Production of High Levels of 3S,3′S‑Astaxanthin in Yarrowia lipolytica via Iterative Metabolic Engineering

• Published in: Journal of agricultural and food chemistry 2022-03, Vol.70 (8), p.2673-2683
• Main Authors: Zhu, Hang-Zhi, Jiang, Shan, Wu, Jun-Jie, Zhou, Xue-Rong, Liu, Peng-Yang, Huang, Feng-Hong, Wan, Xia
• Format: Article
• Language: English
• Subjects: Biotechnology and Biological Transformations
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.1c08072

Astaxanthin is a highly value-added keto-carotenoid compound. The astaxanthin 3S,3′S-isomer is more desirable for food additives, cosmetics, and pharmaceuticals due to health concerns about chemically synthesized counterparts with a mixture of three isomers. Biosynthesis of 3S,3′S-astaxanthin suffers from limited content and productivity. We engineered Yarrowia lipolytica to produce high levels of 3S,3′S-astaxanthin. We first assessed various β-carotene ketolases (CrtW) and β-carotene hydroxylases (CrtZ) from two algae and a plant. HpCrtW and HpCrtZ from Haematococcus pluvialis exhibited the strongest activity in converting β-carotene into astaxanthin in Y. lipolytica. We then fine-tuned the HpCrtW and HpCrtZ transcriptional expression by increasing the rounds of gene integration into the genome and applied a modular enzyme assembly of HpCrtW and HpCrtZ simultaneously. Next, we rescued leucine biosynthesis in the engineered Y. lipolytica, leading to a five-fold increase in biomass. The astaxanthin production achieved from these strategies was 3.3 g/L or 41.3 mg/g dry cell weight under fed-batch conditions, which is the highest level reported in microbial chassis to date. This study provides the potential for industrial production of 3S,3′S-astaxanthin, and this strategy empowers us to build a sustainable biorefinery platform for generating other value-added carotenoids in the future.