Lignocellulolytic enzyme profiles of edible mushroom fungi

Abstract

One of the most economically-viable processes for the bioconversion of many types of lignocellulosic wastes is represented by edible mushroom cultivation. Lentinula edodes, Volvariella volvacea and Pleurotus sajor-caju are three important commercially cultivated mushrooms which exhibit varying abilities to utilise different lignocellulosics as growth substrate. Examination of the lignocellulolytic enzyme profiles of the three species show this diversity to be reflected in qualitative variations in the major enzymic determinants (i.e. cellulases, ligninases) required for substrate bioconversion. For example, L. edodes, which is cultivated on highly lignified substrates such as wood or sawdust, produces two extracellular enzymes which have been associated with lignin depolymerisation in other fungi, (manganese peroxidase and laccase). Conversely, V. volvacea, which prefers high cellulose-, low lignin-containing substrates produces a family of cellulolytic enzymes including at least five endoglucanases, five cellobiohydrolases and two β-glucosidases, but none of the recognised lignin-degrading enzymes.

Crescimento micelial de dois isolados de <em>Lentinula edodes</em> (Berk.) Pegler, em resíduos ligninocelulósicos

“…Segundo Rajarathnam e Bano (1987), a produção de lacase e consequente degradação da lignina é maior durante a fase de colonização do substrato pelo micélio. O uso de substratos variados na produção de fungos é limitado quando, em sua composição, inibe ou estimula a secreção de celulases, hemicelulases e ligninases para a liberação de nutrientes necessários ao crescimento (Buswell et al, 1996). Desta forma, a suplementação com farelos, compondo os substratos, pode promover sua rápida colonização (Rossi et al, 2001).…”

Wild and domesticated mushroom consumption in Nigeria

“…Agricultural wastes, which otherwise would have been burnt or constitute a nuisance to the ecosystem (Bano et al, 1993;Buswell et al, 1996;Cohen et al, 2002) become useful to produce useful vegetables suitable for all gender classes.…”

Proximate composition and amino acid profile of rice husk biodegraded with Pleurotus ostreatus for different periods

“…However, it has been established that fungi degraded lignin faster than bacteria and also enhanced the protein content of substrate through the addition of fungal protein [9]. Pleurotus ostreatus or oyster mushroom is a fungus which is capable of bio-conversion of varieties of lingo-cellulosic materials due to the secretion of extracellular enzymes [10,11]. Available information on the nutritional changes when native rice husk (NRH) is fermented with fungus at different periods is limited.…”