Characterization of α-amylase and antimicrobial activity of Penicillium chrysogenum

Abstract

Fungi have been used to produce a number of bioactive compounds that include enzymes and antibacterial agents with unique characteristics in vitro. Penicillium chrysogenum is a mould with great potentials for producing important secondary metabolites. This study aimed at characterizing α-amylase and antimicrobial activity of P. chrysogenum. The organism was grown in a solid-state fermentation (SSF) medium using cassava peels as only carbon source. The molecular mass of the amylase was estimated to be 59 kDa by combined results of Amicon Ultra-15 filter unit (Sigma) 50 kDa MWCO and polyacrylamide gel electrophoresis (PAGE). Optimum activity of 93.1 U/mL was noticed at 30oC and pH of 5.8. Stability assay revealed that the enzyme was stable at 40°C and 50°C by retaining 66% and 37% residual activities, respectively. Also, crude extract of P. chrysogenum was found to inhibit Pseudomonas aeruginosa and Staphylococcus aureus with minimum inhibitory concentrations (MIC) of 25 and 12.5 mg/mL respectively. Therefore, these properties make P. chrysogenum an interesting fungus that has the potential of being used to produce both antibacterial agents and α-amylase for the bio-economy.

Keywords

• hydrolytic enzymes
• molecular mass
• fungal species
• bacterial culture
• enzyme assay