Control of n-Butanol Induced Lipidome Adaptations in E. coli.

Aike Jeucken,Miaomiao Zhou,Marc M S M Wösten,Jos F Brouwers

doi:10.3390/metabo11050286

Abstract

The versatile compound n-butanol is one of the most promising biofuels for use in existing internal combustion engines, contributing to a smooth transition towards a clean energy society. Furthermore, n-butanol is a valuable resource to produce more complex molecules such as bioplastics. Microbial production of n-butanol from waste materials is hampered by the biotoxicity of n-butanol as it interferes with the proper functioning of lipid membranes. In this study we perform a large-scale investigation of the complete lipid-related enzyme machinery and its response to exposure to a sublethal concentration of n-butanol. We profiled, in triplicate, the growth characteristics and phospholipidomes of 116 different genetic constructs of E. coli, both in the presence and absence of 0.5% n-butanol (v/v). This led to the identification of 230 lipid species and subsequently to the reconstruction of the network of metabolites, enzymes and lipid properties driving the homeostasis of the E. coli lipidome. We were able to identify key lipids and biochemical pathways leading to altered n-butanol tolerance. The data led to new conceptual insights into the bacterial lipid metabolism which are discussed.

Highlights

The biosynthesis of n-butanol has received much attention over the past decades because of its potential in many different processes, most particular as a biofuel [1,2,3].Chemical advantages of n-butanol over other biofuels are the high energy content and low hygroscopic- and corrosive properties
We found a 50% inhibition of growth rate at 0.5% n-butanol (v/v) and chose to explore changes in lipid metabolism at this concentration
In E. coli, the phospholipidome is controlled by a relatively modest set of 68 proteins of which only 20 are essential. These proteins are organized in several pathways related to fatty acid synthesis or -breakdown, glycerol backbone metabolism or are related to phospholipid modifications or -synthesis

Summary

Introduction

The biosynthesis of n-butanol has received much attention over the past decades because of its potential in many different processes, most particular as a biofuel [1,2,3].Chemical advantages of n-butanol over other biofuels are the high energy content and low hygroscopic- and corrosive properties. N-butanol has many other applications in chemistry such as in the production of paints, resins and plastics [7,8]. Bacterial strains of Clostridium have long been the model organisms for n-butanol production via acetone-butanol-ethanol fermentation (reviewed in [9]). Yields have remained rather low despite metabolic re-engineering and applying advanced co-cultures of micro-organisms [9,10,11]. This has spiked interest in engineering other model organisms such as Saccharomyces and Escherichia coli to produce n-butanol because of their excellent genetic accessibility [12,13,14,15]

Methods

Results

Conclusion