High-Yield Production of Lycopene from Corn Steep Liquor and Glycerol Using the Metabolically Engineered <i>Deinococcus radiodurans</i> R1 Strain

Abstract

Developing a highly efficient and ecofriendly system to produce desired products from waste can be considered important to a sustainable society. Here, we report for the first time high-yield production of lycopene through metabolically engineering an extremophilic microorganism, <i>Deinococcus radiodurans</i> R1, from corn steep liquor (CSL) and glycerol. First, the <i>crtLm</i> gene-encoding lycopene cyclase was deleted to prevent the conversion of lycopene to γ-carotene. Then, the <i>crtB</i> gene-encoding phytoene synthase and the <i>dxs</i> gene-encoding 1-deoxy-d-xylulose 5-phosphate synthase were overexpressed to increase carbon flux toward lycopene. The engineered Δ<i>crtLm</i>/<i>crtB</i>^<i>+</i><i>dxs</i>^<i>+</i> <i>D. radiodurans</i> R1 could produce 273.8 mg/L [80.7 mg/g dry cell weight (DCW)] and 373.5 mg/L (108.0 mg/g DCW) of lycopene from 10 g/L of glucose with 5 g/L of yeast extract and 9.9 g/L of glucose with 20 g/L of CSL, respectively. Moreover, the lycopene titer and content were increased by 26% (470.6 mg/L) and 28% (138.2 mg/g DCW), respectively, when the carbon source was changed to glycerol. Finally, fed-batch fermentation of the final engineered strain allowed the production of 722.2 mg/L (203.5 mg/g DCW) of lycopene with a yield and productivity of 20.3 mg/g glycerol and 6.0 mg/L/h, respectively, from 25 g/L of CSL and 35.7 g/L of glycerol.