Bulletin Spring‧Summer 1995

Straw mushrooms (Volvariella volvacea) growing on cotton waste compost Phoenix tail mushrooms (Pleurotusa j o r - c a j u ) growing on cotton wasteandused tea leaves.The one-sided growth ofthe pileus produces mushrooms that look like phoenix tails. For instance, the researchers have found that the straw mushroom — V o l v a r i e l l a volvacea — would flourish on wastes that contain only small quantities of lignin, because this species is unable to produce any of the lignin-degrading enzymes, and hence unable to draw nutrition from wastes with a large amount of lignin. At the same time, it has been found that this species produces a family of cellulolytic enzymes, some of which possess novel catalytic properties. Another commercially important mushroom, P l e u r o t u s s a j o r - c a j u , can produce abroad spectrum of lignocellulolytic enzymes, and this is reflected in its ability to grow on waste residues of widely varying composition. Various sophisticated techniques including fast-protein liquid chromatography and confocal microscopy have been adopted to pu r i fy indivdual lignocellulolytic enzymes and to investigate how the enzymes are secreted by the mushroom hyphae (the slender filaments which constitute the vegetative growth of the fungus). Genes encoding the production of cellulolytic enzymes in V o l v a r i e l l a vo vacea are now being isolated and cloned to determine the effects of over-production on mushroom growth and fruit body yields. Also, since this mushroom does not appear to produce lignin-degrading enzymes, future research will be directed at inserting into V o l v a r i e l l avolvacea the genes from other fungi encoding the production of enzymes involved in lignin transformation. This is expected to extend the range of lignocellulosic wastes on which the Research 17