Purpose Spent mushroom compost (SMC) is a major solid waste product of the mushroom industry and is the material which remains at the end of a mushroom crop. Methods Different proportions of the SMC from Agaricus subrufescens cultivation were tested to produce seedlings and plants of tomato. A commercial substrate was used, both as a control and in combination with the spent compost in different proportions. So two experiments were carried out, the first was the production and evaluation of tomato seedlings and the second was tomato cultivation from seedlings produced in the first experiment. Results The use of different proportions of spent A. subrufescens compost resulted in a decreasing trend of all the parameters in the production of the tomato seedlings. However, in tomato cultivation for all periods of harvest, a positive effect was observed in fruiting when the seedlings were produced with spent A. subrufescens compost in comparison to the commercial control. Conclusion It was concluded that the use of spent A. subrufescens compost for seedling production led to a higher total tomato production compared to previously reported production levels in organic cultivation systems with green, organic and other types of fertilization. These results demonstrated the great potential of spent A. subrufescens compost for use in organic tomato production because of the better quality of harvested fruit.

The successful production of marketable lettuce heads with full exploitation of the genetic potential of a particular cultivar depends on the availability of seedlings of the highest quality. The aims of the present study were (i) to evaluate the effects of substrates containing different proportions of spent mushroom compost on the growth of lettuce seedlings, and (ii) to determine the enduring effects of substrates containing spent mushroom substrate on the vigor of mature lettuce plants derived from such seedlings. The substrates employed in the germination and development of lettuce seedlings were obtained by mixing spent compost from the cultivation of Agaricus subrufescens and commercial vegetable substrate in different proportions. Seedlings were evaluated with respect to the number of leaves and the height, fresh mass and dry mass of the aerial parts, while mature plants were appraised according to stem height and circumference, fresh mass and dry mass of the lettuce head. Substrate containing between 42 to 48% spent mushroom substrate provided the most adequate conditions for the growth and development of crisphead lettuce seedlings and, consequently, of vigorous marketable plants. Under such conditions, the fresh mass of the aerial parts of seedlings attained a level of 0.89 g plant -1 , while the fresh mass of the marketable heads achieved a maximum of 233.45 g plant -1 . The data presented herein verify that top quality lettuce seedlings yield high quality marketable heads, and that quality improvement can be brought about by the addition of spent mushroom substrate.

The production of compost is one of the most important steps for the cultivation of any species of mushroom. For the Agaricus species, this step is even more complex because it depends on the performance of different microorganisms that act on the substrate, turning it into selective compost that promotes the growth of the fungus to be cultivated. Among the various factors that affect the microbial activity, the initial concentration of nitrogen is considered one of the most important. Due to the lack of conclusive studies about that, the aim of this study was to evaluate the productivity and biological efficiency of Agaricus brasiliensis in compost prepared with different initial concentrations of nitrogen, according to the composting methodology and to the conventional pasteurization techniques (phase I and II). Three initial nitrogen concentrations (w/w) (T1= 1.0%; T2= 1.5%; and T3= 2.0%) were tested and mycelial growth was determined in terms of mm/day for all treatments. The productivity and biological efficiency were also determined. The most efficient initial concentrations of nitrogen were of 1.0% and 1.5%. This concentration of N in the compost permitted a faster development of the mushroom with higher productivity when compared to the results obtained with the application of 2% of nitrogen.

Commercial productivity of the Agaricus blazei mushroom is closely related to both the quality of the compost and the choice of soil to be used as a casing material. This study aims to evaluate Agaricus blazei's productivity using two compost formulations and three soils. The two compost formulations were (i) crushed sugarcane bagasse (Saccharum officinarum (L.)) and Coastcross hay (Cynidon dactylon (L.) Pers.), and (ii) crushed sugarcane bagasse (Saccharum officinarum (L.)) and corn husk (Zea mays L.); they were amended with wheat bran, lime, gypsum, superphosphate and urea. The casing materials were extracted from three soils classed as Rhodic Hapludox, Xanthic Hapludox, and Humic Haplaquox. The Rhodic Hapludox soil material was mixed with fragments of Eucalyptus charcoal in the proportion of 4:1. The compost was prepared during six weeks and thereafter heat treated during 48 h at the end of the composting period. The sugarcane bagasse:coast-hay compost was superior to the sugarcane bagasse: corn husk compost. The Rhodic Hapludox plus charcoal casing material showed to be a better casing material than either the Xanthic Hapludox and Humic Haplaquox soil materials. The choice of the soils where the casing material is taken is an important factor to the success of the Agaricus blazei mushroom cultivation.

Banana stalks and Bahia grass were utilized as basic starting materials for the production of the mushroom Pleurotus sajor-caju. Banana stalks were combined with other waste or supplement products (wheat bran, coast-cross hay, bean straw and cotton textile mill) to obtain different nitrogen concentrations. Since Bahia grass is relatively rich in protein, it was combined with other substrates (banana stalk, coast-cross hay and bean straw) to maintain a substrate nitrogen concentration of about 1.5%. Banana stalks and Bahia grass were both more efficient in the production of the mushroom P. sajor-caju when utilized without the addition of other substrates, with biological efficiencies of 74.4% and 74.12%, respectively. When combined with other substrates or grasses, there was a drop in biological efficiency, independent of the concentration of nitrogen. Furthermore, the addition of protein-rich waste to banana stalks resulted in a decrease or absence of fructification, which indicates that high concentrations of nitrogen in the cultivation substrate may hinder the cultivation of this mushroom. On the other hand, results reveal that the ideal concentration of nitrogen may depend on other physicochemical factors and these factors may determine the success in cultivating P. sajor-caju. Therefore, we conclude that P. sajor-caju may be cultivated on banana stalk and Bahia grass as pure substrates, not being necessary their supplementation or combine them with another substrates.

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.

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The aim of this research was to evaluate the application of different microbial additives during composting, on some parameters of the production of Agaricus subrufescens. Compost was prepared over two weeks with ammonia assimilating bacterial and a thermophillic fungus as microbiological additives. These additives were introduced during two week composting to promote greater selectivity of the substrate cultivation and provide increased productivity of mushrooms. The data shows that the microbiological additives used in composting had a significantly higher productivity, when compared to treatments without additives. These species can be used as microbiological additives in A. subrufescens cultivation.