Development of a small-scale spectrophotometer to monitor microalgae cultures on CubeSats

This study aims to evaluate the viability of utilizing Chlorella vulgaris microalgae cultures loaded onto the UERJ Sats CubeSat. The objective is to develop a compact equipment capable of real-time monitoring of (C. vulgaris) culture for potential use in a CubSat Payload. The calibration of the equipment involved using seven samples of laboratory-grown Chlorella vulgaris microalgae at different densities ranging from 10
⁶
to 10
⁷
algae/mL. The calibration process included comparing the spectrophotometry readings obtained from the developed equipment with measurements obtained from a commercial benchtop spectrophotometer. Additionally, microalgae cell counting was performed using a Neubauer chamber in a Nikon optical microscope at 400x magnification. Based on the results presented in this work, it can be concluded that the spectrophotometer built at LARISA/DETEL (Laboratory of Industrial Networks and Automation Systems), utilizing the OPT101 light sensor, was successfully calibrated at LABIFI/DESMA (Laboratory of Bioremediation, Phytotechnologies and Innovation in Water and Effluent Treatment). The calibrated spectrophotometer demonstrated reliable performance on laboratory bench, showing good agreement with spectrophotometry measurements and cell counts, concerning the measurements by spectrophotometry (R
²
= 0.9996) and with the cell count (R
²
= 0.988).