Non-destructive monitoring of microalgae biofilms

• Published in: Bioresource technology Vol. 398; p. 130520
• Main Authors: Morgado, David, Fanesi, Andrea, Martin, Thierry, Tebbani, Sihem, Bernard, Olivier, Lopes, Filipa
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2024
• Subjects: Astaxanthin; Haeamatococcus pluvialis; Reflectance Indices; Rotating Biofilm; Spectroscopy; Spectroscopy; Haeamatococcus pluvialis; Rotating Biofilm; Astaxanthin; Reflectance Indices
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2024.130520

[Display omitted] •Proposed a protocol to fill the gap in the monitoring of microalgae biofilm systems.•Used reflectance spectroscopy to non-destructively quantify biofilm traits.•Identified reflectance indices that accurately tracked biofilm trait dynamics.•Robust prediction of astaxanthin under different light and nutrient conditions. Biofilm-based cultivation systems are emerging as a promising technology for microalgae production. However, efficient and non-invasive monitoring routines are still lacking. Here, a protocol to monitor microalgae biofilms based on reflectance indices (RIs) is proposed. This framework was developed using a rotating biofilm system for astaxanthin production by cultivating Haematococcus pluvialis on cotton carriers. Biofilm traits such as biomass, astaxanthin, and chlorophyll were characterized under different light and nutrient regimes. Reflectance spectra were collected to identify the spectral bands and the RIs that correlated the most with those biofilm traits. Robust linear models built on more than 170 spectra were selected and validated on an independent dataset. Astaxanthin content could be precisely predicted over a dynamic range from 0 to 4% of dry weight, regardless of the cultivation conditions. This study demonstrates the strength of reflectance spectroscopy as a non-invasive tool to improve the operational efficiency of microalgae biofilm-based technology.