Natural acid-thermo-stable blue and red pigments to replace artificial colorants

Overview

Natural, food-safe blue phycocyanin and red phycoerythrin pigments are being developed as replacements for artificial colorants in food and beverage applications. The pigments are produced using engineered versions of food-safe cyanobacterium Arthrospira platensis (Spirulina) and red microalgae Galdieria sulphuria, both recognized as Generally Recognized As Safe (GRAS) by the FDA. The pigments are engineered to be acid-thermo-stable, maintaining color integrity under acidic and high-temperature conditions typical of food processing.

Technical specifications

Key features:

• Acid-thermo-stable blue phycocyanin with a midpoint denaturation temperature of 85°C at pH 4, supporting stability in acidic and heat-processed food and beverage applications
• Red phycoerythrin production using similar expression and engineering approaches
• Bacterial expression library enabling rapid generation and testing of pigment variants for enhanced stability and purification efficiency
• Minor gene editing in photosynthetic GRAS organisms A. platensis and G. sulphuria to enhance pigment yield and stability
• Cost-effective purification process designed for scalability and low production costs
• Biorefinery approach that co-produces a neutral protein isolate, biochar, and bio-oil from process residues, maximizing revenue and minimizing waste
• GRAS-status organisms with FDA-recognized safety profiles for food applications

Production process:

• Sustainable closed-loop cultivation of A. platensis
• Non-energy-intensive harvesting
• Quick wash and re-suspension in deionized water
• Low-energy, low-temperature pulsed-electric field treatment for cell disruption
• 24-hour aqueous extraction
• Clarification via centrifugation and membrane microfiltration
• Separation of phycocyanin and water-soluble proteins via membrane ultrafiltration and/or immobilized metal affinity chromatography
• Hydrothermal liquefaction of solid residues to bio-oil

Technology readiness level

The technology has been validated at the bench scale. Enhanced acid-thermo-stability and cost-effective purification of blue phycocyanin have been demonstrated in E. coli using modified genes derived from A. platensis, acid-thermo-philic cyanobacterium Synechococcus lividus PCC6715, and microalgae Galdieria phlegrea. A bench-scale biorefinery process for manufacturing blue phycocyanin from A. platensis has also been demonstrated, producing high-yield and high-purity pigment alongside co-products including a neutral protein isolate, biochar, and bio-oil. Future validation work will focus on scaling and optimizing the full production pipeline, from cultivation through extraction, purification, and residue conversion.