Rapid Quantification of Microalgae Growth with Hyperspectral Camera and Vegetation Indices

Area of Science:

• Aquatic sciences
• Biotechnology
• Spectroscopy

Background:

• Spectral cameras are vital for remote sensing and laboratory analysis of microalgae.
• Developing practical, cost-efficient hyperspectral data collection and analysis protocols is crucial for algae monitoring.

Purpose of the Study:

• To evaluate a commercial hyperspectral camera for monitoring microalgae growth in liquid cultures.
• To establish correlations between spectral indices and key growth parameters.

Main Methods:

• Utilized a commercial hyperspectral camera for transmission imaging of algae cultures.
• Calculated spectral indices (e.g., A/B, A/(A+B)) from various wavebands.
• Compared spectral data against measurements from cell counters, chlorophyll a concentration, and chlorophyll fluorescence.

Main Results:

• A near-infrared/red waveband ratio showed strong, strain-specific correlations with algae abundance (r = 0.85–0.96).
• Various spectral indices demonstrated good correlations with algae biomass (r = 0.66–0.98).
• The near-infrared/red index correlated well with chlorophyll a concentration and chlorophyll fluorescence (r = 0.97).

Conclusions:

• A simple hyperspectral imaging setup and vegetation index analysis can effectively monitor algae cultures.
• The near-infrared/red index is a powerful, interpretable tool for assessing algae biomass and growth.
• Spectral imaging provides a cost-efficient alternative to traditional methods for laboratory-scale algae monitoring.