Production of laccase and manganese peroxidase by Fomes sclerodermeus grown on wheat bran

Abstract

The aim of this work was to study the growth and production of ligninolytic enzymes by Fomes sclerodermeus using a natural medium based on wheat bran as the principal substrate in a solid-state fermentation. Growth was monitored by measuring the chitin content in the substrate. The maximum rate of growth was observed between days 7 and 18. A 38% total dry-weight loss of the substrate was measured after 28 days of cultivation. Differential hydrolysis of the substrate revealed that cellulose was more extensively degraded than lignin. In the 28-day incubation period, the losses of cellulose and lignin were 38 and 15%, respectively. No lignin peroxidase activity was found in any of the media tested. The maximum manganese-dependent peroxidase activity recorded was 6.3 U g⁻¹ at 14 days, while the maximum laccase activity was 270 U g⁻¹ at 28 days post-inoculation. Addition of commonly used inducers such as copper or manganese did not produce a further increase in the enzyme activities, nor did addition of glucose, asparagine, or malt extract.