Directed Coevolution of β-Carotene Ketolase and Hydroxylase and Its Application in Temperature-Regulated Biosynthesis of Astaxanthin

Advances and trends for astaxanthin synthesis in Phaffia rhodozyma

Astaxanthin, a carotenoid endowed with potent antioxidant capacity, exhibits considerable application prospects in nutraceuticals, pharmaceuticals, and cosmetics. In contrast to the chemical synthesis method, the biosynthesis of astaxanthin is undoubtedly a greener and more environmentally friendly production approach. In this review, we comprehensively review the biosynthetic pathways and multiple strategies for astaxanthin synthesis in Phaffia rhodozyma. Some biotechnology advancements for increasing the yield of astaxanthin in Phaffia rhodozyma encompass mutagenesis breeding, genetic modification, and optimizing fermentation conditions, thereby opening up new avenues for its application in functional foods and feed. Nevertheless, the yield of product synthesis is constrained by the host metabolic stoichiometry. Besides breaking the threshold of astaxanthin production and alleviating the impact of astaxanthin accumulation on cell growth, a comprehensive comprehension of multiple interconnected metabolic pathways and complex regulatory mechanisms is indispensable for significantly enhancing astaxanthin production. This review presents some prospects of integrating digital concepts into astaxanthin production to aid in overcoming current challenges.

Astaxanthin alleviates fipronil-induced neuronal damages in male rats through modulating oxidative stress, apoptosis, and inflammatory markers

Fipronil (FPN) is an effective pesticide for veterinary and agricultural use; however, it can induce neurotoxic effects on non-target organisms after accidental exposure. Astaxanthin (AST) is a dark red carotenoid with antioxidant, anti-inflammatory, neuroprotective, and antiapoptotic effects. This study investigated the ameliorative impact of AST against FPN-induced brain damage in rats. Thirty-two adult Wistar rats were allocated into four groups (n = 8): Control, AST (20 mg/kg bwt/day), fipronil (FPN) (20 mg/kg bwt/day), and AST + FPN group. Acetylcholine (ACh), dopamine, malondialdehyde (MDA), and proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and inflammatory cytokine cyclooxygenase-2 (COX2) levels were enhanced in the FPN-administered group relative to the control group. In addition, a substantial reduction of acetylcholine esterase (AchE), gamma-aminobutyric acid (GABA), serotonin, reduced glutathione (GSH) levels, catalase (CAT), and total superoxide dismutase (T-SOD) enzyme activities were determined. FPN induced histopathological alterations in the cerebral and cerebellar tissues. Likewise, the histomorphometric image analysis of H and E-stained tissue sections was constant with FPN-induced neurotoxicity. Immunohistochemically, an intense positive immunohistochemical staining of apoptotic marker caspase-3 and astrocytes activation marker glial fibrillary acidic protein (GFAP) in the examined tissues was noticed. Inversely, the simultaneous administration of AST partially attenuated FPN impacts, ameliorating the severity of FPN-induced neuronal damage. These results were also established with the molecular docking findings. It could be suggested that AST has antioxidant, anti-inflammatory, and anti-apoptotic capabilities against FPN-induced neuronal damage via suppression of oxidative stress and pro-inflammatory cytokines, preservation of the neurotransmitters, and the cerebral and cerebellar histoarchitectures.

Synthetic Biology Strategies for the Production of Natural Colorants and Their Non-Natural Derivatives

Colorants are widely used in our daily lives to give colors to diverse chemicals and materials, including clothes, food, drugs, cosmetics, and paints. Although synthetic colorants derived from fossil fuels have been predominantly used due to their low cost, there is a growing need to replace them with natural alternatives. This shift is driven by increasing concerns over the climate crisis caused by excessive fossil fuel use, as well as health issues associated with the consumption of foods, beverages, and cosmetics containing petroleum-derived chemicals. In addition, many natural colorants show health-promoting properties such as antioxidant and antimicrobial activities. Despite such advantages, natural colorants could not be readily commercialized and distributed in the market due to their low stability, limited color spectrum, and low yields from natural resources. To this end, synthetic biology approaches have been developed to efficiently produce natural colorants from renewable resources with high yields. Strategies to diversify natural colorants to produce non-natural derivatives with enhanced properties and an expanded color spectrum have been also developed. In this Review, we discuss the recent synthetic biology strategies developed for enhancing the production of natural colorants and their non-natural derivatives, together with accompanying examples. Challenges ahead and future perspectives are also discussed.

Recent Advancements in the Biomanufacturing of Crocetin and Crocins: Key Enzymes and Metabolic Engineering

Crocetin and crocins are high-value apocarotenoids recognized for their role as food colorants as well as for their numerous industrial and therapeutic applications. Biotechnological platforms have the potential to replace traditional plant-based extraction of these compounds with a more sustainable approach. This review first introduced the catalytic characteristics of key enzymes involved in the biosynthetic pathway of crocetin and crocins, including carotenoid cleavage dioxygenases, aldehyde dehydrogenases, and uridine diphosphate glycosyltransferases. Next, we highlighted advanced metabolic engineering strategies aimed at enhancing crocetin and crocin production, such as increasing the pool of precursors and cofactors, protein mining and engineering, tuning protein expression, biosensor, genomic integration, and process optimization. Finally, the paper proposed potential strategies and tools associated with further boosting the heterologous production of crocetin and crocins to meet commercial-scale demands.

Bioengineered yeast for preventing age-related diseases

The aging process entails a multifaceted decline in the capacity to restore homeostasis in response to stress. A prevalent characteristic of many age-related diseases is the presence of low-grade chronic inflammation, a risk factor contributing significantly to morbidity and mortality in the elderly population. Specific lifestyle interventions, such as regular physical activity, targeted diet, and supplementation, can delay the accumulation of chronic age-associated conditions by mitigating inflammation processes. Bioengineered yeast-producing compounds with distinctive bioactivities, including anti-inflammatory properties, have the potential to provide rich dietary alternatives for the prevention of age-related diseases. This review highlights recent achievements in engineering effective yeast platforms, namely Saccharomyces cerevisiae and Yarrowia lipolytica, that hold promise in retarding the onset of aging and age-related ailments.

Microbial Astaxanthin Synthesis by Komagataella phaffii through Metabolic and Fermentation Engineering

Astaxanthin is a kind of carotenoid with a strong antioxidant ability, which has shown broad applications in the areas of healthcare, medicine, cosmetics, food additives, and aquaculture. With the increasing demand for natural products, the microbial production of astaxanthin has become a new hot spot. In this study, the astaxanthin synthesis pathway was first metabolically constructed in Komagataella phaffii (K. phaffii)(Pichia pastoris). By exploring the combination of different promoters, astaxanthin producers were obtained. Then, the key enzymes in the astaxanthin synthesis pathway were explored, and different enzyme assembly strategies and an increase in NADPH supply were used to improve the astaxanthin production. Furthermore, fermentation parameters including temperature, the concentration of the carbon source, nitrogen sources, metal ions, BHT (2,6-di-tert-butyl-4-methylphenol), and Tween-80 were comprehensively investigated for the microbial growth and astaxanthin synthesis. Finally, the astaxanthin production reached 716.13 mg/L by fed-batch fermentation in a 5 L bioreactor, which was the highest production of astaxanthin synthesized by K. phaffii.

De novo biosynthesis of nylon 12 monomer ω-aminododecanoic acid

Nylon 12 is valued for its exceptional properties and diverse industrial applications. Traditional chemical synthesis of nylon 12 faces significant technical challenges and environmental concerns, while bioproduction from plant-extracted decanoic acid (DDA) raises issues related to deforestation and biodiversity loss. Here, we show the development of an engineered Escherichia coli cell factory capable of biosynthesizing the nylon 12 monomer, ω-aminododecanoic acid (ω-AmDDA), from glucose. We enable de novo biosynthesis of ω-AmDDA by introducing a thioesterase specific to C12 acyl-ACP and a multi-enzyme cascade converting DDA to ω-AmDDA. Through modular pathway engineering, redesign and dimerization enhancement of the rate-limiting P450, reconstruction of redox and energy homeostasis, and enhancement of oxidative stress tolerance, we achieve a production level of 471.5 mg/L ω-AmDDA from glucose in shake flasks. This work paves the way for sustainable nylon 12 production and offers insights for bioproduction of other fatty acid-derived products.

Advances in Metabolic Engineering for the Accumulation of Astaxanthin Biosynthesis

Astaxanthin, a lipophilic carotenoid renowned for its strong antioxidant activity, holds significant commercial value across industries such as feed, food, and cosmetics. Although astaxanthin can be synthesized through chemical methods, it may contain toxic by-products in the synthesized astaxanthin, limiting its application in medicine or functional food. Natural astaxanthin can be extracted from algae, however, the cultivation cycle of algae is relatively longer compared to microorganisms. With the advancement of synthetic biology and metabolic engineering, the method of microbial fermentation has emerged as a promising strategy for the large-scale production of astaxanthin. This article provides a comprehensive overview of the research progress in astaxanthin biosynthesis, highlighting the use of the natural host Xanthophyllomyces dendrorhous, and the heterologous hosts Yarrowia lipolytica and Saccharomyces cerevisiae. Additionally, future research prospects are also discussed.

The bioproduction of astaxanthin: A comprehensive review on the microbial synthesis and downstream extraction

Astaxanthin is a valuable orange-red carotenoid with wide applications in agriculture, food, cosmetics, pharmaceuticals and nutraceuticals areas. At present, the biological synthesis of astaxanthin mainly relies on Haematococcus pluvialis and Xanthophyllomyces dendrorhous. With the rapid development of synthetic biology, more recombinant microbial hosts have been genetically constructed for astaxanthin production including Escherichia coli, Saccharomyces cerevisiae and Yarrowia lipolytica. As multiple genes (15) were involved in the astaxanthin synthesis, it is particularly important to adopt different strategies to balance the metabolic flow towards the astaxanthin synthesis. Furthermore, astaxanthin is a fat-soluble compound stored intracellularly, hence efficient extraction methods are also essential for the economical production of astaxanthin. Several efficient and green extraction methods of astaxanthin have been reported in recent years, including the superfluid extraction, ionic liquid extraction and microwave-assisted extraction. Accordingly, this review will comprehensively introduce the advances on the astaxanthin production and extraction by using different microbial hosts and strategies to improve the astaxanthin synthesis and extraction efficiency.

Characterization and engineering of peroxisome targeting sequences for compartmentalization engineering in Pichia pastoris

Peroxisomal compartmentalization has emerged as a highly promising strategy for reconstituting intricate metabolic pathways. In recent years, significant progress has been made in the peroxisomes through harnessing precursor pools, circumventing metabolic crosstalk, and minimizing the cytotoxicity of exogenous pathways. However, it is important to note that in methylotrophic yeasts (e.g. Pichia pastoris), the abundance and protein composition of peroxisomes are highly variable, particularly when peroxisome proliferation is induced by specific carbon sources. The intricate subcellular localization of native proteins, the variability of peroxisomal metabolic pathways, and the lack of systematic characterization of peroxisome targeting signals have limited the applications of peroxisomal compartmentalization in P. pastoris. Accordingly, this study established a high-throughput screening method based on β-carotene biosynthetic pathway to evaluate the targeting efficiency of PTS1s (Peroxisome Targeting Signal Type 1) in P. pastoris. First, 25 putative endogenous PTS1s were characterized and 3 PTS1s with high targeting efficiency were identified. Then, directed evolution of PTS1s was performed by constructing two PTS1 mutant libraries, and a total of 51 PTS1s (29 classical and 22 noncanonical PTS1s) with presumably higher peroxisomal targeting efficiency were identified, part of which were further characterized via confocal microscope. Finally, the newly identified PTS1s were employed for peroxisomal compartmentalization of the geraniol biosynthetic pathway, resulting in more than 30% increase in the titer of monoterpene compared with when the pathway was localized to the cytosol. The present study expands the synthetic biology toolkit and lays a solid foundation for peroxisomal compartmentalization in P. pastoris.

Metabolic Engineering of Saccharomyces cerevisiae for Production of Canthaxanthin, Zeaxanthin, and Astaxanthin

The sustainable production of natural compounds is increasingly important in today's industrial landscape. This study investigates the metabolic engineering of Saccharomyces cerevisiae for the efficient biosynthesis of valuable carotenoids: canthaxanthin, zeaxanthin, and astaxanthin. Utilizing a tailored parental yeast strain, Sp_Bc, we optimized the carotenoid pathway by screening and identifying CrtW and CrtZ enzymatic variants. The CrtW variant from Bradyrhizobium sp. achieved a canthaxanthin titer of 425.1 ± 69.1 µg/L, while the CrtZ variant from Pantoea ananatis achieved a zeaxanthin titer of 70.5 ± 10.8 µg/L. Additionally, we optimized carotenoid production by exploring enzyme fusion strategies for all three studied carotenoids and organelle compartmentalization specifically for enhancing astaxanthin synthesis. We further improved carotenoid production by integrating the optimal gene constructs into the yeast genome and deleting the GAL80 gene, enabling the use of sucrose as a carbon source. The engineered strain Sp_Bc-Can001 ∆gal80 was evaluated in a 5 L bioreactor fermentation, achieving a notable canthaxanthin titer of 60.36 ± 1.51 mg/L using sucrose. This research conclusively establishes S. cerevisiae as a viable platform for efficient carotenoid biosynthesis and, for the first time in this yeast system, illustrates sucrose's viability as a carbon source for canthaxanthin production. These findings pave the way for sustainable, cost-effective carotenoid production at an industrial scale.

Building Synthetic Yeast Factories to Produce Fat-soluble Antioxidants

Fat-soluble antioxidants play a vital role in protecting the body against oxidative stress and damage. The rapid advancements in metabolic engineering and synthetic biology have offered a promising avenue for economically producing fat-soluble antioxidants by engineering microbial chassis. This review provides an overview of the recent progress in engineering yeast microbial factories to produce three main groups of lipophilic antioxidants: carotenoids, vitamin E, and stilbenoids. In addition to discussing the classic strategies employed to improve precursor availability and alleviate carbon flux competition, this review delves deeper into the innovative approaches focusing on enzyme engineering, product sequestration, subcellular compartmentalization, multistage fermentation, and morphology engineering. We conclude the review by highlighting the prospects of microbial engineering for lipophilic antioxidant production.

Advances in the metabolic engineering of Saccharomyces cerevisiae and Yarrowia lipolytica for the production of -carotene

β-Carotene is one kind of the most important carotenoids. The major functions of β-carotene include the antioxidant and anti-cardiovascular properties, which make it a growing market. Recently, the use of metabolic engineering to construct microbial cell factories to synthesize β-carotene has become the latest model for its industrial production. Among these cell factories, yeasts including Saccharomyces cerevisiae and Yarrowia lipolytica have attracted the most attention because of the: security, mature genetic manipulation tools, high flux toward carotenoids using the native mevalonate pathway and robustness for large-scale fermentation. In this review, the latest strategies for β-carotene biosynthesis, including protein engineering, promoters engineering and morphological engineering are summarized in detail. Finally, perspectives for future engineering approaches are proposed to improve β-carotene production.

Reactive oxygen species derived from NADPH oxidase as signaling molecules regulate fatty acids and astaxanthin accumulation in Chromochloris zofingiensis

Abiotic stresses can increase the total fatty acid (TFA) and astaxanthin accumulation in microalgae. However, it remains unknown whether a unified signal transduction mechanism exists under different stresses. This study explored the link between nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-derived reactive oxygen species (ROS) and the accumulation of fatty acids and astaxanthin in Chromochloris zofingiensis under three abiotic stresses. Results showed significant increases in fatty acid, astaxanthin, and ROS levels under nitrogen deficiency, phosphorus deficiency, and high-salinity stress. The introduction of the NADPH oxidase inhibitor diphenyleneiodonium (DPI) decreased the content of these components. This underscores the pivotal role of NADPH oxidase-derived ROS in the accumulation of fatty acid and astaxanthin under abiotic stress. Analysis of transcriptomes across three conditions following DPI addition revealed 1,445 shared differentially expressed genes (DEGs). Enrichment analysis revealed that biotin, betalain, thiamine, and glucosinolate may be important in stress responses. The heatmap demonstrated that DPI notably suppressed gene expression in the fatty acid and carotenoid biosynthesis pathways. Our findings underscore the pivotal role of NADPH oxidase-derived ROS in the accumulation of fatty acid and astaxanthin under abiotic stresses.

Transcription Factor Pdr3p Promotes Carotenoid Biosynthesis by Activating GAL Promoters in Saccharomyces cerevisiae

Pleiotropic drug resistance (PDR) family proteins have been extensively studied for their roles in transporting hydrophobic substances, including carotenoids. Overexpression of the PDR family regulator Pdr3p was recently found to boost the biosynthesis of carotenoids, which could not be explained by enhanced product secretion due to the meager extracellular proportions. To provide insights into the possible mechanism, comparative transcriptomics, reverse metabolic engineering, and electrophoretic mobility shift assay (EMSA) were conducted. Transcriptomic data suggested an unexpected correlation between Pdr3p overexpression and the transcriptional levels of GAL promoter-driven genes. This assumption was verified using mCherry and the lycopene synthetic pathway as the reporters. qRT-PCR and EMSA provided further evidence for the activation of GAL promoters by Pdr3p binding to their upstream activation sequences (UASs). This work gives insight into the mechanism of Pdr3p-promoted carotenoid production and highlights the complicated metabolic networking between transcriptional factors and promoters in yeast.

Combinatorial metabolic engineering of Saccharomyces cerevisiae for improved production of 7-dehydrocholesterol

7-Dehydrocholesterol (7-DHC), a key pharmaceutical intermediate in the production of vitamin D3, has a wide range of applications. To explore fermentative synthesis of 7-DHC, a 7-DHC-producing Saccharomyces cerevisiae strain was constructed by blocking the competitive pathway, eliminating rate-limiting steps, altering global regulation, and pathway compartmentalization. After blocking the competitive pathway by disrupting ERG5 and ERG6 and introducing DHCR24 from Gallus gallus, S. cerevisiae produced 139.72 mg/L (17.04 mg/g dry cell weight, hereafter abbreviated as DCW) 7-DHC. Subsequent alteration of global regulation by deleting ROX1 and overexpressing UPC2-1 increased 7-DHC production to 217.68 mg/L (37.56 mg/g DCW). To remove the accumulated squalene, the post-squalene pathway was strengthened by co-overexpression of P GAL1 -driven ERG11 and P GAL10 -driven ERG1, which improved 7-DHC titer and yield to 281.73 mg/L and 46.78 mg/g DCW, respectively, and reduced squalene content by 90.12%. We surmised that the sterol precursors in the plasma membrane and peroxisomes may not be accessible to the pathway enzymes, thus we re-localized DHCR24p and Erg2p-GGGGS-Erg3p to the plasma membrane and peroxisomes, boosting 7-DHC production to 357.53 mg/L (63.12 mg/g DCW). Iron supplementation further increased 7-DHC production to 370.68 mg/L in shake flasks and 1.56 g/L in fed-batch fermentation. This study demonstrates the power of global regulation and subcellular relocalization of key enzymes to improve 7-DHC synthesis in yeast.

Advances in the dynamic control of metabolic pathways in Saccharomyces cerevisiae

The metabolic engineering of Saccharomyces cerevisiae has great potential for enhancing the production of high-value chemicals and recombinant proteins. Recent studies have demonstrated the effectiveness of dynamic regulation as a strategy for optimizing metabolic flux and improving production efficiency. In this review, we provide an overview of recent advancements in the dynamic regulation of S. cerevisiae metabolism. Here, we focused on the successful utilization of transcription factor (TF)-based biosensors within the dynamic regulatory network of S. cerevisiae. These biosensors are responsive to a wide range of endogenous and exogenous signals, including chemical inducers, light, temperature, cell density, intracellular metabolites, and stress. Additionally, we explored the potential of omics tools for the discovery of novel responsive promoters and their roles in fine-tuning metabolic networks. We also provide an outlook on the development trends in this field.

Industrially Important Fungal Carotenoids: Advancements in Biotechnological Production and Extraction

Carotenoids are lipid-soluble compounds that are present in nature, including plants and microorganisms such as fungi, certain bacteria, and algae. In fungi, they are widely present in almost all taxonomic classifications. Fungal carotenoids have gained special attention due to their biochemistry and the genetics of their synthetic pathway. The antioxidant potential of carotenoids may help fungi survive longer in their natural environment. Carotenoids may be produced in greater quantities using biotechnological methods than by chemical synthesis or plant extraction. The initial focus of this review is on industrially important carotenoids in the most advanced fungal and yeast strains, with a brief description of their taxonomic classification. Biotechnology has long been regarded as the most suitable alternative way of producing natural pigment from microbes due to their immense capacity to accumulate these pigments. So, this review mainly presents the recent progress in the genetic modification of native and non-native producers to modify the carotenoid biosynthetic pathway for enhanced carotenoid production, as well as factors affecting carotenoid biosynthesis in fungal strains and yeast, and proposes various extraction methods to obtain high yields of carotenoids in an attempt to find suitable greener extraction methods. Finally, a brief description of the challenges regarding the commercialization of these fungal carotenoids and the solution is also given.

Metabolic Engineering of Model Microorganisms for the Production of Xanthophyll

Xanthophyll is an oxidated version of carotenoid. It presents significant value to the pharmaceutical, food, and cosmetic industries due to its specific antioxidant activity and variety of colors. Chemical processing and conventional extraction from natural organisms are still the main sources of xanthophyll. However, the current industrial production model can no longer meet the demand for human health care, reducing petrochemical energy consumption and green sustainable development. With the swift development of genetic metabolic engineering, xanthophyll synthesis by the metabolic engineering of model microorganisms shows great application potential. At present, compared to carotenes such as lycopene and β-carotene, xanthophyll has a relatively low production in engineering microorganisms due to its stronger inherent antioxidation, relatively high polarity, and longer metabolic pathway. This review comprehensively summarized the progress in xanthophyll synthesis by the metabolic engineering of model microorganisms, described strategies to improve xanthophyll production in detail, and proposed the current challenges and future efforts needed to build commercialized xanthophyll-producing microorganisms.

Metabolic Engineering of Yarrowia lipolytica for Terpenoid Production: Tools and Strategies

Terpenoids are a diverse group of compounds with isoprene units as basic building blocks. They are widely used in the food, feed, pharmaceutical, and cosmetic industries due to their diverse biological functions such as antioxidant, anticancer, and immune enhancement. With an increase in understanding the biosynthetic pathways of terpenoids and advances in synthetic biology techniques, microbial cell factories have been built for the heterologous production of terpenoids, with the oleaginous yeast Yarrowia lipolytica emerging as an outstanding chassis. In this paper, recent progress in the development of Y. lipolytica cell factories for terpenoid production with a focus on the advances in novel synbio tools and metabolic engineering strategies toward enhanced terpenoid biosynthesis is reviewed.

Highly Active Astaxanthin Production from Waste Molasses by Mutated Rhodosporidium toruloides G17

Astaxanthin is increasingly attracting commercial interest for its application in the nutraceutical and pharmaceutical industries. This study aimed to produce astaxanthin from molasses with our newly mutated strain of Rhodosporidium toruloides G17 and to evaluate biological activities of the produced astaxanthin. To maximize the astaxanthin yield, the response surface methodology was used so as to optimize the culture conditions. A maximum astaxanthin yield of 1262.08 ± 14.58 µg/L was achieved by growing R. toruloides G17 in a molasses-based medium containing 49.39 g/L reducing sugar, 1.00 g/L urea, 4.15 g/L MgSO4·7H2O, and 10.05% inoculum ratio. The produced astaxanthin was then purified and studied for its antioxidant and anticancer activities. This compound exhibited 123-fold higher antioxidant activity than α-tocopherol, with an IC50 value of 0.97 ± 0.01 µg/mL. The astaxanthin also showed a potent inhibitory ability against the following three cancer cell lines: HeLa, A549, and MCF7, with IC50 values of 69.07 ± 2.4 µg/mL, 55.60 ± 2.64 µg/mL, and 56.38 ± 4.1 µg/mL, respectively. This study indicates that astaxanthin derived from our newly mutated R. toruloides G17 is a promising anticancer and antioxidant agent for further pharmaceutical applications.

Red yeasts and their carotenogenic enzymes for microbial carotenoid production

Carotenoids are C40 isoprene-based compounds with significant commercial interests that harbor diverse bioactivities. Prominent examples of carotenoids are beta-carotene, a precursor to vitamin A essential for proper eye health, and lycopene and astaxanthin, powerful antioxidants implicated in preventing cancers and atherosclerosis. Due to their benefits to human health, the market value for carotenoids is rapidly increasing and is projected to reach USD 1.7 billion by 2025. However, their production now relies on chemical synthesis and extraction from plants that pose risks to food management and numerous biological safety issues. Thus, carotenoid production from microbes is considered a promising strategy for achieving a healthy society with more sustainability. Red yeast is a heterogeneous group of basidiomycetous fungi capable of producing carotenoids. It is a critical source of microbial carotenoids from low-cost substrates. Carotenogenic enzymes from red yeasts have also been highly efficient, invaluable biological resources for biotechnological applications. In this minireview, we focus on red yeast as a promising source for microbial carotenoids, strain engineering strategies for improving carotenoid production in red yeasts, and potential applications of carotenogenic enzymes from red yeasts in conventional and nonconventional yeasts.

Integrated pathway engineering and transcriptome analysis for improved astaxanthin biosynthesis in Yarrowia lipolytica

Astaxanthin is a high value carotenoid with a broad range of commercial applications due to its superior antioxidant properties. In this study, β-carotene-producing Yarrowia lipolytica XK17 constructed in the lab was employed for astaxanthin biosynthesis. The catalytic effects of β-carotene ketolase CrtW and β-carotene hydroxylase CrtZ from various species were investigated. The PspCrtW from Paracoccus sp. and HpCrtZ# from Haematococcus pluvialis were confirmed to be the best combination in converting β-carotene. Several key bottlenecks in biomass and astaxanthin biosynthesis were effectively eliminated by optimizing the expression of the above enzymes and restoring uracil/leucine biosynthesis. In addition, the effects of astaxanthin biosynthesis on cell metabolism were investigated by integrated analysis of pathway modification and transcriptome information. After further optimization, strain DN30 was able to synthesize up to 730.3 mg/L astaxanthin in laboratory 5-L fermenter. This study provides a good metabolic strategy and a sustainable development platform for high-value carotenoid production.

Functional diversity and metabolic engineering of plant-specialized metabolites

Plants are talented biochemists that produce a broad diversity of small molecules. These so-called specialized metabolites (SMs) play critical roles in the adaptive evolution of plants to defend against biotic and abiotic stresses, attract pollinators, and modulate soil microbiota for their own benefits. Many plant SMs have been used as nutrition and flavor compounds in our daily food, as well as drugs for treatment of human diseases. Current multi-omics tools have significantly accelerated the process of biosynthetic pathway elucidation in plants through correlation analyses, genetic mapping, and de novo biosynthetic gene cluster predictions. Understanding the biosynthesis of plant SMs has enabled reconstitution of naturally occurring specialized metabolic pathways in microbial hosts, providing a sustainable supply of these high-value molecules. In this review, we illustrate the general functions of several typical plant SMs in natural ecosystems and for human societies. We then provide an overview of current methods elucidating the biosynthetic pathways of plant SMs, and synthetic biology strategies that optimize the efficiency of heterologous biosynthetic pathways in microbial hosts. Moving forward, dissection of the functions and application of plant SMs by using current multidiscipline approaches would be greatly benefit to the scientific community and human societies.

Advances in the synthesis of three typical tetraterpenoids including β-carotene, lycopene and astaxanthin

Carotenoids are natural pigments that widely exist in nature. Due to their excellent antioxidant, anticancer and anti-inflammatory properties, carotenoids are commonly used in food, medicine, cosmetic and other fields. At present, natural carotenoids are mainly extracted from plants, algae and microorganisms. With the rapid development of metabolic engineering and molecular biology as well as the continuous in-depth study of carotenoids synthesis pathways, industrial microorganisms have showed promising applications in the synthesis of carotenoids. In this review, we introduced the properties of several carotenoids and their biosynthetic metabolism process. Then, the microorganisms synthesizing carotenoids through the natural and non-natural pathways and the extraction methods of carotenoids were summarized and compared. Meanwhile, the influence of substrates on the carotenoids production was also listed. The methods and strategies for achieving high carotenoid production are categorized to help with future research.

Advances in Metabolic Engineering Paving the Way for the Efficient Biosynthesis of Terpenes in Yeasts

Terpenes are a large class of secondary metabolites with diverse structures and functions that are commonly used as valuable raw materials in food, cosmetics, and medicine. With the development of metabolic engineering and emerging synthetic biology tools, these important terpene compounds can be sustainably produced using different microbial chassis. Currently, yeasts such as Saccharomyces cerevisiae and Yarrowia lipolytica have received extensive attention as potential hosts for the production of terpenes due to their clear genetic background and endogenous mevalonate pathway. In this review, we summarize the natural terpene biosynthesis pathways and various engineering strategies, including enzyme engineering, pathway engineering, and cellular engineering, to further improve the terpene productivity and strain stability in these two widely used yeasts. In addition, the future prospects of yeast-based terpene production are discussed in light of the current progress, challenges, and trends in this field. Finally, guidelines for future studies are also emphasized.

Spatiotemporal Regulation of Astaxanthin Synthesis in S. cerevisiae

As a high-valued antioxidant, astaxanthin biosynthesis using microbial cell factories has attracted increasing attention. However, its lipophilic nature conflicts with the limited storage capacity for lipophilic substances of model microorganisms such as Saccharomyces cerevisiae. Expansion of lipid droplets by enhancing lipid synthesis provides more storage room while diverting the metabolic flux from the target pathway. Therefore, proper spatial regulation is required. In this study, a library of genes related to lipid metabolism were screened using the trifunctional CRISPR system, identifying opi3 and hrd1 as new engineering targets to promote astaxanthin synthesis by moderately rather than excessively upregulating lipid synthesis. The astaxanthin yield reached 9.79 mg/g DCW after lipid engineering and was further improved to 10.21 mg/g DCW by balancing the expression of β-carotene hydroxylase and ketolase. Finally, by combining spatial regulation through lipid droplet engineering and temporal regulation via temperature-responsive pathway expression, 446.4 mg/L astaxanthin was produced in fed-batch fermentation.

Sustainable production of astaxanthin in microorganisms: the past, present, and future

Astaxanthin (3,3'-dihydroxy-4,4'-diketo-β-carotene) is a type of C40 carotenoid with remarkable antioxidant characteristics, showing significant application prospects in many fields. Traditionally, the astaxanthin is mainly obtained from chemical synthesis and natural acquisition, with both approaches having many limitations and not capable of meeting the growing market demand. In order to cope with these challenges, novel techniques, e.g., the innovative cell engineering strategies, have been developed to increase the astaxanthin production. In this review, we first elaborated the biosynthetic pathway of astaxanthin, with the key enzymes and their functions discussed in the metabolic process. Then, we summarized the conventional, non-genetic strategies to promote the production of astaxanthin, including the methods of exogenous additives, mutagenesis, and adaptive evolution. Lastly, we reviewed comprehensively the latest studies on the synthesis of astaxanthin in various recombinant microorganisms based on the concept of microbial cell factory. Furthermore, we have proposed several novel technologies for improving the astaxanthin accumulation in several model species of microorganisms.

Optimization of microbial cell factories for astaxanthin production: Biosynthesis and regulations, engineering strategies and fermentation optimization strategies

The global market demand for natural astaxanthin is rapidly increasing owing to its safety, the potential health benefits, and the diverse applications in food and pharmaceutical industries. The major native producers of natural astaxanthin on industrial scale are the alga Haematococcus pluvialis and the yeast Xanthopyllomyces dendrorhous. However, the natural production via these native producers is facing challenges of limited yield and high cost of cultivation and extraction. Alternatively, astaxanthin production via metabolically engineered non-native microbial cell factories such as Escherichia coli, Saccharomyces cerevisiae and Yarrowia lipolytica is another promising strategy to overcome these limitations. In this review we summarize the recent scientific and biotechnological progresses on astaxanthin biosynthetic pathways, transcriptional regulations, the interrelation with lipid metabolism, engineering strategies as well as fermentation process control in major native and non-native astaxanthin producers. These progresses illuminate the prospects of producing astaxanthin by microbial cell factories on industrial scale.

Accumulation and conversion of β-carotene and astaxanthin induced by abiotic stresses in Schizochytrium sp

Astaxanthin is a kind of ketone carotenoid belonging to tetraterpenoids with an excellent antioxidant activity and it is widely used in nutrition and health-care industries. This study aimed to explore the effect of different abiotic stresses on carotenoid production in Schizochytrium sp. Firstly, the characteristics of carotenoid accumulation were studied in Schizochytrium sp. by monitoring the change of carotenoid yields and gene expressions. Then, different abiotic stresses were systematically studied to regulate the carotenoid accumulation. Results showed that low temperature could advance the astaxanthin accumulation, while ferric ion could stimulate the conversion from carotene to astaxanthin. The glucose and monosodium glutamate ratio of 100:5 was helpful for the accumulation of β-carotene. In addition, micro-oxygen supply conditions could increase the yield of β-carotene and astaxanthin by 25.47% and 14.92%, respectively. This study provided the potential regulation strategies for carotenoid production which might be used in different carotenoid-producing strains.

Recent advances in construction and regulation of yeast cell factories

The past decade has witnessed the rapid progress in development of synthetic biology, and advances in construction of yeast cell factories open vast opportunities for green and sustainable production of chemicals. Focusing on the progress in yeast engineering for production of plant natural products in the last 5 years, this review introduces different yeast chassis used for cell factory construction, including Saccharomyces cerevisiae, Yarrowia lipolytica and Komagataella phaffii, together with the emerging genome editing tools. The metabolic regulation strategies developed for yeast engineering are highlighted, such as subcellular pathway localization dynamic regulation, and transporter engineering. C1-based chemical bioproduction by engineered yeast is also covered. Finally, the existing challenges and future prospects in creating efficient yeast cell factories are summarized.

Adaptive laboratory evolution and shuffling of Escherichia coli to enhance its tolerance and production of astaxanthin

Background

Astaxanthin is one of the strongest antioxidants in nature and has been widely used in aquaculture, food, cosmetic and pharmaceutical industries. Numerous stresses caused in the process of a large scale-culture, such as high acetate concentration, high osmolarity, high level of reactive oxygen species, high glucose concentration and acid environment, etc., limit cell growth to reach the real high cell density, thereby affecting astaxanthin production.

Results

We developed an adaptive laboratory evolution (ALE) strategy to enhance the production of chemicals by improving strain tolerance against industrial fermentation conditions. This ALE strategy resulted in 18.5% and 53.7% increases in cell growth and astaxanthin production in fed-batch fermentation, respectively. Whole-genome resequencing showed that 65 mutations with amino acid substitution were identified in 61 genes of the shuffled strain Escherichia coli AST-4AS. CRISPR interference (CRISPRi) and activation (CRISPRa) revealed that the shuffled strain with higher astaxanthin production may be associated with the mutations of some stress response protein genes, some fatty acid biosynthetic genes and rppH. Repression of yadC, ygfI and rcsC, activation of rnb, envZ and recC further improved the production of astaxanthin in the shuffled strain E. coli AST-4AS. Simultaneous deletion of yadC and overexpression of rnb increased the production of astaxanthin by 32% in the shuffled strain E. coli AST-4AS.

Conclusion

This ALE strategy will be powerful in engineering microorganisms for the high-level production of chemicals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13068-022-02118-w.

Biotechnological advances for improving natural pigment production: a state-of-the-art review

In current years, natural pigments are facing a fast-growing global market due to the increase of people's awareness of health and the discovery of novel pharmacological effects of various natural pigments, e.g., carotenoids, flavonoids, and curcuminoids. However, the traditional production approaches are source-dependent and generally subject to the low contents of target pigment compounds. In order to scale-up industrial production, many efforts have been devoted to increasing pigment production from natural producers, via development of both in vitro plant cell/tissue culture systems, as well as optimization of microbial cultivation approaches. Moreover, synthetic biology has opened the door for heterologous biosynthesis of pigments via design and re-construction of novel biological modules as well as biological systems in bio-platforms. In this review, the innovative methods and strategies for optimization and engineering of both native and heterologous producers of natural pigments are comprehensively summarized. Current progress in the production of several representative high-value natural pigments is also presented; and the remaining challenges and future perspectives are discussed.

Construction of Canthaxanthin-Producing Yeast by Combining Spatiotemporal Regulation and Pleiotropic Drug Resistance Engineering

The ketocarotenoid canthaxanthin has important applications in the feed industry. Its biosynthesis using microbial cell factories is an attractive alternative to the current chemical synthesis route. Canthaxanthin-producing Saccharomyces cerevisiae was constructed by introducing the β-carotene ketolase variant OBKTM29 into a β-carotene producer. Subcellular re-localization of OBKTM29 was explored, together with copy number adjustment both in the cytoplasm and on the periplasmic membrane, to accelerate the conversion of β-carotene to canthaxanthin. Moreover, pleiotropic drug resistance (PDR) regulators Pdr1 and Pdr3 were overexpressed to improve the stress tolerance of the yeast strain, leading to obviously enhanced canthaxanthin production. The synthetic pathway was then regulated by a temperature-responsive GAL system to separate product synthesis from cell growth. Finally, 1.44 g/L canthaxanthin was harvested in fed-batch fermentation. This work demonstrated the power of spatial and temporal regulation and the efficiency of PDR engineering in heterologous biosynthesis.

Anti-inflammatory action of astaxanthin and its use in the treatment of various diseases

Astaxanthin (AST) is a red pigmented carotenoid with significant antioxidant, anti-inflammatory, anti-proliferative, and anti-apoptotic properties. In this study, we summarize the available literature on the anti-inflammatory efficacy of AST in various chronic and acute disorders, such as neurodegenerative, renal-, hepato-, skin- and eye-related diseases, as well as gastrointestinal disorders. In addition, we elaborated on therapeutic efficacy of AST and the role of several pathways, including PI3K/AKT, Nrf2, NF-κB, ERK1/2, JNK, p38 MAPK, and JAK-2/STAT-3 in mediating its effects. However, additional experimental and clinical studies should be performed to corroborate the anti-inflammatory effects and protective effects of AST against inflammatory diseases in humans. Nevertheless, this review suggests that AST with its demonstrated anti-inflammatory property may be a suitable candidate for drug design with novel technology.

"Light modulates transcriptomic dynamics upregulating astaxanthin accumulation in Haematococcus: A review"

Haematococcus pluvialis is a green alga that can accumulate high astaxanthin content, a commercially demanding market keto food. Due to its high predicted market value of about 3.4 billion USD in 2027, it is essential to increase its production. Therefore, it is crucial to understand the genetic mechanism and gene expressions profile during astaxanthin synthesis. The effect of poly- and mono-chromatic light of different wavelengths and different intensities have shown to influence the gene expression towards astaxanthin production. This includes transcriptomic gene analysis in H. pluvialis underneath different levels of illumination stress. This review has placed the most recent data on the effects of light on bioastaxanthin production in the context of previous studies, which were more focused on the biochemical and physiological sides. Doing so, it contributes to delineate new ways along the biotechnological process with the aim to increase bioastaxanthin production while decreasing production costs.

Targeting pathway expression to subcellular organelles improves astaxanthin synthesis in Yarrowia lipolytica

Metabolic engineering approaches for the production of high-value chemicals in microorganisms mostly use the cytosol as general reaction vessel. However, sequestration of enzymes and substrates, and metabolic cross-talk frequently prevent efficient synthesis of target compounds in the cytosol. Organelle compartmentalization in eukaryotic cells suggests ways for overcoming these challenges. Here we have explored this strategy by expressing the astaxanthin biosynthesis pathway in sub-organelles of the oleaginous yeast Yarrowia lipolytica. We first showed that fusion of the two enzymes converting β-carotene to astaxanthin, β-carotene ketolase and hydroxylase, performs better than the expression of individual enzymes. We next evaluated the pathway when expressed in compartments of lipid body, endoplasmic reticulum or peroxisome, individually and in combination. Targeting the astaxanthin pathway to subcellular organelles not only accelerated the conversion of β-carotene to astaxanthin, but also significantly decreased accumulation of the ketocarotenoid intermediates. Anchoring enzymes simultaneously to all three organelles yielded the largest increase of astaxanthin synthesis, and ultimately produced 858 mg/L of astaxanthin in fed-batch fermentation (a 141-fold improvement over the initial strain). Our study is expected to help unlock the full potential of subcellular compartments and advance LB-based compartmentalized isoprenoid biosynthesis in Y. lipolytica.

Carotenoids from fungi and microalgae: A review on their recent production, extraction, and developments

The demand for carotenoids from natural sources obtained by biological extraction methods is increasing with the development of biotechnology and the continued awareness of food safety. Natural plant-derived carotenoids have a relatively high production cost and are affected by the season, while microbial-derived carotenoids are favored due to their natural, high-efficiency, low production cost, and ease of industrialization. This article reviewed the following aspects of natural carotenoids derived from microorganisms: (1) the structures and properties of main carotenoids; (2) fungal and microalgal sources of the main carotenoids; (3) influencing factors and modes of improvement for carotenoids production; (4) efficient extraction methods for carotenoids; and (5) the commercial value of carotenoids. This review provided a reference and guidance for the development of natural carotenoids derived from microorganisms.

Engineering Plant Sesquiterpene Synthesis into Yeasts: A Review

Sesquiterpenes are natural compounds composed of three isoprene units. They represent the largest class of terpene compounds found in plants, and many have remarkable biological activities. Furthermore, sesquiterpenes have broad applications in the flavor, pharmaceutical and biofuel industries due to their complex structures. With the development of metabolic engineering and synthetic biology, the production of different sesquiterpenes has been realized in various chassis microbes. The microbial production of sesquiterpenes provides a promising alternative to plant extraction and chemical synthesis, enabling us to meet the increasing market demand. In this review, we summarized the heterologous production of different plant sesquiterpenes using the eukaryotic yeasts Saccharomyces cerevisiae and Yarrowia lipolytica, followed by a discussion of common metabolic engineering strategies used in this field.

Metabolic engineering of Saccharomyces cerevisiae for enhanced production of caffeic acid

As a natural phenolic acid product of plant source, caffeic acid displays diverse biological activities and acts as an important precursor for the synthesis of other valuable compounds. Limitations in chemical synthesis or plant extraction of caffeic acid trigger interest in its microbial biosynthesis. Recently, Saccharomyces cerevisiae has been reported for the biosynthesis of caffeic acid via episomal plasmid-mediated expression of pathway genes. However, the production was far from satisfactory and even relied on the addition of precursor. In this study, we first established a controllable and stable caffeic acid pathway by employing a modified GAL regulatory system to control the genome-integrated pathway genes in S. cerevisiae and realized biosynthesis of 222.7 mg/L caffeic acid. Combinatorial engineering strategies including eliminating the tyrosine-induced feedback inhibition, deleting genes involved in competing pathways, and overexpressing rate-limiting enzymes led to about 2.6-fold improvement in the caffeic acid production, reaching up to 569.0 mg/L in shake-flask cultures. To our knowledge, this is the highest ever reported titer of caffeic acid synthesized by engineered yeast. This work showed the prospect for microbial biosynthesis of caffeic acid and laid the foundation for constructing biosynthetic pathways of its derived metabolites. KEY POINTS: Genomic integration of ORgTAL, OHpaB, and HpaC for caffeic acid production in yeast. Feedback inhibition elimination and Aro10 deletion improved caffeic acid production. The highest ever reported titer (569.0 mg/L) of caffeic acid synthesized by yeast.

Recent advances in biotechnology for marine enzymes and molecules

The marine environment is the most biologically and chemically diverse habitat on Earth, and provides numerous marine-derived products, including enzymes and molecules, for industrial and pharmaceutical applications. Marine biotechnology provides important biological resources from marine habitat conservation to applied science. In recent years, advances in techniques in interdisciplinary research fields, including metabolic engineering and synthetic biology have significantly improved the production of marine-derived commodities. In this review, we outline the recent progress in the use or marine enzymes and molecules in biotechnology, including newly discovered products, function optimization of enzymes, and production improvement of small molecules.

Heterologous biosynthesis of lutein in S. cerevisiae enabled by temporospatial pathway control

The market-expanding lutein is currently mainly supplied by plant extraction, with microbial fermentation using engineered cell factory emerging as a promising substitution. During construction of lutein-producing yeast, α-carotene formation through asymmetric ε- and β-cyclization of lycopene was found as the main limiting step, attributed to intra-pathway competition of the cyclases for lycopene, forming β-carotene instead. To solve this problem, temperature-responsive expression of β-cyclase was coupled to constitutive expression of ε-cyclase for flux redirection to α-carotene by allowing ε-cyclization to occur first. Meanwhile, the ε-cyclase was engineered and re-localized to the plasma membrane for further flux reinforcement towards α-carotene. Finally, pathway extension with proper combination of carotenoid hydroxylases enabled lutein (438 μg/g dry cells) biosynthesis in S. cerevisiae. The success of heterologous lutein biosynthesis in yeast suggested temporospatial pathway control as a potential strategy in solving intra-pathway competitions, and may also be applicable for promoting the biosynthesis of other natural products.

Reprogramming microorganisms for the biosynthesis of astaxanthin via metabolic engineering

There is an increasing demand for astaxanthin in food, feed, cosmetics and pharmaceutical applications because of its superior anti-oxidative and coloring properties. However, naturally produced astaxanthin is expensive, mainly due to low productivity and limited sources. Reprogramming of microorganisms for astaxanthin production via metabolic engineering is a promising strategy. We primarily focus on the application of synthetic biology, enzyme engineering and metabolic engineering in enhancing the synthesis and accumulation of astaxanthin in microorganisms in this review. We also discuss the biosynthetic pathways of astaxanthin within natural producers, and summarize the achievements and challenges in reprogramming microorganisms for enhancing astaxanthin production. This review illuminates recent biotechnological advances in microbial production of astaxanthin. Future perspectives on utilization of new technologies for boosting microbial astaxanthin production are also discussed.

Coordinated Expression of Astaxanthin Biosynthesis Genes for Improved Astaxanthin Production in Escherichia coli

Astaxanthin has great potential commercial value in the feed, cosmetics, and nutraceutical industries due to its strong antioxidant capacity. In this study, the Escherichia coli strain CAR026 with completely balanced metabolic flow was selected as the starting strain for the production of astaxanthin. The expression of β-carotene ketolase (CrtW) and β-carotene hydroxylase (CrtZ), which catalyze the conversion of β-carotene to astaxanthin, was coordinated, and a bottleneck was eliminated by increasing the copy number of crtY in CAR026. The resulting strain Ast007 produced 21.36 mg/L and 4.6 mg/g DCW of astaxanthin in shake flasks. In addition, the molecular chaperone genes groES-groEL were regulated to further improve the astaxanthin yield. The best strain Gro-46 produced 26 mg/L astaxanthin with a yield of 6.17 mg/g DCW in shake flasks and 1.18 g/L astaxanthin after 60 h of fermentation under fed-batch conditions. To the best of our knowledge, this is the highest astaxanthin obtained using engineered E. coli to date.

Astaxanthin and its Effects in Inflammatory Responses and Inflammation-Associated Diseases: Recent Advances and Future Directions

Astaxanthin is a natural lipid-soluble and red-orange carotenoid. Due to its strong antioxidant property, anti-inflammatory, anti-apoptotic, and immune modulation, astaxanthin has gained growing interest as a multi-target pharmacological agent against various diseases. In the current review, the anti-inflammation mechanisms of astaxanthin involved in targeting for inflammatory biomarkers and multiple signaling pathways, including PI3K/AKT, Nrf2, NF-κB, ERK1/2, JNK, p38 MAPK, and JAK-2/STAT-3, have been described. Furthermore, the applications of anti-inflammatory effects of astaxanthin in neurological diseases, diabetes, gastrointestinal diseases, hepatic and renal diseases, eye and skin disorders, are highlighted. In addition to the protective effects of astaxanthin in various chronic and acute diseases, we also summarize recent advances for the inconsistent roles of astaxanthin in infectious diseases, and give our view that the exact function of astaxanthin in response to different pathogen infection and the potential protective effects of astaxanthin in viral infectious diseases should be important research directions in the future.

Fermentative production of Vitamin E tocotrienols in Saccharomyces cerevisiae under cold-shock-triggered temperature control

The diverse physiological functions of tocotrienols have listed them as valuable supplementations to α-tocopherol-dominated Vitamin E products. To make tocotrienols more readily available, tocotrienols-producing S. cerevisiae has been constructed by combining the heterologous genes from photosynthetic organisms with the endogenous shikimate pathway and mevalonate pathway. After identification and elimination of metabolic bottlenecks and enhancement of precursors supply, the engineered yeast can produce tocotrienols at yield of up to 7.6 mg/g dry cell weight (DCW). In particular, proper truncation of the N-terminal transit peptide from the plant-sourced enzymes is crucial. To further solve the conflict between cell growth and tocotrienols accumulation so as to enable high-density fermentation, a cold-shock-triggered temperature control system is designed for efficient control of two-stage fermentation, leading to production of 320 mg/L tocotrienols. The success in high-density fermentation of tocotrienols by engineered yeast sheds light on the potential of fermentative production of vitamin E tocochromanols.

Tocotrienols are valuable supplementations to α-tocopherol-dominated Vitamin E products. Here, the authors engineer baker’s yeast by combining the heterologous genes from photosynthetic organisms with the endogenous pathway for the production of tocotrienols under cold-shock-triggered temperature control.