Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made.
a b s t r a c tWheat straw was submitted to a pre-treatment by the basidiomycetous fungi Euc-1 and Irpex lacteus, aiming to improve the accessibility of cellulose towards enzymatic hydrolysis via previous selective bio-delignification. This allowed the increase of substrate saccharification nearly four and three times while applying the basidiomycetes Euc-1 and I. lacteus, respectively. The cellulose/lignin ratio increased from 2.7 in the untreated wheat straw to 5.9 and 4.6 after the bio-treatment by the basidiomycetes Euc-1 and I. lacteus, respectively, thus evidencing the highly selective lignin biodegradation. The enzymatic profile of both fungi upon bio-treatment of wheat straw have been assessed including laccase, manganese-dependent peroxidase, lignin peroxidase, carboxymethylcellulase, xylanase, avicelase and feruloyl esterase activities. The difference in efficiency and selectivity of delignification within the two fungi treatments was interpreted in terms of specific lignolytic enzyme profiles and moderate xylanase and cellulolytic activities.
This work looks for a better understanding of the biodegradation of xenobiotic azo dyes mediated by yeasts. During a screening program of phenolic acid assimilating capacities it was found that a non-conventional ascomycetous yeast isolate, identified as Candida oleophila, efficiently decolorizes agar plates supplemented with the commercial textile diazo dye Reactive Black 5. Aerobic batch cultures of C. oleophila could completely decolorize up to 200 mg dye l −1 , an ability not yet reported for this yeast species. Moreover, this performance has been achieved in just 24 h of incubation at 26 • C in the presence of as little as 5 g glucose l −1 and without visible signs of dye adsorption to yeast cells. It was found that decolorization occurs during the exponential growth phase and neither laccase nor manganese-dependent peroxidase activities were detected in the culture medium. As far as the decolorization mechanism is concerned, our results indirectly suggest the involvement of an azoreductase-like activity in azo bonds cleavage.
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