Production, characterisation and evaluation of Coprinus peroxidase for phenolic wastewater treatment

In this study, non-ligninolytic extracellular fungal peroxidases from Coprinus species were investigated as cost-effective alternatives to plant peroxidase for their application to phenolic wastewater treatment.; Based on a series of screening experiments, C. cinereus UAMH 4103 and Coprinus sp. UAMH 10067 and the peroxidases produced by these fungi were selected for further investigation. Batch productions of extracellular peroxidase by these fungi were successfully optimised through a series of growth experiments.; The extracellular peroxidases produced by these two Coprinus species were purified and characterised. Purified Coprinus peroxidases have a molecular weight of around 36 kDa based on MALDI-TOF mass spectrometry. The amino acid composition analyses of two Coprinus peroxidase revealed that they had very similar amino acid compositions, and that they were also similar to the previously studied C. cinereus peroxidase from different sources and also to Arthromyces ramosus peroxidase.; Although the catalytic properties of two Coprinus peroxidases were also very similar to each other, the thermal and pH stabilities of these enzymes were substantially different. The peroxidase from Coprinus sp. UAMH 10067 was more stable than that from C. cinereus UAMH 4103 at an elevated temperature and under weakly acidic and weakly basic conditions. Both enzymes performed equally well in aqueous phenol removal around neutral pH; however, the peroxidase from Coprinus sp. UAMH 10067 worked better at pH 9 than did that from C. cinereus UAMH 4103.; When crude Coprinus peroxidases were used, the enzyme requirements to achieve 95% removal of 1.1 mM phenol from buffered solutions were 15 to 18 times smaller than those when purified ones were used. The crude Coprinus peroxidases showed similar phenol removal efficiencies to those of previously studied plant and fungal peroxidases. Treatment of real wastewater from an oil refinery with a crude Coprinus peroxidase was also successfully demonstrated in this study. These results indicate that crude Coprinus peroxidases, particularly that from Coprinus sp. UAMH 10067, have a potential for their large-scale production and application to phenolic wastewater treatment.