Growth and photosynthesis of Helianthus annuus L. under fertilization with biomass of microalgae cultivated in sanitary sewage

• Grant number: 22/11514-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2022
• Effective date (End): August 31, 2023
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Gustavo Henrique Ribeiro da Silva
• Grantee: Elisa Teófilo Ferreira
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

Seeking to adapt to the demands of a constantly growing population, it is necessary to change the productive model employed, moving from an inefficient linear model to a circular economy model aimed at closing product cycles. Due to the great energy demand for obtaining chemical fertilizers, the instability in obtaining them due to conflicts in Eastern Europe, and their negative environmental impact, the search for new sources for crop fertilization is of great importance for agriculture. From a circular economy perspective, sanitary sewage is a source of nutrient and energy recovery, therefore, the recovery of these nutrients and their destination for the fertilization of agricultural crops can increase the cost-effectiveness of wastewater treatment and fertilization, at the same time that favors the development of sustainable agriculture. The cultivation of microalgae will occur in a flat panel photobioreactor, with sanitary sewage pre-treated in an anaerobic upflow anaerobic sludge blanket (UASB) reactor as a culture medium, with the addition of activated sludge to aid in flocculation. The application of microalgae will be made in the cultivation of Helianthus annuus L., one of the most important plants for oil production today, having cultivars that present between 47 and 51% of oils in their composition, in addition to their various applications for food and production of medicines. The cultivation will take place in a greenhouse, under natural photoperiodic conditions, and the application of microalgae biomass will be carried out together with the planting of the seeds and every 20 days. Thus, the objective of this project will be to analyze the effectiveness of the use of native microalgae, cultivated in pre-treated sewage as an organic fertilizer to replace chemical fertilization in the culture of the C3 plant, H. annuus L. Specifically, the effects of the use of microalgae on growth, gas exchange, photosynthetic pigment synthesis, shoot biomass production and leaf mineral content will be analyzed.