Commercial Potential of the Cyanobacterium Arthrospira maxima: Physiological and Biochemical Traits and the Purification of Phycocyanin

Simple Summary

Arthrospira maxima is an unbranched, filamentous cyanobacterium rich in important cellular products such as vitamins, minerals, iron, essential amino acids, essential fatty acids, and protein, which has made it one of the most important commercial photoautotrophs. To optimize the growth conditions for the production of target compounds and to ensure profitability in commercial applications, the effects of pH and temperature were investigated. A. maxima has been shown to be tolerant to a range of pH conditions and to exhibit hyper-accumulation of phycoerythrin and allophycocyanin at low temperatures. These traits may offer significant advantages for future exploitation, especially in outdoor cultivation with fluctuating pH and temperature. Our study also demonstrated a new method for the purification of phycocyanin from A. maxima by using by ultrafiltration, ion-exchange chromatography, and gel filtration, producing PC at 1.0 mg·mL⁻¹ with 97.6% purity.

Abstract

Arthrospira maxima is a natural source of fine chemicals for multiple biotechnological applications. We determined the optimal environmental conditions for A. maxima by measuring its relative growth rate (RGR), pigment yield, and photosynthetic performance under different pH and temperature conditions. RGR was highest at pH 7–9 and 30 °C. Chlorophyll a, phycocyanin, maximal quantum yield (F_v/F_m), relative maximal electron transport rate (rETR_max), and effective quantum yield (Φ_PSII) were highest at pH 7–8 and 25 °C. Interestingly, phycoerythrin and allophycocyanin content was highest at 15 °C, which may be the lowest optimum temperature reported for phycobiliprotein production in the Arthrospira species. A threestep purification of phycocyanin (PC) by ultrafiltration, ion-exchange chromatography, and gel filtration resulted in a 97.6% purity of PC.

Contrasting effects of monochromatic LED lighting on growth, pigments and photosynthesis in the commercially important cyanobacterium Arthrospira maxima

The aim of this study was to evaluatethe effects of different colored light emitting diodes (LEDs) on the growth, pigment yield, and photosynthetic performance of Arthrospira maxima, a commercially exploited species of cyanobacteria. The highest growth and chlorophyll a (Chl a) concentration were obtained under red LED and white fluorescent light, while the lowest growth and Chlaconcentration were observed under blue LED. However, blue LED produced the highest levels of phycobiliproteins (3.20 mg·g^-1phycocyanin [PC]; 0.19 mg·g^-1 allophycocyanin [APC]; 0.97 mg·g^-1for phycoerythrin [PE], effective quantum yield (Φ_PSII) and maximum relative electron transport rate (rETR_max) inA. maxima. The results of this study suggest that red and blue LEDs increase the biomass yield and pigment content of cyanobacteria, respectively, and the combined use of red and blue light may significantly improve algal biomass and biopigment yield.