Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
J Agric Food Chem. 2024 Apr 17;72(15):8664-8673. doi: 10.1021/acs.jafc.4c00377. Epub 2024 Apr 2.
Retinol is a lipid-soluble form of vitamin A that is crucial for human visual and immune functions. The production of retinol through microbial fermentation has been the focus of recent exploration. However, the obtained titer remains limited and the product is often a mixture of retinal, retinol, and retinoic acid, necessitating purification. To achieve efficient biosynthesis of retinol in , we improved the metabolic flux of β-carotene to provide sufficient precursors for retinol in this study. Coupled with the optimization of the expression level of β-carotene 15,15'-dioxygenase, production of retinol was achieved. Furthermore, Tween 80 was used as an extractant and butylated hydroxytoluene as an antioxidant to extract intracellular retinol and prevent retinol oxidation, respectively. This strategy significantly increased the level of retinol production. By optimizing the enzymes converting retinal to retinol, the proportion of extracellular retinol in the produced retinoids reached 100%, totaling 1042.3 mg/L. Finally, total retinol production reached 5.4 g/L through fed-batch fermentation in a 5 L bioreactor, comprising 4.2 g/L extracellular retinol and 1.2 g/L intracellular retinol. This achievement represents the highest reported titer so far and advances the industrial production of retinol.
视黄醇是维生素 A 的一种脂溶性形式,对人类的视觉和免疫功能至关重要。通过微生物发酵生产视黄醇一直是最近研究的重点。然而,得到的产量仍然有限,而且产品通常是视黄醛、视黄醇和维甲酸的混合物,需要进行纯化。为了在 中高效合成视黄醇,我们在这项研究中改进了β-胡萝卜素的代谢通量,为视黄醇提供了足够的前体。结合β-胡萝卜素 15,15'-加氧酶表达水平的优化,实现了视黄醇的生产。此外,使用吐温 80 作为提取剂,叔丁基对苯二酚作为抗氧化剂,分别提取细胞内视黄醇并防止视黄醇氧化。该策略显著提高了视黄醇的产量。通过优化将视黄醛转化为视黄醇的酶,所产生的类视黄醇中外源视黄醇的比例达到 100%,总计为 1042.3mg/L。最后,通过在 5L 生物反应器中进行分批补料发酵,总视黄醇产量达到 5.4g/L,其中包括 4.2g/L 细胞外视黄醇和 1.2g/L 细胞内视黄醇。这一成就代表了迄今为止报道的最高产量,推进了视黄醇的工业化生产。