Co-localizing key pathway enzymes by protein scaffold to enhance geraniol production in Escherichia coli

Abstract

The key point of geraniol as an isoprenoid biofuel is the yield, however, the toxicity problem caused by the accumulation of intermediate metabolites hinders the high yield of geraniol. A promising strategy to accelerate cascade processes and reduce toxic effects of intermediates is co-localization of biosynthetic enzymes. In this study, a protein scaffold was employed to co-localize three key enzymes involved in the production of geraniol. The co-localization strategy significantly increased the rate and yield of geraniol synthesis by reducing the impact of intermediates on cell growth. However, the system’s limited supply of glycerol proved to be a major obstacle to further optimizing geraniol production. In order to overcome this limitation, we conducted a systematic optimization of the culture conditions. Moreover, fed-batch fermentation produced a geraniol yield of 2102.5 mg/L, an increase of 1.44 times over the original non-scaffold strain (1460.6 mg/L) capacity. This study demonstrates the effectiveness of co-localization of biosynthetic enzymes to promote geraniol production and provides a promising strategy for boosting the production of other monoterpenes in Escherichia coli.