Production, isolation and characterization of C-phycocyanin from a new halo-tolerant Cyanobacterium aponinum using seawater

Tailoring nitrogen and phosphorus levels for tunable glycogen and protein production in halophilic Cyanobacterium aponinum PCC10605

Cyanobacteria hold promise for simultaneous carbon capture and chemicals production, but the regulation and effect of nitrogen (N) and phosphorus (P) remains unclear. This study investigates major productions of glycogen, protein, and C-phycocyanin (C-PC) in Cyanobacterium aponinum PCC10605 under different N/P levels, alongside changes in light and CO2. Increasing nitrate (NO3-) from 2 to 6 mM resulted in a 9.7-fold increase in C-PC and reduced glycogen to 8.9 %. On the other hand, elevating phosphorus from 0.1 to 2 mM under limited nitrogen enhanced biomass and glycogen through the upregulation of carbonic anhydrase, ADP-glucose pyrophosphorylase, and glycogen phosphorylase. Changes in phosphorus levels and CO2 inlet concentrations affected metabolites accumulation and carbon capture efficiency, leading to the best condition of 76 % uptake capacity in direct air capture (DAC). All findings underscore the trade-off between glycogen and protein, representing the importance of N/P levels in nutrient modulation of PCC10605.

Influence of Critical Parameters on the Extraction of Concentrated C-PE from Thermotolerant Cyanobacteria

This work aimed to identify the influence of pH, molarity, w/v fraction, extraction time, agitation, and either a sodium (Na2HPO4·7H2O-NaH2PO4·H2O) or potassium buffer (K2HPO4-KH2PO4) used in the extraction of C-phycoerythrin (C-PE) from a thermotolerant strain of Potamosiphon sp. An experimental design (Minimum Run Resolution V Factorial Design) and a Central Composite Design (CCD) were used. According to the statistical results of the first design, the K-PO4 buffer, pH, molarity, and w/v fraction are vital factors that enhance the extractability of C-PE. The construction of a CCD design of the experiments suggests that the potassium phosphate buffer at pH 5.8, longer extraction times (50 min), and minimal extraction speed (1000 rpm) are ideal for maximizing C-PE concentration, while purity is unaffected by the design conditions. This optimization improves extraction yields and maintains the desired bright purple color of the phycobiliprotein.

Phycocyanin from microalgae: A comprehensive review covering microalgal culture, phycocyanin sources and stability

As food safety continues to gain prominence, phycocyanin (PC) is increasingly favored by consumers as a natural blue pigment, which is extracted from microalgae and serves the dual function of promoting health and providing coloration. Spirulina-derived PC demonstrates exceptional stability within temperature ranges below 45 °C and under pH conditions between 5.5 and 6.0. However, its application is limited in scenarios involving high-temperature processing due to its sensitivity to heat and light. This comprehensive review provides insights into the efficient production of PC from microalgae, covers the metabolic engineering of microalgae to increase PC yields and discusses various strategies for enhancing its stability in food applications. In addition to the most widely used Spirulina, some red algae and Thermosynechococcus can serve as good source of PC. The genetic and metabolic manipulation of microalgae strains has shown promise in increasing PC yield and improving its quality. Delivery systems including nanoparticles, hydrogels, emulsions, and microcapsules offer a promising solution to protect and extend the shelf life of PC in food products, ensuring its vibrant color and health-promoting properties are preserved. This review highlights the importance of metabolic engineering, multi-omics applications, and innovative delivery systems in unlocking the full potential of this natural blue pigment in the realm of food applications, provides a complete overview of the entire process from production to commercialization of PC, including the extraction and purification.

Optimization of 4-aminobutyric acid feeding strategy and clustered regularly interspaced short palindromic repeats activation for enhanced value-added chemicals in halophilic Chlorella sorokiniana

Chlorella sorokiniana (CS) is a prominent microalga with vast potential as a biocarrier for carbon mitigation toward a green process. However, challenges remain in achieving high biomass levels and production rates. Therefore, a systematic feeding strategy using 4-aminobutyric acid (GABA) and CRISPR technology was applied to improve microalgal productivity. At first, GABA increased protein content by 1.4-fold, while intermittent supplementation during cultivation resulted in a 1.58-fold and 2.13-fold increase in biomass and pigment content, respectively. Under halophilic conditions, the optimal approach involved repeated feeding of 5 mM GABA at the initial and mid-log phases of growth, resulting in biomass, protein, and pigment levels of 6.74 g/L, 3.24 g/L, and 49.87 mg/L. CRISPRa mediated glutamate synthase and using monosodium glutamate (MSG) as a cheap precursor for GABA has effectively enhanced the biomass, protein, and lutein content, thus offers a cost-effective approach to commercialize high-valued chemical using algae towards a low-carbon paradigm.

Sustainable Production of Pigments from Cyanobacteria

Pigments are intensely coloured compounds used in many industries to colour other materials. The demand for naturally synthesised pigments is increasing and their production can be incorporated into circular bioeconomy approaches. Natural pigments are produced by bacteria, cyanobacteria, microalgae, macroalgae, plants and animals. There is a huge unexplored biodiversity of prokaryotic cyanobacteria which are microscopic phototrophic microorganisms that have the ability to capture solar energy and CO2 and use it to synthesise a diverse range of sugars, lipids, amino acids and biochemicals including pigments. This makes them attractive for the sustainable production of a wide range of high-value products including industrial chemicals, pharmaceuticals, nutraceuticals and animal-feed supplements. The advantages of cyanobacteria production platforms include comparatively high growth rates, their ability to use freshwater, seawater or brackish water and the ability to cultivate them on non-arable land. The pigments derived from cyanobacteria and microalgae include chlorophylls, carotenoids and phycobiliproteins that have useful properties for advanced technical and commercial products. Development and optimisation of strain-specific pigment-based cultivation strategies support the development of economically feasible pigment biorefinery scenarios with enhanced pigment yields, quality and price. Thus, this chapter discusses the origin, properties, strain selection, production techniques and market opportunities of cyanobacterial pigments.

CO2 fixation and cultivation of Thermosynechococcus sp. CL-1 for the production of phycocyanin

Cultivation of Cyanobacteria is preferable for CO2 fixation process due to its efficiency and production of beneficial byproducts like phycocyanin. In this study, Thermosynechococcus sp. CL-1 (TCL-1) was cultivated in a 30 L flat panel photobioreactor using a 3-fold-modified Fitzgerald medium with 113.2 mM dissolved inorganic carbon. The highest CO2 fixation rate of 21.98 ± 1.52 mg/L/h was followed by higher lipid content (49.91 % dry weight content or %dwc) than the generated carbohydrate (24.22 %dwc). TCL-1 also potentially produced phycocyanin that was dominated by C-phycocyanin (98.10 ± 6.67 mg/g) along with a lower amount of allophycocyanin and phycoerythrin under extraction using various types of solvent. Stability of phycocyanin extract was further examined during storage under various temperatures and light illuminations. Extraction with 36 % glucose solvent presented a protective effect to phycocyanin from heat and photo-damage which was proven by the kinetics study of phycocyanin degradation in this study.