Engineering Acetobacterium woodii for the production of isopropanol and acetone from carbon dioxide and hydrogen

Abstract

The capability of four genetically modified Acetobacterium woodii strains for improved production of acetone from CO2 and hydrogen was tested. The acetone biosynthesis pathway was constructed by combining genes from Clostridium acetobutylicum and Clostridium aceticum. Expression of acetone production genes was demonstrated in all strains. In bioreactors with continuous gas supply, all produced acetic acid, acetone, and, surprisingly, isopropanol. The production of isopropanol was caused by an endogenous secondary alcohol dehydrogenase (SADH) activity at low gas‐feeding rate. Although high amounts of the natural end product acetic acid of A. woodii were formed,14.5 mM isopropanol and 7.6 mM acetone were also detected, showing that this is a promising approach for the production of new solvents from C1 gases. The highest acetic acid, acetone, and isopropanol production was detected in the recombinant A. woodii [pJIR750_ac1t1] strain, with final concentrations of 438 mM acetic acid, 7.6 mM acetone, and 14.5 mM isopropanol. The engineered strain A. woodii [pJIR750_ac1t1] was found to be the most promising strain for acetone production from a gas mixture of CO2 and H2 and the formation of isopropanol in A. woodii was shown for the first time.

Metabolomics-based analysis in Daphnia magna after exposure to low environmental concentrations of polystyrene nanoparticles

“…Microorganisms, for example Lactobacillus brevis , Clostridium beijerinckii , C. aurantibutyricum , C. ragsdalei , and Acetobacterium woodii , are known to produce isopropanol from acetone. 67–69 The decrease detected here might indicate that the bacterial conversion of acetone to isopropanol through isopropanol dehydrogenase is affected. 70…”

Recent advances in applying omic technologies for studying acetic acid bacteria in industrial vinegar production: A comprehensive review

“…[ 90 ] In this process, cytoplasmic acetic acid can be completely oxidized to carbon dioxide (CO 2 ) and water (H 2 O), yielding adenosine triphosphate (ATP) and simultaneously detoxifying the cell through a well‐known overoxidation reaction. [ 91,92 ] The enzyme acetyl‐CoA synthase (Acs) plays a critical role in this pathway. Acs catalyzes the conversion of acetate into acetyl‐CoA, facilitating its entry into the TCA cycle.…”

“…and simultaneously detoxifying the cell through a well-known overoxidation reaction. [91,92] The enzyme acetyl-CoA synthase (Acs) plays a critical role in this pathway. Acs catalyzes the conversion of acetate into acetyl-CoA, facilitating its entry into the TCA cycle.…”

Production of biofuels from C1‐gases with Clostridium and related bacteria—Recent advances

“…This process can take place through three different mechanisms: (a) direct production of alcohols by acetogenic/solventogenic strains (Figure 1a ), (b) mixotrophic fermentation of both gases and soluble substrates has recently also been addressed (Figure 1b ), (c) indirect production combining syngas fermentation (performed by acetogenic bacteria) and chain elongation (commonly performed by species such as C. kluyveri ) (Figure 1c ). Concerning the first strategy, solvents can be produced by different acetogens from CO/CO 2 /H 2 in various ratios and mixtures, including mainly Clostridium carboxidivorans (Fernández‐Naveira et al, 2017a ), Clostridium aceticum (Arslan et al, 2019 ), Clostridium ljungdahlii (Richter et al, 2016 ), Clostridium ragsdalei (Sun et al, 2018 ), Clostridium autoethanogenum (Liew et al, 2017 ), Moorella thermoacetica (Takemura et al, 2021 ), Acetobacterium woodii (Arslan et al, 2022 ), Eubacterium limosum (Litty & Müller, 2021 ) and Thermoanaerobacter kivui (Maru et al, 2018 ). Therefore, these species are currently of particular interest because they can use greenhouse gases (e.g.…”