Production of bioactive compounds by Chlorella minutissima in a semicontinuous reactor: effects of photoperiod, leachate, CO¿, and feed flow rate

• Grant number: 25/09766-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Engineering - Chemical Engineering - Chemical Technology
• Principal Investigator: Daniela Helena Pelegrine Guimarães
• Grantee: Lorena Matteucci Melo Ogando
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

Microalgae are promising sources of various high-value compounds with applications in bioenergy, biofuels, and nutraceutical products. However, the high cost of conventional cultivation media is one of the main obstacles to the economic feasibility of large-scale production. This project proposes the use of leachate as an alternative culture medium for Chlorella minutissima, aiming to optimize the production of biomolecules. Initially, C. minutissima will be cultivated in Guillard medium solely for culture maintenance and subculturing. The experiments will be conducted in airlift reactors, using leachate as the main culture medium, in order to evaluate its potential as a nutrient source for microalgal growth. The methodology includes an orthogonal experimental design (Taguchi L9), in which the effects of leachate concentration, CO¿ concentration, aeration rate, and photoperiod will be analyzed. The response variables will include biomass productivity, pigments, lipids, carbohydrates, and proteins. Although the project title refers to the use of a semicontinuous reactor, the stage addressed in this undergraduate research project will focus on the preliminary batch reactor phase, aiming to establish optimal conditions for subsequent semicontinuous cultivation. The study is expected to demonstrate the technical feasibility of using leachate as a sustainable cultivation medium, with potential for cost reduction and contribution to bioremediation. The main challenges include the variability of leachate composition, potential toxicity, and microbiological control. This study proposes an integrated approach to urban waste valorization and the production of biotechnologically relevant biomolecules.