Tea extract as an inexpensive inducer of pectin lyase in Penicillium griseoroseum cultured on sucrose

Extracts of tea, coffee, cocoa, and yeast induced pectin lyase (PL) in Penicillium griseoroseum cultured in a mineral medium with sucrose as the carbon source. PL activity and fungal growth were similar in the treatments with 0.5% tea extract, the highest concentration tested, and 0.03% yeast extract. When tea extract was added singly to the culture medium, P. griseoroseum produced 59% and 17% of the PL activity and mycelial mass, respectively, obtained in a treatment with tea extract and sucrose. These results suggest that the production of the enzyme was not proportional to mycelial growth. No PL was produced in the medium with sucrose and without inducers. The small amounts of pectic substances present in the tea extract could not be responsible for PL induction. PL activity was detected after 12 h of growth in the medium containing sucrose and tea extract added at time zero, and after 48 h of growth when tea extract was added at times 12 and 24 h. Mycelial mass in all treatments was similar after 48 h of incubation. However, the addition of tea extract at time zero increased PL activity by 20–25%. Cyclic AMP at 5 and 10 mM in the culture medium induced 20 and 30%, respectively, of the PL activity obtained with 0.03% yeast extract, suggesting that PL induction brought about by either yeast extract or tea extract might involve the intracellular metabolism of cAMP. Received 22 October 1996/ Accepted in revised form 09 January 1997