Enhancement of Astaxanthin and Fatty Acid Production in Haematococcus pluvialis Using Strigolactone

Abstract

Improving the production rate of high-value nutraceutical compounds, such as astaxanthin and polyunsaturated fatty acids (PUFAs), is important for the commercialization of Haematococcus pluvialis biorefineries. Here, the effects of a phytohormone, strigolactone analog rac-GR24, on cell growth and astaxanthin and fatty acid biosynthesis in H. pluvialis were investigated. Four concentrations (2, 4, 6, and 8 µM) of rac-GR24 were initially added during 30 days of photoautotrophic cultivation. The addition of rac-GR24 improved cell number density and chlorophyll concentration in H. pluvialis cultures compared to the control; the optimal concentration was 8 µM. Despite a slightly reduced astaxanthin content of 30-d-old cyst cells, the astaxanthin production (26.1 ± 1.7 mg/L) improved by 21% compared to the rac-GR24-free control (21.6 ± 1.5 mg/L), owing to improved biomass production. Notably, at the highest dosage of 8 µM rac-GR24, the total fatty acid content of the treated H. pluvialis cells (899.8 pg/cell) was higher than that of the untreated cells (762.5 pg/cell), resulting in a significant increase in the total fatty acid production (361.6 ± 48.0 mg/L; 61% improvement over the control). The ratio of PUFAs, such as linoleic (C18:2) and linolenic (C18:3) acids, among total fatty acids was high (41.5–44.6% w/w) regardless of the rac-GR24 dose.

Salicylic acid treatment and overexpression of a novel polyamine transporter gene for astaxanthin production in Phaffia rhodozyma

“…Until now, many phytohormones, such as fulvic acid, 2, 4-epibrassinolide (EBR), strigolactone, salicylic acid (SA) and jasmonic acid (JA) have been reported to improve the biomass and astaxanthin accumulation in H . pluvialis ( Gao et al, 2013 ; Zhao et al, 2019a ; Mahadi et al, 2022 ). As a docosahexaenoic acid (DHA) industrial producer, Aurantiochytrium sp.…”

Room-Temperature Cell Disruption and Astaxanthin Recovery from Haematococcus lacustris Cysts Using Ultrathin α-Quartz Nanoplates and Ionic Liquids

“…Eventually, these cells were transformed into bright red, astaxanthin-rich cyst cells. In general, the intensity of red color in the H. lacustris cells and the amount of astaxanthin are proportional [24] After 90 days of culture, mature red H. lacustris cyst cells were harvested by centrifugation (3000 rpm for 10 min; Combi-514R, Hanil Science Inc., Daejeon, Korea) and lyophilized for 4 days (FD5512, IlShin BioBase Co., Yangju-si, Korea). The freeze-dried algal cells were stored in a vacuum bag at −20 • C before the astaxanthin extraction experiments.…”

Exploration of the phytohormone regulation of energy storage compound accumulation in microalgae

“…Auxin is one of the earliest discovered and most studied plant hormones (Mahadi et al, 2022; Zeng et al, 2021) and has the function of promoting cell division and cell expansion in plants (George et al, 2008). Indole‐3‐acetic acid (IAA), indole‐3‐butyric acid (IBA), indole‐3‐propionic acid (IPK), and indole‐3‐acetamide (IAM) were uncovered in 46 species of microalgae affiliated with divisions of Cyanophyta and Chlorophyta (Romanenko et al, 2015).…”

“…The chemical essence of abscisic acid (ABA) is a 15‐carbon sesquiterpenoid compound that is widely distributed in higher plants and has significant effects on the physiological metabolism of algae (Wang et al, 2022). ABA can mitigate the deleterious effects of environmental stress on higher plants and microalgae (Khasin et al, 2018) and generate resistance to adverse conditions, such as drought, cold, disease, and salt stresses (Mahadi et al, 2022; Liu, Chen, et al, 2018). The plant hormone ABA has been shown to improve the activity of starch biosynthesis in duckweed, reduce the activity of starch catalytic enzymes, and promote the accumulation of starch degradation.…”