Aug 2026· World Journal of Microbiology & Biotechnology· Vol 42· 0 citations· 41 references
Medicine
TL;DR
This study demonstrates the combined optimization of isozyme combination and environmental stress to elevate the synthesis of astaxanthin and other carotenoids in D. salina, providing new research ideas and experimental evidence for the future construction of high-yield engineered algal strains.
Astaxanthin is a keto-carotenoid with high added value. In this study, we aimed to biosynthesize 3S,3′S-astaxanthin efficiently and sustainably from the renewable single-carbon (C1) feedstock methanol through multiplex metabolic engineering strategies in Komagataella phaffii. First, the K. phaffii cell-free terpene synthesis system was established successfully and applied to evaluate the astaxanthin synthase combinations rapidly. We then systematically engineered K. phaffii for the overproduction of 3S,3′S-astaxanthin from methanol by tuning the carotenoid synthesis module rationally, optimizing the precursor supply and carotenoid storage globally, thereby achieving a significant elevation in astaxanthin content from 3.910 mg/g to 7.513 mg/g. Thereafter, key node enzyme assembly, branch route reconstruction, and cofactor engineering were employed to further improve astaxanthin accumulation, achieving a significant increase of astaxanthin content to 11.397 mg/g. Finally, the astaxanthin production reached 4.75g/L under fed-batch fermentation, which is the highest astaxanthin level reported in an engineered microbe to date. In addition, the synthesized astaxanthin was successfully and effectively applied in shrimp farming for color enhancement and antioxidant effects. These results demonstrate the potential of K. phaffii as a promising platform for sustainable green production of value-added terpenoid compounds from organic one-carbon feedstocks and will pave the way for astaxanthin industrial production.
Astaxanthin is a valuable xanthophyll carotenoid with potent antioxidant activity and broad industrial applications. This study aimed to enhance astaxanthin production in Rhodosporidium toruloides through sequential chemical mutagenesis and medium optimization. Sequential mutagenesis using benomyl and ethyl methanesulfonate (EMS) generated mutant strain BE1, which produced 2519.39 ± 225.78 µg/L astaxanthin, a 5.70-fold increase over the wild-type strain. BE1 also showed improved growth kinetics, entering the exponential phase at 9 h and reaching maximum astaxanthin accumulation after 96 h. Medium optimization using response surface methodology identified an optimal formulation of 16.78 g/L glucose, 16.61 g/L peptone, and 11.61 g/L malt extract, further increasing astaxanthin production to 3397.13 ± 41.65 µg/L. The crude astaxanthin extract exhibited strong reducing power under the tested conditions. Overall, the combined strategy increased astaxanthin yield progressively from 442.00 µg/L in the wild-type strain to 3397.13 µg/L in the optimized BE1 culture. These findings demonstrate an effective strategy for improving astaxanthin biosynthesis and highlight the industrial potential of BE1 for natural astaxanthin production.
Tuyet Nhung Tran, H. Tran, Hoang Nguyen et al.· IOP Conference Series: Earth...· 0 citations
Local enrichment of acidic residues on the PlGH3 surface could generate a negative electrostatic potential, which enables adaptation to high-salt and alkaline environments, thereby sustaining the enzyme's catalytic activity under such extreme conditions.
Kaijuan Wu, Ke Guo, Zheng Yu et al.· Applied Biochemistry and Bio...· 0 citations
Metabolic engineering of Talaromyces pinophilus through promoter optimization, multicopy integration, and protease deletion enables efficient α-amylase production from lignocellulosic biomass, achieving 26 712 U/mL in bioreactor fermentation.
Jing Zeng, Jianjun Guo, Shuaiwen Zhang et al.· Journal of Industrial Microb...· 0 citations
L-Isoleucine is an essential branched-chain amino acid for livestock and poultry, supporting protein accretion and regulating energy metabolism, immune function, and stress resilience. A genetically stable L-isoleucine producer, Corynebacterium glutamicum cgl-Ile0, was obtained via biosensor-assisted ARTP mutagenesis, and produced 11.52 g/L L-isoleucine in a 5-L fermenter, with a yield of 0.11 g/g and a productivity of 0.24 g/L/h. Whole-genome resequencing revealed four mutations associated with the phenotype, including aspBV346I, asdP27E, brnEL87S, and brnFR28P. Structure-guided protein engineering of two rate-limiting enzymes—threonine dehydratase (TD) and acetohydroxyacid synthase (AHAS)—generated strain cgl-Ile1, increasing titer, yield, and productivity by 39.50%, 27.27%, and 37.50%, respectively, relative to strain cgl-Ile0. Subsequent modular optimization of L-isoleucine biosynthesis, oxaloacetate supply module, cofactor-supply module, and transport/export module yielded the final strain cgl-Ile8. Through optimization pH and dissolved oxygen, the titer, yield and productivity of L-isoleucine produced by strain cgl-Ile8 in a 5-L fermenter were 48.49 g/L, 0.31 g/g and 1.01 g/L/h, which were 4.21-, 2.82-, and 4.21-fold those of strain cgl-Ile0, respectively. Scale-up to a 50-L fermenter further increased the titer, yield and productivity to 50.12 g/L, 0.32 g/g and 1.04 g/L/h, respectively, representing the highest reported L-isoleucine titer in C. glutamicum to date. We developed an industrial L-isoleucine-producing C. glutamicum strain by integrating biosensor-guided ARTP mutagenesis, structure-guided protein engineering, and modular pathway rewiring, providing a practical and transferable framework for constructing GRAS amino-acid producers for animal nutrition.
Junkun Cao, Ming Huang, Qi Sheng et al.· Journal of Animal Science an...· 0 citations
Astaxanthin, a C40 carotenoid with exceptional antioxidant, anti-inflammatory, and anticancer physiological activities, has experienced surging market demand across cosmeceutical, food, and pharmaceutical industries. Traditional astaxanthin production methods have critical limitations, including high costs, significant environmental impact, limited scalability, and stereochemical inadequacies, underscoring the urgent need for alternative production platforms. Metabolic engineering of industrial microorganisms provides a paradigm-shifting solution, leveraging rapid growth, genetic tractability, scalable fermentation, and climate-independent production to achieve sustainable, cost-effective astaxanthin biosynthesis. In this review, we comprehensively review the metabolic engineering strategies employed in non-native astaxanthin producers for higher production of astaxanthin, including directing carbon fluxes toward astaxanthin productivity, balanced expression of either engineered or non-engineered enzymes, their compartmentalization, morphology, and membrane engineering, cofactors, and precursor optimization. Additionally, we highlight emerging technologies aimed at overcoming current bottlenecks faced by non-native producers to advance their industrial applicability and further boost astaxanthin yields toward industrial competitiveness.
