Algal biomass as a food and feed supplement: Process engineering analysis

Abstract

Background: The global market for algae-based food and feed supplements is well-established and growing rapidly. The sector has grown fivefold since 2000. While microalgae products still hold a modest market share, the large-scale commercial production of microalgae as a primary source of proteins, lipids, carbohydrates, and other compounds remains in its early developmental stages. If successfully mass-produced, microalgae could make a significant contribution to global food and feed security.

Objective: The study aims to compare the potential of selected algal strains as sustainable sources of high-value biomass for food and feed using a low-cost, solvent-free analytical method based on Near-infrared spectroscopy.

Methods: Green unicellular microalgae Chlorella vulgaris Pa-023, Neochloris oleoabundans Pa-022, and cyanobacterium Limnospira maxima Pc-02 were selected and cultivated in bubble column photobioreactors using nitrogen-rich media under LED illumination with red and blue light spectrums. Near-infrared spectroscopy was applied as a non-destructive method to monitor protein, lipid, and carbohydrate content during cultivation.

Results: Quantitative analysis revealed distinct biochemical profiles among C. vulgaris, N. oleoabundans, and L. maxima, with protein contents of 49.2, 40.0, and 59.0 g/100 g dry weight, respectively. L. maxima showed the highest protein content, while N. oleoabundans had the highest lipid content (26.0 g/100 g dry weight), suggesting their suitability for protein-rich products and lipid-based applications. A cost-efficiency assessment of L. maxima cultivation in a 100-L photobioreactor (PUEVIT GmbH, Germany) yielded 98 g dry biomass in 7 days, with production costs estimated at €43.56.

Novelty: The study uniquely integrates comparative biochemical profiling of algal and cyanobacterial biomass with a cost-efficiency analysis of semi-industrial biomass production. Key innovations include: (i) species-specific application potential; (ii) the first techno-economic assessment of L. maxima cultivation in a controlled photobioreactor; (iii) a practical demonstration of economically viable microalgal biomass production.

Conclusion: Near-infrared spectroscopy has proven to be an effective method for non-destructive biomass analysis. However, improving model accuracy requires a broader calibration set with well-characterized standards. Expanding this dataset will enhance the predictive power and reliability of the method.

Keywords: algae, high-value biomass, NIR spectrophotometry, food and feed supplement, cost-efficiency.