Enhanced Lycopene Production in Escherichia coli by Expression of Two MEP Pathway Enzymes from Vibrio sp. Dhg

Hyun Gyu Lim,Gyoo Yeol Jung,Sunghwa Woo,Min Jae Kim,Myung Hyun Noh

doi:10.3390/catal9121003

Abstract

Microbial production is a promising method that can overcome major limitations in conventional methods of lycopene production, such as low yields and variations in product quality. Significant efforts have been made to improve lycopene production by engineering either the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway or mevalonate (MVA) pathway in microorganisms. To further improve lycopene production, it is critical to utilize metabolic enzymes with high specific activities. Two enzymes, 1-deoxy-d-xylulose-5-phosphate synthase (Dxs) and farnesyl diphosphate synthase (IspA), are required in lycopene production using MEP pathway. Here, we evaluated the activities of Dxs and IspA of Vibrio sp. dhg, a newly isolated and fast-growing microorganism. Considering that the MEP pathway is closely related to the cell membrane and electron transport chain, the activities of the two enzymes of Vibrio sp. dhg were expected to be higher than the enzymes of Escherichia coli. We found that Dxs and IspA in Vibrio sp. dhg exhibited 1.08-fold and 1.38-fold higher catalytic efficiencies, respectively. Consequently, the heterologous overexpression improved the specific lycopene production by 1.88-fold. Our findings could be widely utilized to enhance production of lycopene and other carotenoids.

Highlights

Carotenoids are natural pigments present in plants and microorganisms [1]
A synthetic expression cassette was reported for lycopene production in E. coli [4,34]
While the overexpression of crtEBI was helpful in increasing lycopene production, the main difference was attributed to the higher catalytic efficiencies of Vibrio sp. dhg derived enzymes

Summary

Introduction

Carotenoids are natural pigments present in plants and microorganisms [1]. Some carotenoids are known to function as membrane protective anti-oxidants [2,3], which has led to a high demand for carotenoids for medical and pharmaceutical applications [4,5]. Lycopene is one of the most highly valuable carotenoids owing to its potent antioxidant [6] and disease prevention properties [7,8]. The lycopene market is growing at 3.5 percent annually and is expected to exceed 133 million dollars in. 2023, supporting high demand and value [9,10]. The industrial production of carotenoids has conventionally been conducted through an extraction from many natural products, such as tomato and watermelon [11]. The extraction method does not meet the growing demand due to limited supply of natural products [12,13]. Its stable production is difficult because of fluctuating lycopene content of natural products: 0.00540–1.50 g lycopene/kg of tomato paste [14], Catalysts 2019, 9, 1003; doi:10.3390/catal9121003 www.mdpi.com/journal/catalysts

Results

Discussion

Conclusion