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Enhancing Haematococcus pluvialis biomass and γ-aminobutyric acid accumulation by two-step cultivation and salt supplementation

Ding, Wei, Cui, Jing, Zhao, Yongteng, Han, Benyong, Li, Tao, Zhao, Peng, Xu, Jun-Wei, Yu, Xuya
Bioresource technology 2019 v.285 pp. 121334
Haematococcus pluvialis, biomass, bioprocessing, carbohydrate content, culture media, fulvic acids, gamma-aminobutyric acid, gene expression regulation, genes, microalgae, salt stress, sodium chloride
The primary goal of this study was to assess the roles of chemical factors and bioprocess strategies on a mixotrophic culture of the microalga Haematococcus pluvialis during γ-aminobutyric acid (GABA) production. A two-stage strategy was used to increase the biomass and GABA accumulation of H. pluvialis. In stage I, mixotrophic growth of H. pluvialis in the presence of fulvic acid (FA) produced a high biomass (1.84 g L−1) with a GABA content of 25.45 mg g−1. Furthermore, a maximum GABA content of 38.57 mg g−1 was obtained when cells were cultured with 0.4 g L−1 NaCl under photoautotrophic conditions in stage II, whereas the carbohydrate content of cells sharply decreased from 26.68 to 18.22%. In addition, salt stress upregulated the expression of the gad and cam genes. The results of this study demonstrate an efficient strategy to produce GABA from the microalga H. pluvialis.