Avaliação de métodos de fermentação e formulação de bacillus velezensis para uso como bioprotetor na agricultura
Data
2022-07-21
Autores
Dure, Laís Mayara Melo
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Bacillus é um dos gêneros de bactérias com diversidade biotecnológica reconhecidos por secretarem vários metabólitos que promovem o crescimento das plantas e previnem a infecção por patógenos. O presente trabalho teve como objetivo otimizar a produção de endósporos do isolado de Bacillus velezenses AP-3 via fermentação líquida e fermentação semi-sólida; produzir uma formulação de fungicida biológico à base de endósporo, bem como avaliar o potencial como agente de controle de Sclerotinia sclerotiorum e Fusarium oxysporum f. sp. lycopersici e como promotor de crescimento em plantas de feijão. Os ensaios foram conduzidos no Laboratório de Microbiologia Ambiental “Raquel Ghini” e em Casa de Vegetação da Embrapa Meio Ambiente, Jaguariúna, SP. Nos ensaios conduzidos em laboratório foram otimizadas combinações entre variáveis que interferem no processo fermentativo, tanto em meio semi-sólido, como líquido. A partir de suspensões destes meios foi estudado o potencial antagonista do isolado por meio da produção de antibióticos e metabólitos contra S. sclerotiorum e F. oxysporum f. sp. lycopercisi. Também foram obtidas formulações em pó utilizando talco e fécula de batata. O ensaio de promoção de crescimento de plantas consistiu em avaliar os formulados em diferentes formas de aplicação (tratamento de semente, aplicação no sulco de semeadura e tratamento de sementes em associação com aplicação em sulco de semeadura). As modificações de variáveis no meio de cultura alteraram a quantidade de endósporos produzidos por B. velezensis AP-3. A produção via fermentação em estado sólido com farinha de arroz e fécula de batata foi viável quando fermentadas por 7 dias em meio com 60% de umidade, sendo as maiores medias de concentrações de 2,06 x 108 e 1,82 x 108 UFC g-1. Por outro lado, o meio de Melaço + Farelo de Algodão produziu 1,69 x 109 UFC mL-1 de endósporos de B. velezensis via fermentação submersa. As formulações obtidas a partir dos endósporos produzidos via fermentação submersa em mistura com talco e fécula de batata apresentaram viabilidade estável em formulações por até 226 dias (última avaliação). O isolado inibiu o crescimento micelial dos dois patógenos testados, além disso, apresentou potencial para promoção de crescimento de plantas de feijão influenciando positivamente o desenvolvimento do sistema radicular.
Bacillus is one of the bacteria genera with biotechnological diversity recognized for secreting several metabolites that promote plant growth and prevent infection by pathogens. The objectives of this study were to optimize endospore production of Bacillus velezensis strain AP-3 via liquid fermentation and semi-solid fermentation; to produce an endospore-based biofungicide formulation, as well as to evaluate its potential as a control of Sclerotinia sclerotiorum and Fusarium oxysporum f. sp. lycopersici, and as a growth promoter in bean plants. The assays were carried out at the Laboratory of Environmental Microbiology “Raquel Ghini” and at the greenhouse of Embrapa Meio Ambiente, Jaguariúna, SP. In the assays carried out in the laboratory combinations between variables that interfere in the fermentation process were optimized, both in solid and liquid media. From suspensions of these media, the antagonistic potential of the isolate was studied through the production of metabolites against S. sclerotiorum and F. oxysporum f. sp. lycopercisi. Powder formulations were obtained in talc and potato starch. The plant growth promotion assays consisted of evaluating the formulas in several delivery application (seed treatment, application in the sowing furrow and seed treatment associated with application in the sowing furrow). The variables evaluated in the culture medium changed the concentration of endospores produced by B. velezensis AP-3. Solid-state fermentation in medium containing rice flour and potato starch was viable when fermented for 7 days in a medium with 60% humidity, with the highest mean concentrations of 2.06 x 108 and 1.82 x 108 UFC g -1 . On the other hand, the Molasses + Cotton Bran medium produced 1.69 x 109 CFU mL-1 of B. velezensis via submerged fermentation. The formulations obtained from the endospores produced via submerged fermentation in a mixture with talc and potato starch showed stable viability in formulations for up to 226 days (last evaluation). The isolate inhibited the mycelial growth of the two pathogens evaluated, in addition, it showed potential for promoting the growth of bean plants, positively influencing the development of the root system
Bacillus is one of the bacteria genera with biotechnological diversity recognized for secreting several metabolites that promote plant growth and prevent infection by pathogens. The objectives of this study were to optimize endospore production of Bacillus velezensis strain AP-3 via liquid fermentation and semi-solid fermentation; to produce an endospore-based biofungicide formulation, as well as to evaluate its potential as a control of Sclerotinia sclerotiorum and Fusarium oxysporum f. sp. lycopersici, and as a growth promoter in bean plants. The assays were carried out at the Laboratory of Environmental Microbiology “Raquel Ghini” and at the greenhouse of Embrapa Meio Ambiente, Jaguariúna, SP. In the assays carried out in the laboratory combinations between variables that interfere in the fermentation process were optimized, both in solid and liquid media. From suspensions of these media, the antagonistic potential of the isolate was studied through the production of metabolites against S. sclerotiorum and F. oxysporum f. sp. lycopercisi. Powder formulations were obtained in talc and potato starch. The plant growth promotion assays consisted of evaluating the formulas in several delivery application (seed treatment, application in the sowing furrow and seed treatment associated with application in the sowing furrow). The variables evaluated in the culture medium changed the concentration of endospores produced by B. velezensis AP-3. Solid-state fermentation in medium containing rice flour and potato starch was viable when fermented for 7 days in a medium with 60% humidity, with the highest mean concentrations of 2.06 x 108 and 1.82 x 108 UFC g -1 . On the other hand, the Molasses + Cotton Bran medium produced 1.69 x 109 CFU mL-1 of B. velezensis via submerged fermentation. The formulations obtained from the endospores produced via submerged fermentation in a mixture with talc and potato starch showed stable viability in formulations for up to 226 days (last evaluation). The isolate inhibited the mycelial growth of the two pathogens evaluated, in addition, it showed potential for promoting the growth of bean plants, positively influencing the development of the root system
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Palavras-chave
Bacillus spp, Controle biológico, Formulação de bioprodutos, Processos fermentativos., Biological control, Formulation of bioproducts, Fermentation processes