Strategies for improving ligninolytic enzyme activities in semi-solid-state bioreactors

Abstract

The production of ligninolytic enzymes by Phanerochaete chrysosporium BKM-F-1767 (ATCC 24725) was studied in laboratory-scale bioreactors, operating under semi-solid-state conditions. The bioreactors were filled with inert support (polypropylene sponges) and cultivation was carried out in batch. Veratryl alcohol (2 mM) and Tween 80 (0.05% v/v) were added at the beginning of the fermentation to stimulate the production of ligninolytic enzymes. A modification in the design of a bioreactor, which operates in semi-solid-state conditions, lead to a significant improvement in the ligninolytic enzyme activities obtained. Thus, by modifying the design of the bioreactor employed in the current study, it was possible to increase about tenfold manganese-dependent peroxidase (MnP) activities and around 40% lignin peroxidase (LiP) activities. Moreover, both MnP and LiP profiles were more regular in the modified bioreactor.