Viabilidade da produção e aplicação de biocompostos a partir do fungo trichoderma koningiopsis por processo fermentativo submerso em biorreator

Abstract

The growing demand for food is responsible for stimulating the agricultural sector. However, large volumes of nutrients are lost in production, a fact related to the action of weeds present in these environments. For the control of these weeds, chemical compounds are usually used, and their excessive application, besides being able to stimulate resistance in the invasive plant, affects the environmental quality and human health. Due to this, we are looking for new technologies of weed management, demanding researches from biological herbicides (bioherbicides), which have their production based on plants and phytopathogenic microorganisms, mainly fungi. In this sense, the objective of this work was to evaluate the viability of the production and application of biocomposites from the fungus Trichoderma koningiopsis by fermentative process submerged in bioreactor. For this, fermentative tests were carried in a bioreactor, and samples were taken every 24 hours to evaluate the enzymatic production (amylase, cellulase, lipase and peroxidase) and then at end of fermentation the fungal biomass was quantified. T. koningiopsis sensitivity tests in the presence of synthetic herbicides (Dichlorophenoxyacetic acid (2,4-D), Glyphosate and Ammonium Glufosinate) were carried out with the purpose of evaluating the effect of combination and possible synergism of these two agents against the control of weeds. First, inhibitory halo formation was evaluated in Petri dishes, evaluating the sensitivity or fungal resistance against the synthetic herbicides tested. This combination was also tested in a fermentation process for subsequent application to the following weeds: Bidens pilosa, Conyza bonariensis and Euphorbia heterophylla. In an overall view of the study, the results obtained in fermentation process in scale expansion showed that in 72 hours the highest enzymatic production occurred, reaching up to 80% of phytoxicity in the weeds. The microorganism T. koningiopsis showed resistance to most of the chemical herbicides tested, including high dosages of Glyphosate, suggesting that fungus shows ability to adapt the medium containing extreme doses of synthetic herbicides. In the application of biocomposites in the presence of synthetic herbicides, suggests potentiation of the phytotoxic action (100%) under the target plants, emphasizing phytotoxicity to the “buva” (Conyza bonariensi), currently resistant to available synthetic herbicides. The bioherbicides studied have promising characteristics to be explored in the biocontrol of weeds, addressing aspects in the ambit of environmental sustainability.