Biomolecules from extremophile microalgae: From genetics to bioprocessing of a new candidate for large-scale production

Extremophile microalgae are potential candidates for large-scale production because the extreme growth conditions help avoiding contamination, especially in open pond reactors. Considering the role of microalgae cultivation in integrated production systems, especially reusing wastewater and gaseous effluents, the search for new potential strains is of great value. The microalga Galdieria sulphuraria is able to grow both in acidic (pH 0-4) and high-temperature environments (45-56 degrees C). It is of great interest in biology and biotechnology because is considered one of the oldest eukaryotes on Earth and can be used to produce biomolecules. A bibliometric study identified 3 main areas of study about this microalga: genetics (genome sequencing, horizontal gene transfer), bioactive molecules (phycocyanin, specific branched glycogen, and antioxidants) and wastewater treatment (removal of carbon, nitrogen, phosphorus, and heavy metals). A critical analysis of the advances on the scientific knowledge about G. suplhuraria indicates that the combination of (i) polyextremophile conditions for growth, (ii) metabolic versatility, (iii) removal of nutrients/metals from wastewaters and (iv) production of high value-added products makes this microalga a potential candidate for large scale production in integrated and sustainable systems.