Banca de DEFESA: DAYANE RODRIGUES DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DAYANE RODRIGUES DA SILVA
DATE: 28/08/2025
TIME: 14:30
LOCAL: Google Meet
TITLE:

ANALYSIS OF THE BIOREMEDIATION POTENTIAL OF IMIDACLOPRID BY PHOTOSYNTHESIZING MICROORGANISMS AND THEIR EFFECTS ON PIGMENT PRODUCTION

KEY WORDS:

Microalgae; Pesticides; Bioactives; Ficoremediation.

PAGES: 68
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUBÁREA: Bioquímica dos Microorganismos
SUMMARY:

The mango crop in the São Francisco Valley suffers losses due to pest attacks, leading to the extensive use of pesticides such as Imidacloprid, which has high solubility and stability in water, contributing to its environmental persistence. Additionally, it is toxic to non-target organisms, highlighting the need for its removal from aquatic environments. Microalgae, due to their metabolic and physiological capabilities, emerge as promising tools for pesticide bioremediation. This study aimed to evaluate the potential of Tetradesmus obliquus, Arthrospira platensis, and Dunaliella tertiolecta in the bioremediation of Imidacloprid, as well as the pigment content in microalgal biomass. The microalgae were cultivated in Erlenmeyer flasks containing standard culture medium, with an initial insecticide concentration of 0.2 mg/L and a microorganism concentration of 100 mg/L. The experiments were conducted under two conditions: (1) culture medium and microorganisms; and (2) culture medium, microorganisms, and Imidacloprid, to assess the effect of the pesticide on microalgal growth. Cell concentration was determined daily throughout the cultures. The analysis of maximum cell concentration (Xm) indicated that Imidacloprid stimulated growth in all microalgae. T. obliquus exhibited the highest Xm (837.97 mg/L in the treated group and 733.55 mg/L in the control), followed by D. tertiolecta (811.55 mg/L treated and 682.48 mg/L control) and A. platensis (577.80 mg/L treated and 472.26 mg/L control). The maximum specific growth rate (μMAX) demonstrated that the pesticide did not interfere with the doubling rate of D. tertiolecta (0.17 day⁻¹), while T. obliquus and A. platensis showed reductions from 0.15 to 0.13 day⁻¹ and from 0.12 to 0.10 day⁻¹ in the treated and control groups, respectively. Regarding productivity, D. tertiolecta showed the most significant increase (58.86 mg L⁻¹ day⁻¹ in the treated group compared to 52.59 mg L⁻¹ day⁻¹ in the control), which may be attributed to its greater ability to utilize Imidacloprid as a carbon source. T. obliquus maintained similar productivity between groups (48.77 mg L⁻¹ day⁻¹ treated and 48.67 mg L⁻¹ day⁻¹ control), while A. platensis showed no significant difference (29.23 mg L⁻¹ day⁻¹ treated versus 30.60 mg L⁻¹ day⁻¹ control). The results highlight the potential of T. obliquus and D. tertiolecta in Imidacloprid bioremediation, with metabolic adaptations that enhance growth and productivity. In contrast, A. platensis demonstrated greater sensitivity. Thus, T. obliquus and D. tertiolecta emerge as promising candidates for bioremediation applications. Future studies should explore metabolic degradation pathways, resulting products, and the interference of the pesticide in the photosynthetic apparatus.

COMMITTEE MEMBERS:
Presidente - RAQUEL PEDROSA BEZERRA
Interna - MARIA TACIANA HOLANDA CAVALCANTI
Externa à Instituição - ALEXSANDRA FRAZÃO DE ANDRADE
Externa à Instituição - ANNA GABRIELLY DUARTE NEVES