Metabolic Engineering and Synthetic Biology approaches for sustainable and efficient production of carotenoids in yeast

类胡萝卜素是植物、细菌或真菌中的主要成分，可作为维生素A的前体、强大的抗氧化剂或对各种疾病的保护剂，如炎症、衰老、白内障、癌症、肥胖、心血管和神经退行性疾病。由于这些生物活性，类胡萝卜素对人类和动物的健康是必不可少的，必须通过食物摄入。这种需求产生了对类胡萝卜素产品日益增长的商业兴趣，如营养食品、食品补充剂和着色剂。为了满足市场需求，合成类胡萝卜素在80%-90%的应用中使用。这些已显示减少生物活性和健康问题，不被批准用于人类消费，但主要用于水产养殖和动物饲料部门的着色剂。天然类胡萝卜素是通过从自然来源提取或通过发酵在微生物中生物产生的，比有机合成的费用更高。在这里，我们将开发一种利用面包酵母生产天然类胡萝卜素的具有成本效益的策略，旨在取代主要应用中的合成类胡萝卜素，并优化生产，以达到盈亏平衡或更高的产量。我们将开发生产虾青素和岩藻黄素的专用酵母平台。我们将整合代谢工程和计算生物学的前沿方法，以提高胡萝卜素生成酶的活性，并将酵母中的代谢物流量重新定向为类胡萝卜素的生产。我们还将操纵类胡萝卜素进出细胞的运输，以实现持续生产和快速恢复。最后，我们将通过应用机器学习算法来构建最优生物反应器参数、细胞生长和产量以及类胡萝卜素产品图谱分析的模型，从而加速生物过程的开发和优化。酵母类胡萝卜素将在不同层面对加拿大农业食品部门产生积极影响：1.更健康的水产养殖和动物饲料产品；2.更便宜和更容易获得的膳食补充剂和营养食品；3.进一步生产其他类胡萝卜素的微生物平台；4.以类胡萝卜素为基础的益生菌的开发选择。

Carotenoids are major constituents in plant, bacteria or fungi that act as precursors of Vitamin A, strong antioxidants or protective agents against various conditions, such as inflammation, aging, cataract, cancer, obesity, cardiovascular and neurodegenerative diseases. Owing to these biological activities, carotenoids are essential for human and animal health that must be ingested by food. This need has generated a growing commercial interest for carotenoid-based products as nutraceuticals, food supplements, colorants. To fulfill the market demands, synthetic carotenoids are used in 80-90 % of applications. These have shown reduces bioactivities and health issues and not approved for human consumption, but mainly used for coloration purposes in aquaculture and animal feed sector. Natural carotenoids are obtained by extraction from natural sources or biologically produced in microbes by fermentation at higher expenses than for organic synthesis. Here, we will develop a cost-effective strategy for production of natural carotenoids using baker's yeast, aiming replace synthetic carotenoids in major applications and optimize production to achieve yields at breakeven point or above. We will develop dedicated yeast platforms for production of astaxanthin and fucoxanthin. We will integrate cutting edge approaches in metabolic engineering and computational biology to improve the activity of carotenogenic enzymes and redirect metabolite fluxes in yeast toward carotenoid production. We will also manipulate carotenoid transport in and out of the cells to enable sustained production and facile recovery. Finally, we will accelerate the bioprocess development and optimization by applying Machine Learning algorithms to construct a model of optimal bioreactor parameters, cell growth and production rates and carotenoid product profile analysis. Yeast-made carotenoids will positively impact the Canadian Agri-food sector at different levels: 1. Healthier aquaculture and animal feed products; 2. Cheaper and more available dietary supplements and nutraceuticals; 3. Microbial platforms for further production of other carotenoids; 4. Options for development of carotenoid-based probiotics.