Metabolic engineering of Bacillus subtilis for terpenoid production.

Zheng Guan,Guiyuan Lv,Linda Dijkshoorn,Rita Setroikromo,Dan Xue,Ingy I Abdallah,Wim J Quax

doi:10.1007/s00253-015-6950-1

Abstract

Terpenoids are the largest group of small-molecule natural products, with more than 60,000 compounds made from isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). As the most diverse group of small-molecule natural products, terpenoids play an important role in the pharmaceutical, food, and cosmetic industries. For decades, Escherichia coli (E. coli) and Saccharomyces cerevisiae (S. cerevisiae) were extensively studied to biosynthesize terpenoids, because they are both fully amenable to genetic modifications and have vast molecular resources. On the other hand, our literature survey (20 years) revealed that terpenoids are naturally more widespread in Bacillales. In the mid-1990s, an inherent methylerythritol phosphate (MEP) pathway was discovered in Bacillus subtilis (B. subtilis). Since B. subtilis is a generally recognized as safe (GRAS) organism and has long been used for the industrial production of proteins, attempts to biosynthesize terpenoids in this bacterium have aroused much interest in the scientific community. This review discusses metabolic engineering of B. subtilis for terpenoid production, and encountered challenges will be discussed. We will summarize some major advances and outline future directions for exploiting the potential of B. subtilis as a desired “cell factory” to produce terpenoids.

Highlights

Nature provides an infinite treasure of complex molecules (Wilson and Danishefsky 2006) which have served as leads and scaffolds for drug discovery in the past centuries (Newman and Cragg 2007; Newman and Cragg 2012; Newman et al 2003)
The Dictionary of Natural Products describes approximately 359 types of terpenoids, which comprise 64,571 compounds. Since these terpenoids account for ca. 24.11 % (64,571 of 267,783) of all natural products and are required for biological functions in all living creatures, they indisputably play a dominant role in both the scientific community and the commercial world (Breitmaier 2006)
The results show that the emission of isoprene is severely decreased without the genes encoding dxs, ispD, ispF, or ispH, indicating their importance in the methylerythritol phosphate (MEP) pathway

Summary

Introduction

Nature provides an infinite treasure of complex molecules (Wilson and Danishefsky 2006) which have served as leads and scaffolds for drug discovery in the past centuries (Newman and Cragg 2007; Newman and Cragg 2012; Newman et al 2003). Research into the progress of genetic engineering of MEP pathway enzymes in B. subtilis can provide more direct support for utilizing B. subtilis as a microbial host for terpenoid biosynthesis. Xue and Ahring first tried to enhance isoprene production by modifying the MEP pathway in B. subtilis They overexpressed the dxs and dxr genes. Zhou overexpressed dxs and idi genes along with introducing ads (ads encodes the synthase which cyclizes farnesyl diphosphate into amorphadiene) in B. subtilis and got the highest yield of amorphadiene (∼20 mg/L) at shake-flask scale They thought that the lack of genetic tools for fine-tuning the expression of multiple genes is the bottleneck in production of terpenoids in B. subtilis. This Colorado research group focused on the isoprene biosynthesis mechanism

Method

Findings

Summary