Substrato de cultivo para os cogumelos Pleurotus ostreatus e Agaricus bisporus: composição físico-química e metagenômica microbiana
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Data
2016-05-20
Autores
Vieira, Fabrício Rocha [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Entre os cogumelos cultivados comercialmente, destacam-se o Agaricus bisporus e Pleurotus ostreatus (cogumelo ostra). A preparação do substrato de cultivo é a etapa mais crítica da produção, determinante para a produtividade e custos de produção. O método de preparo do substrato mais utilizado pela indústria de cogumelos é a compostagem curta, seguida de pasteurização e condicionamento. Como ponto chave da compostagem, a comunidade microbiana tem papel fundamental no processo, conferindo seletividade final do substrato de cultivo e, consequentemente, a produtividade. Desta forma, avaliou-se, o manejo da compostagem (tempo de compostagem e temperatura de pasteurização) e o efeito sob a comunidade microbiana, composição final do substrato e produtividade de cogumelos. Para isto, foram realizados três experimentos. Nos experimentos 1 e 2, avaliou-se a influência do tempo de compostagem (fases I e II), a comunidade microbiana (bactérias e fungos), variáveis físico-químicas, produtividade, número de cachos e precocidade do cogumelo P. ostreatus. Os resultados obtidos mostraram que o manejo da compostagem influenciou a comunidade microbiana e, consequentemente, a seletividade final do substrato de cultivo, com reflexos na produtividade e número de cachos. A comunidade microbiana apresentou menor diversidade na compostagem com menor duração e, menor perda de carbono, nitrogênio e açúcares solúveis, resultando em substrato mais seletivo ao cogumelo P. ostreatus, demostrando melhores resultados de produtividade. No experimento 3, avaliaram-se, a comunidade microbiana e indicadores químicos do composto final, em diferentes situações de pasteurização durante a preparação do substrato para o cultivo do cogumelo A. bisporus. Para isto, foram simuladas em biorreatores três diferentes situações de pasteurização (57°C por 6 horas, 60°C por 2 horas e 68°C por 2 horas). O sequenciamento da comunidade microbiana revelou a predominância dos filos Proteobacteria e Firmicutes durante as fases I e II de compostagem, respectivamente. Os gêneros bacterianos mais abundantes foram Pseudomonas e Thermobifida, durante a fase I, e Ureibacillus, Luteimonas, Truepera, Pseudoxathomonas, Clostridium e Paenebacillus, durante a fase II. A comunidade fúngica foi composta predominantemente por indivíduos do filo Ascomycota, com maior abundância dos gêneros Thermomyces e Scedosporium, durante a fase I, e Thermomyces e Mycothermus, durante a fase II. O composto submetido à pasteurização a 60°C por 2 horas apresentou maior redução no teor de matéria orgânica, sólidos totais e relação C/N. Por outro lado, o composto pasteurizado a 68°C apresentou menor teor de nitrogênio, consequência da maior emissão de NH3 durante a fase II. Por último, a modernização dos cultivos de cogumelos requer continuidade das pesquisas envolvendo a ecologia microbiana da compostagem, com foco no papel funcional destes microrganismos, auxiliando na tomada de decisão sobre o manejo da compostagem.
Among many commercial mushrooms cultivated, Agaricus bisporus and Pleurotus ostreatus (oyster mushroom) are the most important for mushroom industry. The cultivation substrate preparation is the most critical step in mushroom production, determining productivity and production costs. The substrate preparation method most used by mushroom industry is short composting, followed by pasteurization and conditioning. As key point of composting, microbial community plays an important role during the process, determining final substrate selectivity and mushroom yield. Thus, aimed evaluate the influence of composting management (composting time and pasteurization temperature) in microbial community, final substrate composition and mushroom yield. For this, were conducted three experiments. In experiments 1 and 2 were evaluated the influence of composting time (phases I and II), microbial community (bacteria and fungi), physicochemical variables and P. ostreatus yield. The results showed that composting management (time of phases I and II) influenced the microbial community, substrate selectivity and consequently mushroom yield and number of cluster. The microbial community showed less diversity in composting with shorter duration, as well as the losses of carbon, nitrogen and soluble sugars, showing higher selectivity of substrate for P. ostreatus, as observed in yield results. In experiment 3, were evaluated the microbial community (bacteria and fungi) and some physiochemical variables in different pasteurization conditions during substrate preparation for A. bisporus cultivation. Were simulated in bioreactors three different pasteurization conditions (57°C for 6 hours, 60°C for 2 hours and 68°C for 2 hours). The sequencing of microbial community revealed the predominance of phyla Proteobacteria and Firmicutes during phase I and II composting, respectively. The most abundant bacterial genera were Pseudomonas and Thermobifida during phase I and Ureibacillus, Luteimonas, Truepera, Pseudoxanthomonas, Clostridium and Paenebacillus during phase II. Fungal community was predominantly composed by Ascomycota phylum, with higher abundance of Thermomyces and Scedosporium genera during phase I and Thermomyces and Mycothermus during phase II. The compost pasteurized at 60°C for 2 hours showed the highest reduction in organic matter content, total solids, and C/N ratio. Moreover, the compost pasteurized at 68°C showed lower nitrogen content, a consequence of higher emission of NH3 during phase II. At last, modernization of mushroom cultivation system requires further study involving microbial ecology and focus on functional role of these microorganisms during the composting process, assisting in decision-making on composting management.
Among many commercial mushrooms cultivated, Agaricus bisporus and Pleurotus ostreatus (oyster mushroom) are the most important for mushroom industry. The cultivation substrate preparation is the most critical step in mushroom production, determining productivity and production costs. The substrate preparation method most used by mushroom industry is short composting, followed by pasteurization and conditioning. As key point of composting, microbial community plays an important role during the process, determining final substrate selectivity and mushroom yield. Thus, aimed evaluate the influence of composting management (composting time and pasteurization temperature) in microbial community, final substrate composition and mushroom yield. For this, were conducted three experiments. In experiments 1 and 2 were evaluated the influence of composting time (phases I and II), microbial community (bacteria and fungi), physicochemical variables and P. ostreatus yield. The results showed that composting management (time of phases I and II) influenced the microbial community, substrate selectivity and consequently mushroom yield and number of cluster. The microbial community showed less diversity in composting with shorter duration, as well as the losses of carbon, nitrogen and soluble sugars, showing higher selectivity of substrate for P. ostreatus, as observed in yield results. In experiment 3, were evaluated the microbial community (bacteria and fungi) and some physiochemical variables in different pasteurization conditions during substrate preparation for A. bisporus cultivation. Were simulated in bioreactors three different pasteurization conditions (57°C for 6 hours, 60°C for 2 hours and 68°C for 2 hours). The sequencing of microbial community revealed the predominance of phyla Proteobacteria and Firmicutes during phase I and II composting, respectively. The most abundant bacterial genera were Pseudomonas and Thermobifida during phase I and Ureibacillus, Luteimonas, Truepera, Pseudoxanthomonas, Clostridium and Paenebacillus during phase II. Fungal community was predominantly composed by Ascomycota phylum, with higher abundance of Thermomyces and Scedosporium genera during phase I and Thermomyces and Mycothermus during phase II. The compost pasteurized at 60°C for 2 hours showed the highest reduction in organic matter content, total solids, and C/N ratio. Moreover, the compost pasteurized at 68°C showed lower nitrogen content, a consequence of higher emission of NH3 during phase II. At last, modernization of mushroom cultivation system requires further study involving microbial ecology and focus on functional role of these microorganisms during the composting process, assisting in decision-making on composting management.
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Palavras-chave
Pleurotus ostreatus, Agaricus bisporus, Compostagem, Composição físico-química, Metagenômica, Composting, Physicochemical composition, Metagenomics