Resumen: Este trabajo evaluó la tasa de crecimiento micelial (Kr) y la producción de basidiomas de dos cepas comerciales del hongo shiitakeLentinula edodes(B05 y M3790) en formulaciones compuestas de residuos lignocelulósicos procedentes de actividades agrícolas y agroindustriales de la región andina de Patagonia Norte y de materiales leñosos de plantas invasoras. Las formulaciones consistieron de un sustrato base, como chips de madera de sauce (ChS), chips de madera de rosa mosqueta (ChRM), pelusa de rosa mosqueta (PRM) o virutas de lenga (VL), mezclado con un suplemento, como salvado de trigo (ST) o bagazo de cebada cervecera (BC). Las dos cepas evaluadas mostraron mayores Kr con ChRM-ST. La producción de basidiomas tuvo lugar lo largo de 1 a 4 oleadas, durante un máximo de 124 días. Las máximas eficiencias biológicas (EB) se obtuvieron con la cepa M3790, destacándose ChS (118,86%) y VL (88,73%), ambos suplementados con ST. La cepa B05 alcanzó las máximas EB con ChS-ST (54,72%) y con ChRM-BC (50,43%). Los resultados obtenidos especialmente con ChRM y ChS, sumado a su abundancia en Patagonia argentina, sugieren que estos materiales pueden ser aprovechados como sustratos para la producción comercial de shiitake, actividad aún no desarrollada a gran escala en la región.

Summary: This work assessed the mycelial growth rate (Kr) and basidiome production of two commercial strains of shiitake mushroomLentinula edodes(B05 and M3790) in formulations composed of lignocellulosic residues from agricultural and agroindustrial activities in Northern Andean Patagonia and woody materials from invasive plants. The formulations consisted of a base substrate, such as willow wood chips (ChS), rosehip wood chips (ChRM), rosehip fluff (PRM) or southern beech shavings (VL), mixed with a supplement, such as wheat bran (ST) or malting barley bagasse (BC). Both strains showed the highest Kr with ChRM-ST. Basidiome production took place over 1 to 4 flushes for a maximum of 124 days. The highest biological efficiencies (EB) were obtained with strain M3790, particularly using ChS (118.86%) and VL (88.73%), both supplemented with ST. Strain B05 showed the highest EB in ChS-ST (54.72%) and in ChRM-BC (50.43%). The results obtained, especially in ChRM and ChS, in addition to their abundance in Argentinian Patagonia, suggest that these materials can be used as substrates for the commercial production of shiitake, an activity that is still not developed on a large scale in this region.

Abstract The effects of a naturally occurring Patagonian strain of the white-rot fungus Pleurotus ostreatus on Araucaria araucana wood lignans was evaluated. Lignans of colonized and non-colonized wood shavings and the activity of fungal ligninolytic enzymes were studied. Lignans were identified using gas chromatography with a mass spectrometry detector. Only eudesmin lignan resisted biological degradation. The highest laccase activity was 0.111 ± 0.067 IU.g-1 dry matter substrate, which was reached after 60 days, whereas the highest manganese peroxidase (MnP) activity was 0.220 ± 0.109 IU.g-1 dry matter substrate, which was reached after 25 days, when the fungus was grown in a solid-state culture on wood shavings. The degradation properties of this fungal strain may be useful for not only treating resinous wastes from the regional forest industry to produce biofuels but also improving paper production. Moreover, the capacity of this white-rot fungus to grow on resinous A. araucana materials as substrate suggests the possibility of using the wood shavings or sawdust of this and other conifers as a food source to culture P. ostreatus, an edible mushroom.

Resumen Se evaluaron los efectos de una cepa patagónica de Pleurotus ostreatus sobre la composición de los lignanos de madera de Araucaria araucana. Se estudiaron los lignanos presentes en virutas de madera colonizada y no colonizada por el hongo y se evaluaron las actividades de las enzimas ligninolíticas. Los lignanos se identificaron mediante cromatografía de gases acoplada a espectrómetro de masas (GCMS). Solamente el lignano eudesmin resistió la degradación biológica. La mayor actividad de la enzima lacasa detectada fue de 0,111 ± 0,067 UI.g-1, que se alcanzó luego de 60 días, mientras que la mayor actividad de la enzima manganeso peroxidasa (MnP) fue de 0,220 ± 0,109 UI.g-1 a los 25 días de cultivo. Las propiedades degradativas de esta cepa fúngica pueden ser útiles, no solamente para tratar los desechos resinosos de la industria forestal regional sino también para producir biocombustibles a partir de estos, o aplicarlos en la producción de papel. Además, la capacidad de este hongo de podredumbre blanca para crecer en un sustrato resinoso como A. araucana sugiere la posibilidad de usar las virutas o aserrínes de coníferas como sustrato para cultivar un alimento de valor como P. ostreatus.

Abstract: Mycelium composites consist of particulate lignocellulosic materials, e.g., sawdust from the timber industry structured as a solid matrix resulting from the mycelial growth. Many protocols have been proposed based on different strains and substrates. However, the influence of intrinsic elements, such as the structure of the hyphal system on the main parameters required by the industry still needs to be researched. The main goal of this work is to assess the performance of five Patagonian lignocellulolytic fungal species for producing mycelium composites. Strains of these species were studied in order to assess the relation between basidiome hyphal structure and the hyphal structure of mycelium-based materials. Comparisons of the hardness in the Janka scale were performed with commercial expanded polystyrene. Composites resulting from the growth of Pleurotus ostreatus, Nothophellinus andinopatagonicus and Funalia trogii successfully formed composites, showing a lower quality than Ganoderma austral. Ryvardenia cretacea in turn completely failed to colonize the substrate. The material resulting from the growth of Ganoderma australe on pine sawdust (a substrate chosen based on its local availability) is proposed as a good substitute with improved resistance.

Abstract: The basidiomes production of two strains of Pleurotus ostreatus (one native from Patagonia, Argentina, isolated from the conifer Araucaria araucana and the other one a commercial strain) grown in different agricultural and forestry wastes was studied. The ability of the native strain generates interest to know its degradative capabilities for its use with conifer waste from the regional forest industry, which is dominated by the use of exotic Pinus species. In addition, white poplar (Populus alba), southern beech (Nothofagus pumilio), wheatgrass (Thinopyrum ponticum) and residues from beer brewing were also explored as substrates. The native strain showed better productivity of basidiomes with a biological efficiency of 17,86 % ± 3,74 % on pine wood shavings in comparison with the commercial strain used as control. The best substrates were poplar and wheatgrass with biological efficiency between 35,28 % to 88,5 % and 27,84 % to 84,01 %, respectively. Supplemented substrates showed better productivity than those without supplement. The low biological efficiency on pine could be attributed to the aromatic compounds contents because, in growth test, the diameter of the fungal colony was affected negatively by the addition of pine resin volatiles, mainly with α-limonene and δ-3-carene. In spite of the low biological efficiency, promising inter-breeding or hybrids generation could improve yields in future assays.

Abstract Background: Pleurotus spp. are fungi characterized by their ability to biologically degrade lignocellulosic materials. In Argentina, 6 wild Pleurotus species are known, being P. pulmonarius and P. ostreatus the ones with the greatest bio technological interest. Objective: To determine the phylogenetic relationships of Pleurotus strains from Patagonia and their enzymatic capacity (laccase) at low temperatures. Methods: A phylogenetic analysis of the ITS regions of 8 wild Pleurotus strains from Patagonia and Parana region in north east and central Argentina was carried out. Laccase activity of the strains was quantified using dimethoxyphenol (DMP) as substrate, incubating at 30 and 10 ºC, with and without previous heat treatment at 80 ºC. Results and conclusions: Phylogenetic analysis of the ITS region of Pleurotus strains showed that Patagonian strains belong to P. ostreatus (5) and non-Patagonian strains to P. pulmonarius (3). Laccase activity was no relationship between the retention capacity and the origin of the strains, with more than 50 % retention of activity at 10 ºC, therefore it viable their use in biotechnological processes that require low temperature conditions.

Resumen Antecedentes: Pleurotus spp. son hongos reconocidos por su capacidad de degradar biológicamente materiales lignocelulósicos. En Argentina se conocen 6 especies de Pleurotus nativas, siendo P. pulmonarius y P. ostreatus las de mayor interés biotecnológico. Objetivo: Determinar las relaciones filogenéticas de cepas de Pleurotus de la Patagonia y su capacidad enzimática (lacasa) a bajas temperaturas. Métodos: Se realizó un análisis filogenético de las regiones ITS de 8 cepas de Pleurotus de Patagonia y la región de Paraná en el noreste y centro de la Argentina. Para cuantificar la actividad lacasa se usó dimetoxifenol (DMP) como sustrato, incubando a 30 y 10 ºC, con y sin tratamiento previo de calor a 80 ºC. Resultados y conclusiones: El análisis filogenético determinó que las cepas provenientes de la Patagonia (5) correspondían a P. ostreatus, y las no patagónicas a P. pulmonarius (3). Con respecto a la actividad de lacasa, no se observó una relación entre la capacidad de retención y el origen de las cepas, registrándose más del 50 % de retención de la actividad a 10 ºC, por lo que su uso en procesos biotecnológicos que requieren condiciones de bajas temperaturas es potencialmente viable.