Metabolism of cellulose by Phanerochaete chrysosporium in continuously agitated culture is associated with enhanced production of lignin peroxidase

Production of the extracellular heme protein lignin peroxidase (LiP) by Pha nerochaete chrysosporium is currently associated with a number of requireme nts, namely exposure of the cultures to oxygen; limiting nutrient nitrogen or carbon and static or semi-static culture conditions. To obtain LiP activ ity in continuously agitated liquid culture requires the inclusion of a sur factant. However, using cellulose as the carbon source, we obtained high ti tres (0.2-0.4 U ml(-1)) of LiP in submerged liquid cultures under condition s of continuous agitation, without substrate limitation or the need to add oxygen or surfactant. Comparison of the morphological and physiological tra its of hyphae maintained on either cellulose or free glucose supports obser vations that the synthesis of extracellular polysaccharide in the cultures grown on glucose, restricts oxygen diffusion into the hyphae, which is nece ssary for LiP induction. They also suggest that isozymes of LiP synthesised under these conditions may be triggered in response to oxidant stress. (C) 2000 Elsevier Science B.V. All rights reserved.