Biomass and phycocyanin content of heterotrophic Galdieria sulphuraria 074G under maltodextrin and granular starches–feeding conditions

Abstract

A major disadvantage of microalgal cultivation is limited biomass yields due to the autotrophic lifestyle of most microalgal species. Heterotrophic growth on a suitable carbon source and oxygen can overcome such limitations. The red microalga Galdieria sulphuraria strain 074G grows heterotrophically on glucose and a number of other carbon sources while constitutively producing photopigments, including the blue-colored phycocyanin, a natural food colorant. Galdieria sulphuraria strain 074G grew well on maltodextrins as well as on granular starch in combination with the enzyme cocktail Stargen002. The maltodextrin cultures produced 2 mg phycocyanin per gram substrate, being slightly more than on glucose. The phycocyanin extracted from maltodextrin-grown cultures was thermostable up to 55 °C. Maltodextrins can be a cheap alternative to glucose syrups for the production of phycocyanin as natural food colorant.