the present study, thirty fungal isolates were obtained from different environmental sites including hot springs, industrial effluents, sewage soil and leaf litter. The isolates were screened for catalase production using hydrogen peroxide-amended medium and potassium permanganate (KMnO4) discoloration. Ten isolates exhibited catalase activity, among which isolates C1 and C2 showed the highest activity. Quantitative spectrophotometric analysis confirmed catalase activities of 52.36 kU/L and 52.35 kU/L for C1 and C2, respectively. Morphological, biochemical and 18S rRNA gene sequencing identified C1 as Penicillium commune and C2 as Candida neerlandica. Both isolates showed optimal growth at acidic pH values of 4.5 and 3.5 respectively and temperatures of 25–30 °C, exhibited starch hydrolysis, and lacked urease activity and germ tube formation. The biosorption potential of Penicillium commune was evaluated for removal of Congo red. A decrease in absorbance over 7 days indicated effective dye removal, with maximum decolourization of 60.6 % observed at 0.75 g biomass. Higher biomass did not significantly enhance removal, likely due to aggregation effects. The findings highlight the ecological significance of catalase as a protective mechanism in fungi inhabiting oxidative environments and demonstrate the functional diversity of catalase-producing taxa in sewage-associated ecosystems.The study also demonstrates an adapted rapid screening approach for enzyme-based fungal selection and shows that Penicillium commune is a potential biosorbent for sustainable wastewater treatment.

Keywords: catalase, agar plug assay, fungal isolates, biosorption, environmental samples, enzyme screening.

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