Biodegradation studies and evaluation of the metabolic potential of cocoa phytopathogenic fungi

Author(s)

Allan Calmont de Andrade Almeida

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2021-04-29

Examining board members

Taicia Pacheco Fill; Anita Jocelyne Marsaioli; Jonas Gruber

• Advisor: Taicia Pacheco Fill

Abstract

The huge increase in the consumption of plastic materials in recent decades has led to ecological and economic concerns that require research related to the discovery of effective methods for the degradation of polymers generated as waste in our daily lives. In this context, biodegradation using microorganisms has been identified as a very promising alternative in the literature. The work, with a strong sustainable approach, contributes towards the generation of a new polymeric material using recycled polyolefins as a matrix and as a load the residues from the cocoa industry in Brazil. The polymeric material already obtained in the laboratory, in partnership with the company Afinko, presented interesting properties, such as increased rigidity and mechanical resistance, in addition to a characteristic chocolate odor. In preliminary studies carried out in our group, the great potential for biodegradation of the new polymeric compound developed with cocoa fibers was verified, through the use of phytopathogenic fungi isolated from the fruit itself. In this sense, this work aims to study the possible metabolites produced from the microbial biodegradation of the polymeric composite with cocoa fibers. Still in this context, studies of all stages of biodegradation were conducted, using seven phytopathogenic fungi that were selected based on the potential for biodegradation reported in the literature. In view of the above, our work had as main objective to study the chemical and biochemical mechanisms involved in biodegradation with a focus on the secondary metabolism of fungi, biodegradation agents, during the process. The fungi Colletotrichum gloeosporioides and Fusarium graminearum are the fungi that stood out in terms of composite degradation and secondary metabolism. The fungus C. gloeosporioides stood out in mechanical terms, generating a decrease of 9.0% in the yield stress of the plastic, after 75 days incubated with the polymer, indicating a partial degradation, confirmed through the SEM where the presence of the phytopathogen inside the polymer. Analyzes indicated that under biodegradation conditions, the fungus produces hydroxyacorenone, which has anti-glycation properties. The fungus F. gramineraum reduced the rupture deformation by 44.6%, and its presence in the fungus inside the plastic was verified through SEM analysis, confirming the potential for degradation. Biodegradation studies have intensified the production of mycotoxin zearalenone by the fungus, which could contribute to studies with this mycotoxin. Therefore, this work was able to sustainably close the life cycle of the new material (AU)

• FAPESP's process: 18/20930-6 - Biodegradation and metabolic studies of phytopathogenic fungi from cocoa
• Grantee: Allan Calmont de Andrade Almeida
• Support Opportunities: Scholarships in Brazil - Master