An innovative protocol to select the best growth phase for astaxanthin biosynthesis in H. pluvialis

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 dietary astaxanthin on growth performance, muscle composition, non-specific immunity, gene expression, and ammonia resistance of juvenile ivory shell (Babylonia areolate)

Astaxanthin is one of the important immunopotentators in aquaculture. However, little is known about the physiological changes and stress resistance effects of astaxanthin in marine gastropods. In this study, the effects of different astaxanthin concentrations (0, 25, 50, 75, and 100 mg/kg) on the growth, muscle composition, immune function, and resistance to ammonia stress in Babylonia areolata were investigated after three months of rearing. With the increase in astaxanthin content, the weight gain rate (WGR), specific growth rate (SGR), and survival rate (SR) of B. areolata showed an increasing trend. The 75-100 mg/kg group was significantly higher than the control group (0 mg/kg). There was no significant difference in the flesh shell ratio (FSR), viscerosomatic index (VSI), and soft tissue index (STI) of the experimental groups. Astaxanthin (75 mg/kg) significantly increased muscle crude protein content and increased hepatopancreas alkaline phosphatase (AKP), superoxide dismutase (SOD), and catalase (CAT) activity. Astaxanthin (75-100 mg/kg) significantly increased the total antioxidant capacity (T-AOC) and acid phosphatase (ACP) of the hepatopancreas and decreased the malondialdehyde (MDA) content of B. areolata. Astaxanthin significantly induced the expression levels of functional genes, such as SOD, Cu/ZnSOD, ferritin, ACP, and CYC in hepatopancreas and increased the survival rate of B. areolata under ammonia stress. The addition of 75-100 mg/kg astaxanthin to the feed improved the growth performance, muscle composition, immune function, and resistance to ammonia stress of B. areolata.

Effects of Extracts of Two Selected Strains of Haematococcus pluvialis on Adipocyte Function

Recently, microalgae are arousing considerable interest as a source of countless molecules with potential impacts in the nutraceutical and pharmaceutical fields. Haematococcus pluvialis, also named Haematococcus lacustris, is the largest producer of astaxanthin, a carotenoid exhibiting powerful health effects, including anti-lipogenic and anti-diabetic activities. This study was carried out to investigate the properties of two selected strains of H. pluvialis (FBR1 and FBR2) on lipid metabolism, lipolysis and adipogenesis using an in vitro obesity model. FBR1 and FBR2 showed no antiproliferative effect at the lowest concentration in 3T3-L1 adipocytes. Treatment with FBR2 extract reduced lipid deposition, detected via Oil Red O staining and the immunocontent of the adipogenic proteins PPARγ, ACLY and AMPK was revealed using Western blot analysis. Extracts from both strains induced lipolysis in vitro and reduced the secretion of interleukin-6 and tumor necrosis factor-α. Moreover, the FBR1 and FBR2 extracts improved mitochondrial function, reducing the levels of mitochondrial superoxide anion radical and increasing mitochondrial mass compared to untreated adipocytes. These findings suggest that FBR2 extract, more so than FBR1, may represent a promising strategy in overweight and obesity prevention and treatment.

Genetic Improvement to Obtain Specialized Haematococcus pluvialis Genotypes for the Production of Carotenoids, with Particular Reference to Astaxanthin

Nowadays, the search for natural substances with a high nutraceutical effect positively impact the world market. Among the most attractive macromolecules are antioxidants, capable of preventing the development of various pathologies. Astaxanthin (ASX) is antioxidant molecule produced by the microalga H. pluvialis as a response to different types of stress. Usually, astaxanthin production involves the first phase of accumulation of the biomass of H. pluvialis (green phase), which is then stressed to stimulate the biosynthesis and accumulation of ASX (red phase). In this study, the H. pluvialis wild-type strain was subjected to random mutagenesis by UV. Among the different mutant strains obtained, only two showed interesting bio-functional characteristics, such as a good growth rate. The results demonstrated that the HM1010 mutant not only has a higher growth trend than the WT mutant but accumulates and produces ASX even in the green phase. This innovative genotype would guarantee the continuous production of ASX, not linked to the two-step process and the uniqueness of the product obtained.