Recently, the research group of Prof. HUANG Qing from the Institute of Intelligent Machines (IIM), Hefei Institutes of Physical Science (HFIPS) found that the γ-aminobutyric acid (GABA) can promote the growth of Haematococcus pluvialis and increase the astaxanthin accumulation.

Published in the journal Algae Research, the team reported how they tried different ways to promote the growth of Haematococcus pluvialis till they found that GABA can effectively increase the biomass of it, leading to promotion of astaxanthin yield.

Haematococcus pluvialis is one of the best sources for obtaining nature astaxanthin, which has medicinal and nutritional functions in health due to its strong antioxidant capacity. To complete the accumulation of astaxanthin in Haematococcus pluvialis, strong light irradiation is required. But strong light will cause irreversible photo-oxidative damage to the algae cells, resulting in the reduction of astaxanthin production.

So, how to improve the astaxanthin production from Haematococcus pluvialis remains a challenge for researchers.

This study also sheds light on the mechanism of GABA working on Haematococcus pluvialis.

The researchers found that at the late green growth stage, GABA could enhance the ability of algae cells to resist stress with the increased expression of PP2C, SnRK2, CPK, HASP90, PTOX genes related to stress resistance, while in the early red cyst stage, GABA had a photoprotective effect on algae cells exposed to strong light as the expression of light harvesting protein Lhca2 was up-regulated.

The addition of GABA can not only increase the biomass, but also reduce the photo-oxidation damage and cell death in the process of strong light conversion. As such, GABA improves the photosynthetic performance of algal cells, giving rise to better light adaptability and stronger heat dissipation capacity.

This work was supported by the National Natural Science Foundation of China.

Fig. 1. The growth reactor and experimental process (Image by HUANG Qing)