Progress in the development of Haematococcus astaxanthin resources

Recently, the algae and algae biotechnology team of the Institute of Oceanology, Chinese Academy of Sciences has made progress in the development of Haematococcus astaxanthin resources and discovered that anaerobic respiration glycolysis (EMP), aerobic respiration tricarboxylic acid cycle (TCA), pentose Phosphoric acid pathway (PPP) and mitochondrial respiratory alternate oxidase pathway (AOX) and other non-light-dependent metabolic pathways have important regulatory effects on the synthesis and accumulation of Haematococcus astaxanthin
.

Related results were published on Bioresource Technology in the form of 3 research papers
.

Astaxanthin is bright red, has strong coloring, antioxidant capacity and various biological functions.
It has broad application prospects in the fields of nutrition and health food, medicine and health care, and cosmetics
.

Haematococcus is a single-celled green algae rich in astaxanthin, and it is also the best biological resource for the production of natural astaxanthin in the world
.

In the past, it was believed that the biosynthetic process of Haematococcus astaxanthin was mainly driven by strong light and induced by nutrient deficiency.
Most domestic and foreign studies focused on light-dependent anabolic processes (such as photosynthesis, photoprotection, and cell growth).
Pay less attention to decomposing expendable respiration
.

Even if the respiration is concerned in recent years, it only involves light-dependent photorespiration and chloroplast respiration, and the effect of non-light-dependent respiratory metabolic pathways on the synthesis and accumulation of Haematococcus astaxanthin is rarely reported
.

The research team discovered and confirmed that a variety of non-light-dependent respiratory metabolism pathways can effectively regulate the synthesis and accumulation of astaxanthin in Haematococcus
.

Studies have found that the activity of the alternative oxidase pathway of mitochondrial respiration is significantly negatively correlated with the accumulation of Haematococcus astaxanthin.
When the alternative oxidase pathway is inhibited, the content of intermediate metabolites closely related to respiration, pyruvate and glyceraldehyde triphosphate Both are significantly improved, and at the same time promote the production of energy substance NADPH, and stimulate the accumulation of active oxygen, which is beneficial to promote the synthesis of astaxanthin
.

Therefore, a new view is put forward that regulating respiration can promote the accumulation of Haematococcus astaxanthin biosynthesis
.

In addition, the researchers mainly used the method of exogenous addition of intermediate metabolites of respiration to further confirm that the central hub of energy metabolism of non-light-dependent respiration-the TCA cycle, can provide a carbon skeleton for the process of astaxanthin synthesis and promote astaxanthin.
Accumulate in large amounts in cells
.

The regulation mechanism is specifically as follows: the intermediate metabolite fumaric acid can increase the three main pathways of respiratory metabolism, EMP, TCA, and PPP, so that the levels of pyruvate and glyceraldehyde triphosphate are significantly increased.
The formation of phosphoric acid directly promotes the synthesis of astaxanthin.
On the other hand, it also promotes the synthesis of fatty acids, which in turn accelerates the process of astaxanthin esterification and indirectly promotes the synthesis of astaxanthin
.

Oxaloacetate, another metabolite of the TCA cycle, can directly promote the synthesis of Haematococcus astaxanthin by increasing the level of substrate and NADPH
.

Relatively speaking, oxaloacetic acid has a faster promoting effect than fumaric acid, and the effect is more significant, mainly due to the more efficient transmembrane mechanism of oxaloacetic acid
.

The above results have perfected the basic theory and development technology system for the large-scale development of Haematococcus astaxanthin, and will be conducive to perfecting the Haematococcus development model based on cell cycle control and large-scale closed photobioreactor construction, and make plant cells The operation of the photosynthetic plant is more efficient, which promotes the improvement of the development level of the industry
.

At the same time, the research results also have enlightenment and reference value for the research and resource development of other microalgae carotenoids and other secondary metabolites
.

This research work has been funded by the National Key Research and Development Program, the National Natural Science Foundation of China and the Joint Fund
.

 The model of non-light-dependent respiration regulating the synthesis and accumulation of astaxanthin in Haematococcus.
Source: Institute of Oceanology, Chinese Academy of Sciences