Strategy for high-yield astaxanthin recovery directly from wet Haematococcus pluvialis without pretreatment

New strategies to study in depth the metabolic mechanism of astaxanthin biosynthesis in Phaffia rhodozyma

Astaxanthin, a ketone carotenoid known for its high antioxidant activity, holds significant potential for application in nutraceuticals, aquaculture, and cosmetics. The increasing market demand necessitates a higher production of astaxanthin using Phaffia rhodozyma. Despite extensive research efforts focused on optimizing fermentation conditions, employing mutagenesis treatments, and utilizing genetic engineering technologies to enhance astaxanthin yield in P. rhodozyma, progress in this area remains limited. This review provides a comprehensive summary of the current understanding of rough metabolic pathways, regulatory mechanisms, and preliminary strategies for enhancing astaxanthin yield. However, further investigation is required to fully comprehend the intricate and essential metabolic regulation mechanism underlying astaxanthin synthesis. Specifically, the specific functions of key genes, such as crtYB, crtS, and crtI, need to be explored in detail. Additionally, a thorough understanding of the action mechanism of bifunctional enzymes and alternative splicing products is imperative. Lastly, the regulation of metabolic flux must be thoroughly investigated to reveal the complete pathway of astaxanthin synthesis. To obtain an in-depth mechanism and improve the yield of astaxanthin, this review proposes some frontier methods, including: omics, genome editing, protein structure-activity analysis, and synthetic biology. Moreover, it further elucidates the feasibility of new strategies using these advanced methods in various effectively combined ways to resolve these problems mentioned above. This review provides theory and method for studying the metabolic pathway of astaxanthin in P. rhodozyma and the industrial improvement of astaxanthin, and provides new insights into the flexible combined use of multiple modern advanced biotechnologies.

Unveiling astaxanthin: biotechnological advances, delivery systems and versatile applications in nutraceuticals and cosmetics

Astaxanthin (ASX), "king of carotenoids", is a xanthophyll carotenoid that is characterized by a distinct reddish-orange hue, procured from diverse sources including plants, microalgae, fungi, yeast, and lichens. It exhibits potent antioxidant and anti-ageing properties and has been demonstrated to mitigate ultraviolet-induced cellular and DNA damage, enhance immune system function, and improve cardiovascular diseases. Despite its broad utilization across nutraceutical, cosmetic, aquaculture, and pharmaceutical sectors, the large-scale production and application of ASX are constrained by the limited availability of natural sources, low production yields and stringent production requirements. This review provides a comprehensive analysis of ASX applications, emphasizing its dual roles in cosmetic and nutraceutical fields. It integrates insights into the qualitative differences of ASX from various natural sources and assesses biosynthetic pathways across organisms. Advanced biotechnological strategies for industrial-scale production are explored alongside innovative delivery systems, such as emulsions, films, microcapsules, nanoliposomes, and nanoparticles, designed to enhance ASX's bioavailability and functional efficacy. By unifying perspectives on its nutraceutical and cosmetic applications, this review highlights the challenges and advancements in formulation and commercialization. Prospective research directions for optimizing ASX's production and applications are also discussed, providing a roadmap for its future development.

Advancement of Carotenogenesis of Astaxanthin from Haematococcus pluvialis: Recent Insight and Way Forward

The demand for astaxanthin has been increasing for many health applications ranging from pharmaceuticals, food, cosmetics, and aquaculture due to its bioactive properties. Haematococcus pluvialis is widely recognized as the microalgae species with the highest natural accumulation of astaxanthin, which has made it a valuable source for industrial production. Astaxanthin produced by other sources such as chemical synthesis or fermentation are often produced in the cis configuration, which has been shown to have lower bioactivity. Additionally, some sources of astaxanthin, such as shrimp, may denature or degrade when exposed to high temperatures, which can result in a loss of bioactivity. Producing natural astaxanthin through the cultivation of H. pluvialis is presently a demanding and time-consuming task, which incurs high expenses and restricts the cost-effective industrial production of this valuable substance. The production of astaxanthin occurs through two distinct pathways, namely the cytosolic mevalonate pathway and the chloroplast methylerythritol phosphate (MEP) pathway. The latest advancements in enhancing product quality and extracting techniques at a reasonable cost are emphasized in this review. The comparative of specific extraction processes of H. pluvialis biological astaxanthin production that may be applied to large-scale industries were assessed. The article covers a contemporary approach to optimizing microalgae culture for increased astaxanthin content, as well as obtaining preliminary data on the sustainability of astaxanthin production and astaxanthin marketing information.

Effects of Haematococcus pluvialis Addition on the Sensory Properties of Plant-Based Meat Analogues

Due to the increase in population and the deficiency of land resources, the cost of raising livestock is gradually increasing. Plant-based meat analogues (PBMAs) are considered excellent substitutes for animal meat. Our research investigated the effect of Haematococcus pluvialis (HP) on gluten-based soybean and wheat PBMA with contents of 1%, 3%, 5%, and 7%. Compared with the control group, HP significantly improved the color of the extrudates, showed visual characteristics similar to red meat, and achieved a soft texture and apparent rheological properties. The 7% HP had negative effects on the organizational degree and viscosity. In addition, the E-nose indicated that the different contents of HP changed the flavor of the extrudates. The extrudates with 3% and 5% HP were most similar to each other among all of the extrudates for volatile compounds, and the extrudates with 1% HP and 7% HP had significantly different flavors compared to the control group. Furthermore, 20 different volatile compounds were compared according to their retention indices and retention areas. The results showed that the proportions of alcohol, ester, terpenes, acid, and furan were increased. When the threshold was referenced, HP was considered to provide PBMAs with grassy and healing grain flavor properties. Therefore, the results proved that the addition of HP can improve PBMAs sensory properties.

Cell wall breaking of Haematococcus pluvialis biomass facilitated by Baijiu jiuqu fermentation with simultaneously production of beverages

The microalgae Haematococcus pluvialis is a commercial source of natural astaxanthin. However, mature cells develop rigid three-layer wall structures and a repulsive odor. This study applied a liquid static fermentation system to screen hydrolyzing microorganisms for cell wall hydrolysis. Baijiu jiuqu and Gutian hongqu were found to have promising potential for application. The fermentation using 2% baijiu jiuqu and 2% glucose for pre-activation achieved comparable recovery of carotenoids to homogenizer disruption methods and produced stable fragrance which may be attributed to ethyl octanoate, hexyl formate, and phenethyl butyrate, as revealed by gas chromatography-mass spectrometry analysis. The abundance of astaxanthin molecules was slightly affected by fermentation with fold change < 2, while molecules with higher fold change (>10) were mainly carbohydrates, lipids, and steroids proving the safety of the fermentation. This study provides a new scheme for the biorefining of Haematococcus. pluvialis, potentially contributing to the industrial production of natural astaxanthin.

Increasing production and bio-accessibility of natural astaxanthin in Haematococcus pluvialis by screening and culturing red motile cells under high light condition

The thick cell wall and low astaxanthin productivity were two important bottlenecks limiting industrial production of astaxanthin via Haematococcus pluvialis. This study reports a strategy for increasing production and bio-accessibility of astaxanthin in H. pluvialis by screening and culturing red motile cells under high light condition. Compared with the original strain NBU489, the biomass of the novel isolated strain RMS10 increased by 31.9% under low light condition, and the astaxanthin content (44.6 mg/g) increased by 53.3% after 9-day high light induction, which were readily extracted and digested without cell disruption. Subsequent transcriptomic analysis confirmed the accumulation of astaxanthin and lipids in RMS10 cells as expression of genes associated with biosynthesis of fatty acid and astaxanthin were up-regulated, while those involved in thick cell wall biosynthesis and reactive oxygen species scavenging were down-regulated in RMS10. Collectively, this study provides a simple and effective method for economical production of natural astaxanthin.