Polymeric microparticles as a carrier system of the fungus Trichoderma harzianum for agricultural applications.

Author(s)

Cintia Rodrigues Maruyama

• Document type: Doctoral Thesis
• Press: Sorocaba. 2019-09-04.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Ciência e Tecnologia. Sorocaba
• Defense date: 2019-08-26
• Advisor: Leonardo Fernandes Fraceto

Abstract

Demand for the use of products for sustainable agriculture with less impact on the environment has been increasing. Thus, the use of biological control is an alternative to reduce the use of pesticides and the consequent risks. The fungus Trichoderma harzianum is an example of effective biological control against the pathogen Sclerotinia sclerotiorum (white mold), which affects many crops and yields losses of up to 100%. However, the use of this biological control fungus may encounter some problems such as fungal stress due to biotic and abiotic factors. One possible solution to this type of problem is microencaking. Thus, this work aimed to develop calcium alginate and chitosan microparticles as a fungal carrier system, to characterize the microparticle system through physicochemical methods, molecular evaluation of soil microbiota, antagonism against S. sclerotiorum phytopathogen and the effect of microparticles on plants. The average size of the calcium alginate and chitosan microparticles was 2000 μm and 2500 μm, respectively. Scanning electron microscopy confirmed the spherical morphology of the microparticles after the dehydration process. The photostability assay revealed greater protection of the fungus Trichoderma harzianum when encapsulated in calcium alginate microparticles. Differential Scanning Calorimetry (DSC) and Infrared Spectroscopy (FTIR) assays showed the interaction of microparticles with the fungus T. harzianum. Molecular evaluation of soil microbite showed an increase in the proportion of denitrifying bacteria during exposure. The encapsulation of the fungus in calcium alginate microparticles increased the control efficacy against the phytopathogen. The T. harzianum encapsulation showed improvement in chitinolytic and cellulosic activity. Chitosan microparticles were not effective for encapsulating this fungus. The effects of microparticles containing encapsulated fungus on plants showed no phytotoxicity and microparticles promoted higher growth on these plants. Thus, the encapsulation of the fungus T. harzianum was possible in calcium alginate microparticles and has potential use for agriculture. (AU)

• FAPESP's process: 15/18231-4 - Polymeric microparticles as the fungus Trichoderma harzianum carrier system aimed at applications in agriculture
• Grantee: Cintia Rodrigues Maruyama
• Support Opportunities: Scholarships in Brazil - Doctorate