Use of fungal enzymes to study the degradation of specific plant polyphenols

A fraction of procyanidin (PC) was purified from the cider apple and used as the sole carbon source in order to evaluate the potency of different filamentous fungi to grow and degrade them. Fiftegn filamentous fungi were screened in a mineral medium with or without glucose. Almost all the strains were observed to have PC degradation ability. Aspergillus fumigatus was the most efficient fungus that degraded >5OVo of PC after 72h of growth. This strain was selected for further studies. The PC cultured samples were analyzed by thiolysis-HPlC method and constitutive units (catechin units) ofPC polymer were quantified and characterized. Kinetics ofPC degradation revealed that the terminal units of PC decreased during fermentation and on the contrary, an increase in the average degree of polymerization (DPn) from 8 to 36 was also observed at the end of fermentation. These findings suggested that terminal units were possibly modifred by the enzymatic action of the fungus. Normal-Phase HPLC analysis showed that PC oligomers were degraded during the early phase