Lignocellulolytic and hemicellulolytic system of Pycnoporus cinnabarinus: isolation and characterization of a cellobiose dehydrogenase and a new xylanase

Mixed Enzyme Systems for Delignification of Lignocellulosic Biomass

“…First, the enzymes often possess different pH optima, with xylanases and laccases generally showing maximum activity from pH of 4-6.5 and 2-5, respectively. However, as noted by Sigoillot et al in their study of P. cinnabarinus grown on substrates such as sugar beet pulp and maize for the production of an enzyme cocktail for bleached pulp production, the temperature and pH profiles of xylanase and laccase were found to be very similar, with an optimal pH of about 5.0 and a thermal stability of up to 55 °C [31]. Ultimately, the extent of enzyme compatibility may depend on both the enzyme source and the substrate [171].…”

“…For example, bagasse and sawdust were both effective substrates for production of xylanase and phenol oxidase by the thermophilic fungus T. aurantiacus [142]; the activities were measured at day 10 of culture growth. Similarly, maize bran, wheat bran, and sugar beet pulp could each induce the simultaneous production of both laccase and xylanase by P. cinnabarinus, measured at days 6-12 [31].…”

“…Given that phenolic lignin structures account for 10-20% of the lignin substructures in the plant cell wall, laccase was therefore not expected to play a role as a delignifying agent [30,31]. In 1989, however, the combination of laccase and syringaldehyde was shown to oxidize the nonphenolic lignin model compound veratryl alcohol [32].…”

“…Xylanases are widely used in the pulp and paper industry since they increase lignin extractability from kraft pulp by depolymerizing the hemicellulosic material closely associated with lignin in the plant cell wall [31,89]; this includes hydrolysis of precipitated xylan or hydrolysis of the xylan component of LCC in fibers. Consequently, a key reason for the improvement in the bleach response of pulps treated with xylanase is an increase in fiber permeability [87].…”

Investigation of factors affecting xylanase activity from Trichoderma harzianum 1073 D3

“…In studies carried out with Trichoderma sp., it was also concluded that the most suitable pH value for xylanase activity was 5 (Dekker, 1983;Gomes et al, 1992;Royer and Nakkas, 1991). The optimum pH was also around 5 in similar experiments on fungal xylanases (Milagres et al, 1993;Gandhi et al, 1994;Sigoillot et al, 2002). In some other studies, in order to determine xylanase activity generally pH was kept around 5 (Bailey et al, 1992).…”