Influencing of amino acid composition of green freshwater algae and cyanobacterium by methods of cultivation

Abstract

Aim: To determine and evaluate amino acid profiles in algal biomass of green freshwater microalgae Chlorella kessleri, Scenedesmus quadricauda and Chlorella sp. and blue-green micro-alga (cyanobacterium) Spirulina platensis cultivated by various methods. To perform the comparison of amino acid contents in algal biomass originated from cultivation methods. Material and Methods: Selected species of green freshwater micro-algae and blue-green microalgea were cultivated under the autotrophic cultivation in laboratory, in an outdoor open circulating cascade-type cultivation apparatus in a thin-layer, in a solar photobioreactor and under the heterotrophic cultivation regime in a fermenter. Contents of seventeen amino acids in algal samples were determined by using ion-exchange chromatography. Results: Autotrophic growth regime in a solar photobioreactor and in an outdoor open circulating cascade-type cultivation apparatus in a thin-layer provided algal biomass with higher amino acid contents than cultivation in a laboratory regime and heterotrophic cultivation in a fermenter. Conclusion: Microalgae are considered as an unconventional source of amino acids, so it is important to monitor their amino acid composition. This work provides amino acid profiles of investigated green freshwater microalgae and blue-green microalgea in dependence on their cultivation methods. The content of amino acids in algal biomass is directly associated with the selected cultivation method and growth conditions (e.g. chemical composition of culture medium, quality of light, pH, turbulence, salinity and temperature) of algal cells. Further studies are needed to elucidate the influence of individual growth conditions that may lead to changes in amino acid composition in algal biomass.