Influence of GABA (Gamma-aminobutyric acid) supplementation on biomass, pigments, lipid and protein content of Pseudochlorella pringsheimii under salinity stress

Abstract

Microalgae synthesize valuable compounds like pigments, proteins, lipids and carbohydrates under stress conditions, which make them an interesting feedstock for different industries. The effect of GABA (Gamma-aminobutyric acid) supplementation under salinity stress conditions was investigated on growth, biomass, pigments, lipid and protein content of Pseudochlorella pringsheimii. Between the varying treatments, 5 g/L NaCl combined with 2.5 mM GABA was observed as the best concentration for stimulating the production of bioactive compounds in microalga P. pringsheimii. The results revealed a significant increase in biomass content by 93.24 %, compared with the control. Moreover, a significant increase was also observed in the production of chlorophyll (chl) a, chlorophyll (chl) b, total carotenoids (car), protein and lipid content by 112.15 %, 84 %, 29.94 %, 23.08 % and 35.63 %, respectively. However, as compared to control and salinity stress alone, the total carbohydrate content was sharply declined by 52.30 % and 101.79 % in GABA supplemented groups. In addition, the presence of fatty acids and different biomolecules were also confirmed by GC–MS and FTIR analysis. The existence of different essential and non-essential amino acids in substantial amounts was validated by UHPLC analysis. Collectively, the present work contributes to a novel strategy for boosting the coproduction of biomass, lipids, proteins and pigments in P. pringsheimii under unfavorable conditions.