Cultivation of Pleurotus mushrooms in substrates obtained by short composting and steam pasteurization

This paper presents results of two experiments for cultivation of Pleurotus ostreatus, Pleurotus pulmonarius and Pleurotus eryngii grown with different formulations of grass and straw mixtures derived from agro-industrial residues. Cultivation was prepared through a number of approaches, such as short composting/pasteurization and axenic culture. In the first experiment, P. pulmonarius was grown on two formulations of different grasses, with no significant differences observed for either productivity or biological efficiency, with values close to 20 and 60%, respectively. The second experiment revealed similar productivity and biological efficiency between P. pulmonarius and P. ostreatus for both forms of substrate treatment (short composting/pasteurization vs. axenic culture), with similar values to those observed in the first experiment. P. eryngii did not produce mushrooms in the composting treatment and showed lower productivity (17.5%) than the other two species (20.5 and 20.8%, respectively) when the substrates were autoclaved (axenic culture). The preparation for short composting and steam pasteurization was described in illustrative figures in order to provide expertise to small producers who wish to initiate economic and sustainable mushroom cultivation making use of regional lignocellulosic residues.Keywords: Steam pasteurization, lignocellulosic biomass, straw mixtures, mushroom

Sebacinales Everywhere: Previously Overlooked Ubiquitous Fungal Endophytes

Inconspicuous basidiomycetes from the order Sebacinales are known to be involved in a puzzling variety of mutualistic plant-fungal symbioses (mycorrhizae), which presumably involve transport of mineral nutrients. Recently a few members of this fungal order not fitting this definition and commonly referred to as ‘endophytes’ have raised considerable interest by their ability to enhance plant growth and to increase resistance of their host plants against abiotic stress factors and fungal pathogens. Using DNA-based detection and electron microscopy, we show that Sebacinales are not only extremely versatile in their mycorrhizal associations, but are also almost universally present as symptomless endophytes. They occurred in field specimens of bryophytes, pteridophytes and all families of herbaceous angiosperms we investigated, including liverworts, wheat, maize, and the non-mycorrhizal model plant Arabidopsis thaliana. They were present in all habitats we studied on four continents. We even detected these fungi in herbarium specimens originating from pioneering field trips to North Africa in the 1830s/40s. No geographical or host patterns were detected. Our data suggest that the multitude of mycorrhizal interactions in Sebacinales may have arisen from an ancestral endophytic habit by specialization. Considering their proven beneficial influence on plant growth and their ubiquity, endophytic Sebacinales may be a previously unrecognized universal hidden force in plant ecosystems

Purification and characterization of a thermostable alkaline cellulase produced by Bacillus licheniformis 380 isolated from compost

<div><p>ABSTRACT During composting processes, the degradation of organic waste is accomplished and driven by a succession of microbial populations exhibiting a broad range of functional competencies. A total of 183 bacteria, isolated from a composting process, were evaluated for cellulase activity at different temperatures (37, 50, 60, and 70°C) and pH values. Out of the 22 isolates that showed activity, isolate 380 showed the highest cellulase activity. Its ability to produce cellulase was evaluated in culture medium supplemented with carboxymethyl cellulose, microcrystalline cellulose, wheat straw, and rice husk. The culture medium supplemented with carboxymethyl cellulose induced higher enzyme activity after 6 hours of incubation (0.12 UEA mL-1 min-1). For wheat straw and rice husk, the results were 0.08 UEA mL-1 min-1 for both, while for microcrystalline cellulose, 0.04 UEA mL-1 min-1 were observed. The highest carboxymethyl cellulase activity was observed at 60°C (0.14 UEA mL-1 min-1) for both crude and partially purified enzyme after 30 and 120 min of incubation, respectively. Alkalinization of the medium was observed during cultivation in all substrates. The cellulase had a molecular mass of 20 kDa determined by SDS-Page. Isolate 380 was identified as Bacillus licheniformis. This work provides a basis for further studies on composting optimization.</p></div