Inhibition of antioxidant enzyme activities enhances carotenogenesis in microalga Dactylococcus dissociatus MT1

Abstract

Microalgal biotechnology has become a promising field of research for the production of valuable, sustainable and environmentally friendly byproducts, especially for carotenoids. Bulk accumulation of secondary carotenoids in microalgae are mostly induced by oxidative stress of cells. In this research, we investigated the effects of antioxidant enzyme activity inhibition on carotenogenesis in a microalga Dactylococcus dissociatus MT1. The activities of four major antioxidant enzyme families, namely superoxide dismutase (SOD), catalases (CAT), glutathione peroxydases (GPX) and ascorbate perxodases (APX), were inhibited by relevant inhibitors during the stressed cultivation of D. dissociatus to observe the effects on carotenogensis. A 91% decrease in activity was observed for CAT, comparing with controls without any inhibitors added, followed by 65%, 61%, and 47% for the enzymes SOD, APX, and GPX, respectively. Concomitantly, it was found that this partial inhibition had substantial influences on the accumulation of carotenoids, with the highest production levels obtained in CAT inhibition conditions and an increase of 2.6 times of carotenoid concentration observed, comparing with control cultivation conditions. We conclude that the modulation of antioxidant enzyme activities could lead to the overproduction of carotenoids in this microalgal cell culture, and we expect that this novel approach of optimizing carotenogenesis processes for D. dissociatus cell cultures could be transferrable to other cell culture systems and might have an important impact on the carotenoid production industry.

Integrated Transcriptomics and Metabolomics Analysis Reveal the Regulatory Mechanisms Underlying Sodium Butyrate-Induced Carotenoid Biosynthesis in Rhodotorula glutinis

“…Carotenoids play a crucial role in scavenging ROS, increasing tolerance to oxidative stress and maintaining the structure and functionality of the cell membrane. Many studies only investigated the induction of carotenoid production by increasing ROS levels through external stimuli such as nutritional stress, osmotic stress, or UV irradiation [62,63]; however, they overlooked the possibility of achieving the same goal by influencing unexplored parameters, such as by inhibiting antioxidant enzyme activity [43]. We elucidated the regulatory mechanism underlying the increase in carotenoid biosynthesis induced by SB, linking epigenetic modifiers with antioxidant enzyme activity.…”

“…This system acts as a supplementary antioxidant defense mechanism to counteract ROS and maintain the overall antioxidant capacity [32]. Studies have shown that inhibiting antioxidant enzyme activities enhances carotenoid biosynthesis in the microalga Dactylococcus dissociatus, particularly catalase [43]. In the YM25079 strain, catalase (EVM0001641, log2 FC = −3.8, EVM0001756, log2 FC = −1.3) is inhibited, which may positively influence the overproduction of carotenoid while weakening the antioxidant capacity of the strain.…”

Antioxidants from microalgae and their potential impact on human well-being

“…Some microalgae-derived antioxidants possess metal-chelating properties, meaning they can bind to transition metal ions (e.g., iron, copper) that contribute to the generation of ROS through Fenton reactions. By chelating these metals, antioxidants prevent ROS formation and reduce oxidative damage [65][66][67].…”

“…Microalgae-derived antioxidants, such as astaxanthin and phycocyanin, have demonstrated potent freeradical scavenging abilities and anti-aging effects in preclinical studies. These compounds could find applications in skincare products, dietary supplements, and pharmaceutical formulations targeting agerelated conditions [67,88].…”