Method for the stabilization and immobilization of enzymatic extracts and its application to the decolorization of textile dyes.

Peroxidases from Pleurotus eryngii have been investigated for their ability to degrade recalcitrant, phenolic pollutants. The use of crude enzymatic extracts can reduce the high costs associated with enzyme purification, and enzyme immobilization can enhance enzyme stability and recovery. The present study tests the effectiveness of various conditions for crude enzyme stabilization in polyethylene glycol and glycine solutions, and immobilization on monofunctional and heterofunctional agarose solid supports. Glycine at 0.5 M at 4 °C and pH 4 was most effective stabilization agent for the crude enzymatic extracts, and enzyme immobilization efficiency was greatest for heterofunctional supports. MANA-glyoxyl heterofunctional supports were demonstrated to have the greatest enhancement of decolorization (1.3-fold) and velocity of substrate consumption (fivefold). Therefore, the application of crude enzymatic extracts to industrial processes, such as dye decolorization, represents a cost-effective alternative to purified enzymes.

Toward an understanding of the effects of agitation and aeration on growth and laccases production by Pleurotus ostreatus.

Mycelial growth and laccase production by Pleurotus ostreatus CP50 cultured in a 10-L mechanically agitated bioreactor were assessed through a 2(3) factorial experimental design. The main effects and interactions of three factors (agitation, aeration and copper induction) over five responses (µ, αLacc, ßLacc, maximal volumetric laccase activity and maximal biomass concentration) were analyzed. P. ostreatus growth was significantly improved when culturing was conducted with high agitation (5.9kW/m(3)s) and aeration flow (0.5vvm) rates. Under the experimental conditions evaluated, no evidence of hydrodynamic stress affecting fungal growth was observed. However, the high agitation and aeration conditions were detrimental for the growth-associated laccase production constant (αLacc), leading to a very complex optimization of the process. The maximal laccase volumetric activity (1.2 and 3.8U/ml for non-induced and copper-induced cultures, respectively) was observed when the culturing was performed at a low agitation rate (0.9kW/m(3)s) and a high aeration flow rate (0.5vvm). Laccase proteolysis may explain the complex interactions observed between agitation and aeration and the effects of these factors on the laccase volumetric activity observed in the cultures.

Lignocellulolytic enzyme production of Pleurotus ostreatus growth in agroindustrial wastes

The mushroom Pleurotus ostreatus has nutritional and medicinal characteristics that depend on the growth substrate. In nature, this fungus grows on dead wood, but it can be artificially cultivated on agricultural wastes (coffee husks, eucalyptus sawdust, corncobs and sugar cane bagasse). The degradation of agricultural wastes involves some enzyme complexes made up of oxidative (laccase, manganese peroxidase and lignin peroxidase) and hydrolytic enzymes (cellulases, xylanases and tanases). Understanding how these enzymes work will help to improve the productivity of mushroom cultures and decrease the potential pollution that can be caused by inadequate discharge of the agroindustrial residues. The objective of this work was to assess the activity of the lignocellulolytic enzymes produced by two P. ostreatus strains (PLO 2 and PLO 6). These strains were used to inoculate samples of coffee husks, eucalyptus sawdust or eucalyptus bark add with or without 20 % rice bran. Every five days after substrate inoculation, the enzyme activity and soluble protein concentration were evaluated. The maximum activity of oxidative enzymes was observed at day 10 after inoculation, and the activity of the hydrolytic enzymes increased during the entire period of the experiment. The results show that substrate composition and colonization time influenced the activity of the lignocellulolytic enzymes.(AU)

Pleurotus opuntiae (Durieu et Lév.) Sacc. (higher Basidiomycetes) and other species related to Agave and Opuntia plants in Mexico-taxonomy, distribution, and applications.

Pleurotus opuntiae is an important mushroom from xerophytic temperate regions of Mexico, as parasite or saprobe on Agave and Opuntia. Discussions on the taxonomic relationships of P opuntiae with P djamor, P. agaves, P. levis, and P. yuccae are presented, of which P. agaves is a synonym of P. opuntiae, and P. yuccae is a synonym of P. djamor. This latter and P levis are close species of P. opuntiae. The traditional uses of P opuntiae and P. djamor as food and remedy for several health problems, and also to get a traditional alcoholic drink from the Agave, are also considered.

Entomofauna associada ao cultivo de Pleurotus sajor-caju (Fr) Singer (Agaricales: Agaricaceae) no município do Capão do Leão, RS, Brasil / Insects associated with the Pleurotus sajor-caju (Fr) Singer (Agaricales: Agaricaceae) crop in the county of Capão do Leão, RS, Brazil

O objetivo deste trabalho foi conhecer a diversidade de artrópodes associada ao cultivo de Pleurotus sajor-caju em palha de arroz pasteurizada em ambiente semicontrolado, localizado no sul do Rio Grande do Sul. A captura dos espécimes foi realizada no período de abril a maio de 2007, durante a fase de frutificação da cultura, compreendendo 45 dias. Foram realizadas nove coletas com intervalos de 5 dias, utilizando armadilhas INTRAL AL 012 (12 volts). Capturou-se um total de 3.129 indivíduos divididos em cinco ordens com predominância de Diptera (2.874), Hymenoptera (152), Ortoptera (69), Colembola (59) e Coleoptera (38). A ordem Diptera foi a que apresentou o maior número de famílias, sendo Mycetophilidae (2.530), Sciaridae (264), Cecidomyiidae (10), Phoridae (46), Muscidae (4), Calliphoridae (1) e Culicidae (19).

The objective of this research was to know the diversity of arthropods associated to the Pleurotus sajor-caju crop in rice straw pasteurized in a semicontrolled environment, located in the south of the state of Rio Grande do Sul, Brazil. The capture of specimens was carried out in the period of April through May 2007, during the phase of fruit bodies of the crop, lasting 45 days. Nine collections with intervals of 5 days were carried out, using INTRAL AL 012 (12 volt) traps. A total of 3129 individuals divided into five orders with predominance of Diptera (2874), Hymenoptera (152), Ortoptera (69), Colembola (59) and Coleoptera (38) was captured. The Diptera order was the one that presented the biggest number of families, being Mycetophilidae (2530), Sciaridae (264), Cecidomyiidae (10), Phoridae (46), Muscidae (4), Calliphoridae (1) and Culicidae (19).

Determination of biological species and analysis of genetic variability by RAPD of isolates of Pleurotus subgenus Coremiopleurotus.

Isolates of Pleurotus cystidiosus and P. smithii were studied to verifie the occurrence of P. cystidiosus instead of P. smithii in South America. The two species are mainly separated by the growth rate of the anamorph in culture, the morphology of the anamorph and teleomorph, intercompatibility tests, and genetic variability. In order to see if the isolate found in Brazil and previously identified as Antromycopsis macrocarpa (the anamorph of P. cystidiosus) belongs to P. cystidiosus, a species with a world wide distribution, or to P. smithii which is restricted to Mexico and South America, or if P. cyistidiosus and P. smithii are the same species, isolates of different geographic origins were studied. Growth rate in culture, mono-dikaryotic matings, and genetic variability determined by RADP were investigated. The results show that the criteria used to separate the two species are unsatisfactory, and that P. smithii should be considered a synonym of P. cystidiosus; this extends the distribution of this later species to Central and South America.

Biomass and exopolysaccharide production in submerged cultures of Pleurotus ostreatoroseus Sing. and Pleurotus ostreatus "florida" (Jack.: Fr.) Kummer.

The species of the genus Pleurotus produce large amounts of biomass and exopolysaccharide (EPS) in submerged cultures, which may be used for biotechnological purposes. In the present work two Brazilian autochthonous strains of edible Pleurotus (P. ostratoroseus Sing. and P. ostreatus "florida") were used. The fungi grown in liquid Potato Dextrose medium (PD) were used as inocula to cultivate those microorganisms in the POL culture medium. After a 9-day incubation, the optimal growth time for biomass production, P. ostreatus "florida" presented higher biomass production (22.8 g d.w./l) than P. ostreatoroseus (16.8 g d.w./l). After a 7-day incubation, the optimal growth time for EPS production, P. ostreatoroseus produced higher amounts of crude EPS (5.8 g d.w./l) than P. ostreatus "florida" (1.4 g d.w./l). Relative carbohydrate composition for P. ostreatoroseus and P. ostreatus "florida" EPS were: glucose (95.5-87.7), galactose (traces - 4.9), mannose (traces - 3.1), xylose (1.3-2.5), and arabinose (3.2-1.8). Lower ammonium sulfate concentration in the POL culture medium increased the exopolysaccharides production by P. ostreatoroseus.