Produção de conídios e enzimas hidrolíticas por Beauveria Bassiana (Bals) vuillemin (Deuteromycotina: Hyphomycetes) em diferentes substratos

• Ano de defesa: 2016
• Autor(a) principal: Guimarães, Ana Gabriella Lucena de Paiva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Biotecnologia; Programa de Pós-Graduação em Biotecnologia; UFPB
• Palavras-chave em Português: Controle biológico; Substratos naturais; Fungos filamentosos; Enzimas extracelulares; Fermentação; Natural substrates; Filamentous fungi; Extracellular enzymes; Biological control, fermentation; CIENCIAS BIOLOGICAS
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/tede/8839

Beauveria bassiana is an entomopathogenic fungus used in the biological control of insect pests in agriculture. The production costs of its conidia, on a large scale, in the standard substrate (rice) currently used, affects the production process. Finding alternatives as a way of minimizing process costs has led to the need to investigate the efficiency of alternative substrates that, in addition to important nutritional properties, have high availability and low cost. Entomopathogenic fungi produce enzymes that are involved in the process of pathogenicity and virulence. However, when stimulated by specific substrates they can produce enzymes of biotechnological interest. Thus, the objective of this work was to analyze the potential of different substrates (algaroba fiber, malt residues, acerola seeds and fibers, and sugarcane bagasse) for conidiogenesis and enzymatic production (solid state fermentation) from of B. bassiana. The experiments for the production and viability of the conidia were carried out in triplicate, in erlernmeyer (250 mL) containing 30 g of each substrate, 0.3 μL of the conidial suspension (1 x 106 conidia/mL), humidity of 70 ± 10 % and Temperature (T = 29 ± 1 ° C). After 10 days of incubation, the rice substrates (standard medium) (2.00 × 106 conidia/g substrate), malt A (1.22 × 106 conidia/g), malt B (1.75 × 106 conidia/g), and algaroba fiber (2.36 x 106 conidia/g) provided higher conidia production. The viability of the conidia produced in these same substrates did not differ statistically among them, with a germination percentage of 99.96; 90.04; 93.17 and 98.21 %, respectively. The pathogenicity of the B. bassiana conidia produced on the different substrates was evaluated in the coconut termite. The mortality rate of infected termites did not differ statistically, surpassing 80 % mortality, except for the control group. The enzymatic activity (cellulolytic and amylolytic) was determined by the DNS method (dinitrosalicylic acid). The substrates used in the solid state fermentation, malt A (1.178 ± 0.002 U/mL), malt B (2.392 ± 0.013 U/mL), algaroba fiber (0.596 ± 0.007 U/mL) and acerola seed (0.964 ± 0.09 U/mL) showed amylolytic activity. From this analysis, different temperatures (30°, 40º, 50º, 60º, 65º, and 70º C) were evaluated to identify the optimum temperature of the amylolytic enzymes produced in this process. It was observed that the greatest activities found were in extreme temperatures, in the range of 60º to 70º C, suggesting that these enzymes are thermophilic. Sugarcane bagasse presented higher cellulolytic activity (15.29 ± 0.07 U/mL) for CMcase and (2.58 ± 0.9 U/mL U/mL) for FPase due to the characteristic of its cellulosic matrix, which differs from the other substrates. Proteolytic activity was quantified using azocasein. The algaroba had the highest activity (0.514 ± 0.009 U / mL). The alternative substrates used for growth and sporulation of B. bassiana can provide a reduction of approximately 50 % in the cost of producing conidia of entomopathogenic fungi used in the biological control of several insect pests. In addition, they are presented as a viable alternative for the production of microbial enzymes with wide application in several biotechnological processes.