Department of Molecular Science and Technology, Department of Applied Chemical and Biological Engineering, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, 16499, Republic of Korea.
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
Microb Cell Fact. 2024 Jan 4;23(1):10. doi: 10.1186/s12934-023-02287-9.
Crocin, a glycosylated apocarotenoid pigment predominantly found in saffron, has garnered significant interest in the field of biotechnology for its bioactive properties. Traditional production of crocins and their aglycone, crocetin, typically involves extraction from crocin-producing plants. This study aimed to develop an alternative biosynthetic method for these compounds by engineering the metabolic pathways of zeaxanthin, crocetin, and crocin in Escherichia coli strains.
Employing a series of genetic modifications and the strategic overexpression of key enzymes, we successfully established a complete microbial pathway for synthesizing crocetin and four glycosylated derivatives of crocetin, utilizing glycerol as the primary carbon source. The overexpression of zeaxanthin cleavage dioxygenase and a novel variant of crocetin dialdehyde dehydrogenase resulted in a notable yield of crocetin (34.77 ± 1.03 mg/L). Further optimization involved the overexpression of new types of crocetin and crocin-2 glycosyltransferases, facilitating the production of crocin-1 (6.29 ± 0.19 mg/L), crocin-2 (5.29 ± 0.24 mg/L), crocin-3 (1.48 ± 0.10 mg/L), and crocin-4 (2.72 ± 0.13 mg/L).
This investigation introduces a pioneering and integrated microbial synthesis method for generating crocin and its derivatives, employing glycerol as a sustainable carbon feedstock. The substantial yields achieved highlight the commercial potential of microbial-derived crocins as an eco-friendly alternative to plant extraction methods. The development of these microbial processes not only broadens the scope for crocin production but also suggests significant implications for the exploitation of bioengineered compounds in pharmaceutical and food industries.
藏红花中的主要糖苷类类胡萝卜素色素——西红花苷，因其生物活性而在生物技术领域引起了广泛关注。传统的西红花苷及其苷元西红花酸的生产通常涉及从藏红花植物中提取。本研究旨在通过工程改造大肠杆菌中玉米黄质、西红花酸和西红花苷的代谢途径，开发这些化合物的替代生物合成方法。
采用一系列遗传修饰和关键酶的策略性过表达，我们成功建立了一条利用甘油作为主要碳源合成西红花酸和四个西红花酸糖苷衍生物的完整微生物途径。过表达玉米黄质裂解双加氧酶和新型西红花酸二醛脱氢酶，使西红花酸的产量显著提高（34.77±1.03mg/L）。进一步优化涉及新型西红花酸和西红花苷-2 糖基转移酶的过表达，从而促进了西红花苷-1（6.29±0.19mg/L）、西红花苷-2（5.29±0.24mg/L）、西红花苷-3（1.48±0.10mg/L）和西红花苷-4（2.72±0.13mg/L）的生产。
本研究引入了一种开创性的、综合的微生物合成方法，用于生成西红花苷及其衍生物，以甘油为可持续的碳源。所获得的高产量突出了微生物衍生西红花苷作为植物提取方法的环保替代品的商业潜力。这些微生物工艺的开发不仅拓宽了西红花苷生产的范围，而且对制药和食品工业中生物工程化合物的开发具有重要意义。
