The effects of aeration and veratryl alcohol on the production of two laccases by the ascomycete Botryosphaeria sp.

The ascomycete, Botryosphaeria sp, produced two extracellular constitutive laccases (PPO-I and PPO-II) active toward the substrates: 2, 21-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) [ABTS], and 2,6-dimethoxyphenol (DMP), respectively. The production of both laccases increased when the fungal isolate was grown in the presence of veratryl alcohol, and resulted in optimal laccase production (100- and 25- fold, respectively) at 40 mM. The effect of aeration on growth and laccase production was studied in baffled flasks, and showed that aeration of the cultures increased the production of both enzymes 4–5 fold in the presence of veratryl alcohol. Both laccases were susceptible to inhibition by azide, acetate and chloride anions. Veratryl alcohol inhibited the laccase-catalyzed polymerization of DMP. Growing cultures of Botryosphaeria sp. produced an exopolysaccharide of the β-glucan type whose synthesis was depressed when grown in the presence of veratryl alcohol.