(191am) Cosmetic and Food Ingredients Produced by Engineered Microbes – the Future of the Industry

Natural flavors and fragrances are currently mainly supplied with plant extracts, which is susceptible to environmental factors, such as pests, disease and weather, price and political volatility and the logistical complexity of sourcing raw materials from farmers in remote location. And the recent changes in consumer perception and regulation have resulted in the increase in demand of natural ingredients in the flavors and fragrances sector. Consequently, there are growing interests in engineering microbes to produce the ingredients from renewable resources. Apocarotenoids, such as α-, β-ionone and retinol, contain many high value compounds in the food and cosmetic industries. Ionones, C13 apocarotenoids, have superior aromatic properties with extremely low odour threshold of less than 1 ppb in air. However, the supply of natural ionones and retinoids is severely limited by their extremely low abundance in nature. For instance, it requires 100 tons of raspberries, or 20 hectares of agricultural area, to produce merely 1 gram of α-ionone. As for retinoids, there is no natural source from plants. Here, an Escherichia coli-based modular system was developed to produce various apocarotenoids. A high lycopene-accumulating strain (~107 mg/L in flasks) was initially obtained by modular optimization of the heterologous mevalonate and lycopene biosynthetic pathways. The lycopene strain served as the chassis for the biosynthesis of different apocarotenoids. Incorporation of enzyme engineering approaches (N-terminal truncation and protein fusion) into modular metabolic engineering strategy significantly improved α-ionone production from 0.5 to 30 mg/L in flasks, and yielded 480 mg/L of α-ionone in fed-batch fermentation. By modifying apocarotenoid genetic module, this platform strain was successfully re-engineered to produce 32 mg/L and 500 mg/L of β-ionone in flask and bioreactor, respectively (> 80-fold higher than previously reported). Similarly, 33 mg/L of retinoids was produced in flask by reconstructing apocarotenoid module, demonstrating the versatility of the “plug-n-play” modular system. Collectively, this study highlights the efficacy of our approaches and sheds light on the bright future of microbial production of food and cosmetic ingredients.