Isopropanol production with engineered Cupriavidus necator as bioproduction platform

Abstract

Alleviating our society's dependence on petroleum-based chemicals has been highly emphasized due to fossil fuel shortages and increasing greenhouse gas emissions. Isopropanol is a molecule of high potential to replace some petroleum-based chemicals, which can be produced through biological platforms from renewable waste carbon streams such as carbohydrates, fatty acids, or CO2. In this study, for the first time, the heterologous expression of engineered isopropanol pathways were evaluated in a Cupriavidus necator strain Re2133, which was incapable of producing poly-3-hydroxybutyrate [P(3HB)]. These synthetic production pathways were rationally designed through codon optimization, gene placement, and gene dosage in order to efficiently divert carbon flow from P(3HB) precursors toward isopropanol. Among the constructed pathways, Re2133/pEG7c overexpressing native C. necator genes encoding a β-ketothiolase, a CoA-transferase, and codon-optimized Clostridium genes encoding an acetoacetate decarboxylase and an alcohol dehydrogenase produced up to 3.44 g l(-1) isopropanol in batch culture, from fructose as a sole carbon source, with only 0.82 g l(-1) of biomass. The intrinsic performance of this strain (maximum specific production rate 0.093 g g(-1) h(-1), yield 0.32 Cmole Cmole(-1)) corresponded to more than 60 % of the respective theoretical performance. Moreover, the overall isopropanol production yield (0.24 Cmole Cmole(-1)) and the overall specific productivity (0.044 g g(-1) h(-1)) were higher than the values reported in the literature to date for heterologously engineered isopropanol production strains in batch culture. Strain Re2133/pEG7c presents good potential for scale-up production of isopropanol from various substrates in high cell density cultures.

Efficient solar-to-fuels production from a hybrid microbial–water-splitting catalyst system

“…Cessation of growth due to nitrogen depletion was followed by a rapid increase in isopropanol production. This decoupling of growth and product synthesis is consistent with the previously reported behavior of this strain under fructose-fed conditions (42) and with pyruvate synthesis kinetics in other PHB − strains of R. eutropha (44).…”

“…1. The strain, engineered by Grousseau et al (42), produces isopropanol at high yield under fructose-fed, nutrient-limited conditions. As summarized in Fig.…”

Water Splitting–Biosynthetic Hybrid System for CO2 Conversion using Nickel Nanoparticles Embedded in N‐Doped Carbon Nanotubes

“…[37] The electrochemical property,b iocompatibility,a nd CO 2 conversion efficiency of the Ni@N-C were systematically studied to reveal the coupling mechanism. In this Ni@N-Cc omplex, the Ni nanoparticles are embedded within the N-doped carbon nanotubes.…”

Characterisation of a 3-hydroxypropionic acid-inducible system from Pseudomonas putida for orthogonal gene expression control in Escherichia coli and Cupriavidus necator

“…Chemicals and fuels can be produced from renewable or waste feedstocks using metabolically engineered microorganisms, which may aid to reducing greenhouse gas emissions 1–3 . Recently, significant research efforts have been directed towards developing microorganisms for the biosynthesis of value-added chemicals, including 3-hydroxypropionic acid (3-HP) 4–7 .…”