Lycopene has been widely applied in the food and medical fields due to having antioxidant, anticancer, and anti-inflammatory properties. Traditional lycopene production processes including natural extraction and chemical synthesis cannot meet the growing market demand and the pursuit for natural products of consumers. Microbial synthesis of lycopene has offered a promising alternative owing to its unique advantages. Industrial yeasts can produce lycopene by introducing heterologous synthetic pathways, which have become a reliable process to replace plants for lycopene production. In order to increase the lycopene production in industrial yeast, some strategies such as increasing the supply of precursors, looking for the optimal combination of lycopene synthesis genes, modularizing the enzymes in the metabolic pathway, increasing the content of cofactors, reducing product toxicity to cells, and optimizing fermentation methods make industrial yeast an effective strain for producing lycopene. This review mainly summarizes the research progress of lycopene produced by several industrial yeasts, analyzes the factors affecting the lycopene synthesis in the metabolic pathways, and summarizes and prospects the methods and strategies used to achieve high yields of lycopene in yeast to help with future research.

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Glycerol is a byproduct generated in large amounts during the process of biodiesel production. The present study reports an alternative method of crude glycerol valorization for the production of citric and malic acid by Yarrowia lipolytica. To enhance the conversion efficiency, we comprehensively investigated optimization of the carbon source, nitrogen source, and pH regulation strategy. Under optimal conditions with the initial concentration of crude glycerol at 40 g/L in combination with 0.3 g/L NH4Cl as the nitrogen source and pH at 4.0 using Na2CO3, we finally obtained 81.11 g/L citric acid and 24.90 g/L malic acid using fed-batch fermentation. In addition, acetate was found to enhance organic acid production and regulate carbon flow among organic acids from crude glycerol. The present study provides an alternative approach for valorization of crude glycerol into value-added biochemicals.

β-Carotene is a kind of high-value tetraterpene compound, which shows various applications in medical, agricultural and industrial areas owing to its antioxidant, anti-tumor and anti-inflammatory activities. In this study, Yarrowia lipolytica was successfully metabolically modified through the construction and optimization of β-carotene biosynthetic pathway for β-carotene production. The β-carotene titer in the engineered strain Yli-C with the introduction of the carotenogenesis genes crtI crtE and crtYB can reach 34.5 mg/L. With the overexpression of key gene in MVA pathway and the enhanced expression of fatty acid synthesis pathway, the β-carotene titer of the engineered strain Yli-CAH reached 87 mg/L, which was 152% higher than that of the strain Yli-C. Through the further expression of the rate-limiting enzyme tHMGR and the copy number of β-carotene synthesis related genes, the β-carotene production of Yli-C2AH2 strain reached 117.5 mg/L. The final strain Yli-C2AH2 produced 2.7 g/L β-carotene titer by fed-batch fermentation in a 5.0 L fermenter. This research will greatly speed up the process of developing microbial cell factories for the commercial production of β-carotene.

β-Carotene is a kind of high-value tetraterpene compound, which shows various applications in medical, agricultural and industrial areas owing to its antioxidant, anti-tumor and anti-inflammatory activities. In this study, Yarrowia lipolytica was successfully metabolically modified through the construction and optimization of β-carotene biosynthetic pathway for β-carotene production. The β-carotene titer in the engineered strain Yli-Cwith the introduction of the carotenogenesis genes crtI, crtEand crtYB can reach 34.5 mg/L. With the overexpression of key gene in MVA pathway and the enhanced expression of fatty acid synthesis pathway, the β-carotene titer of the engineered strain Yli-CAH reached 87 mg/L, which was 152% higher than that of the strain Yli-C. Through the further expression of the rate-limiting enzyme tHMGR and the copy number of β-carotene synthesis related genes, the β-carotene production of Yli-C2AH2 strain reached 117.5 mg/L. The final strain Yli-C2AH2 produced 2695.5 mg/L β-carotene titer by fed-batch fermentation in a 5.0 L fermenter. This research will greatly speed up the process of developing microbial cell factories for the commercial production of β-carotene.