Engineering Acetobacterium Woodii for the Production of Isopropanol and Acetone From Carbon Dioxide and Hydrogen

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[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.Research in Professor Peter Dürre's lab was funded by the ERA-IB7 project OBAC (FKZ 031B0274B). Research in Professor Christian Kennes' lab was also funded by the collaborative European ERA-IB7 project OBAC as well as PCIN2016-148. The authors in the latter laboratory, belonging to the BIOENGIN group, thank Xunta de Galicia for financial support to Competitive Reference Research Groups (ED431C 2021/55)Xunta de Galicia; ED431C 2021/55Alemania. Bundesministerium für Bildung und Forschung (BMBF); 031B0274

Lactate based caproate production with Clostridium drakei and process control of Acetobacterium woodii via lactate dependent in situ electrolysis

Syngas fermentation processes with acetogens represent a promising process for the reduction of CO2 emissions alongside bulk chemical production. However, to fully realize this potential the thermodynamic limits of acetogens need to be considered when designing a fermentation process. An adjustable supply of H2 as electron donor plays a key role in autotrophic product formation. In this study an anaerobic laboratory scale continuously stirred tank reactor was equipped with an All-in-One electrode allowing for in-situ H2 generation via electrolysis. Furthermore, this system was coupled to online lactate measurements to control the co-culture of a recombinant lactate-producing Acetobacterium woodii strain and a lactate-consuming Clostridium drakei strain to produce caproate. When C. drakei was grown in batch cultivations with lactate as substrate, 1.6 g·L−1 caproate were produced. Furthermore, lactate production of the A. woodii mutant strain could manually be stopped and reinitiated by controlling the electrolysis. Applying this automated process control, lactate production of the A. woodii mutant strain could be halted to achieve a steady lactate concentration. In a co-culture experiment with the A. woodii mutant strain and the C. drakei strain, the automated process control was able to dynamically react to changing lactate concentrations and adjust H2 formation respectively. This study confirms the potential of C. drakei as medium chain fatty acid producer in a lactate-mediated, autotrophic co-cultivation with an engineered A. woodii strain. Moreover, the monitoring and control strategy presented in this study reinforces the case for autotrophically produced lactate as a transfer metabolite in defined co-cultivations for value-added chemical production

Internet of Things in Sustainable Energy Systems

Our planet has abundant renewable and conventional energy resources but technological capability and capacity gaps coupled with water-energy needs limit the benefits of these resources to citizens. Through IoT technology solutions and state-of-the-art IoT sensing and communications approaches, the sustainable energy-related research and innovation can bring a revolution in this area. Moreover, by the leveraging current infrastructure, including renewable energy technologies, microgrids, and power-to-gas (P2G) hydrogen systems, the Internet of Things in sustainable energy systems can address challenges in energy security to the community, with a minimal trade-off to environment and culture. In this chapter, the IoT in sustainable energy systems approaches, methodologies, scenarios, and tools is presented with a detailed discussion of different sensing and communications techniques. This IoT approach in energy systems is envisioned to enhance the bidirectional interchange of network services in grid by using Internet of Things in grid that will result in enhanced system resilience, reliable data flow, and connectivity optimization. Moreover, the sustainable energy IoT research challenges and innovation opportunities are also discussed to address the complex energy needs of our community and promote a strong energy sector economy

Anaerobic production of poly(3-hydroxybutyrate) and its precursor 3-hydroxybutyrate from synthesis gas by autotrophic clostridia

Anaerobic production of the biopolymer poly(3-hydroxybutyrate) (PHB) and the monomer 3-hydroxybutyrate (3-HB) was achieved using recombinant clostridial acetogens supplied with syn(thesis) gas as the sole carbon and energy source. 3-HB production was successfully accomplished by a new synthetic pathway containing the genes thlA (encoding thiolase A), ctfA/B (encoding CoA-transferase A/B), and bdhA (encoding (R)-3-hydroxybutyrate dehydrogenase). The respective recombinant Clostridium coskatii [p83_tcb] strain produced autotrophically 0.98 ± 0.12 mM and heterotrophically 21.7 ± 0.27 mM 3-HB. As a proof of concept, production of PHB was achieved using recombinant C. coskatii and Clostridium ljungdahlii strains expressing a novel synthetic PHB pathway containing the genes thlA (encoding thiolase A), hbd (encoding 3-hydroxybutyryl-CoA dehydrogenase), crt (encoding crotonase), phaJ (encoding (R)-enoyl-CoA hydratase), and phaEC (encoding PHA synthase). The strain C. coskatii [p83_PHB_Scaceti] synthesized heterotrophically 3.4 ± 0.29% PHB per cell dry weight (CDW) and autotrophically 1.12 ± 0.12% PHB per CDW

Genome-based metabolic and phylogenomic analysis of three Terrisporobacter species.

Acetogenic bacteria are of high interest for biotechnological applications as industrial platform organisms, however, acetogenic strains from the genus Terrisporobacter have hitherto been neglected. To date, three published type strains of the genus Terrisporobacter are only covered by draft genome sequences, and the genes and pathway responsible for acetogenesis have not been analyzed. Here, we report complete genome sequences of the bacterial type strains Terrisporobacter petrolearius JCM 19845T, Terrisporobacter mayombei DSM 6539T and Terrisporobacter glycolicus DSM 1288T. Functional annotation, KEGG pathway module reconstructions and screening for virulence factors were performed. Various species-specific vitamin, cofactor and amino acid auxotrophies were identified and a model for acetogenesis of Terrisporobacter was constructed. The complete genomes harbored a gene cluster for the reductive proline-dependent branch of the Stickland reaction located on an approximately 21 kb plasmid, which is exclusively found in the Terrisporobacter genus. Phylogenomic analysis of available Terrisporobacter genomes suggested a reclassification of most isolates as T. glycolicus into T. petrolearius

Genome sequencing and description of Oerskovia enterophila VJag, an agar- and cellulose-degrading bacterium

Abstract A nonmotile, Gram-positive bacterium that shows an elongated and branching cell shape was isolated from soil samples from the botanical garden of Ulm University, Ulm, Germany. Here, the isolation procedure, identification, genome sequencing and metabolic features of the strain are described. Phylogenetic analysis allowed to identify the isolated strain as Oerskovia enterophila. The genus Oerskovia belongs to the family Cellulomonadaceae within the order Actinomycetales. The length of cells of O. enterophila ranges from 1 μm to 15 μm, depending on the growth phase. In the exponential growth phase, cells show an elongated and branching shape, whereas cells break up to round or coccoid elements in the stationary growth phase. The 4,535,074 bp long genome consists of 85 contigs with 3918 protein-coding genes and 57 RNA genes. The isolated strain was shown to degrade numerous complex carbon sources such as cellulose, chitin, and starch, which can be found ubiquitously in nature. Moreover, analysis of the genomic sequence revealed the genetic potential to degrade these compounds

Syntrophic microbial communities on straw as biofilm carrier increase the methane yield of a biowaste-digesting biogas reactor

Biogas from biowaste can be an important source of renewable energy, but the fermentation process of low-structure waste is often unstable. The present study uses a full-scale biogas reactor to test the hypothesis that straw as an additional biofilm carrier will increase methane yield; and this effect is mirrored in a specific microbial community attached to the straw. Better reactor performance after addition of straw, at simultaneously higher organic loading rate and specific methane yield confirmed the hypothesis. The microbial communities on straw as a biofilm carrier and of the liquid reactor content were investigated using 16S rDNA amplicon sequencing by means of 454 pyrosequencing technology. The results revealed high diversity of the bacterial communities in the liquid reactor content as well as the biofilms on the straw. The most abundant archaea in all samples belonged to the genera Methanoculleus and Methanosarcina. Addition of straw resulted in a significantly different microbial community attached to the biofilm carrier. The bacterium Candidatus Cloacamonas acidaminovorans and methanogenic archaea of the genus Methanoculleus dominated the biofilm on straw. Syntrophic interactions between the hydrogenotrophic Methanoculleus sp. and members of the hydrogen-producing bacterial community within biofilms may explain the improved methane yield. Thus, straw addition can be used to improve and to stabilize the anaerobic process in substrates lacking biofilm-supporting structures

Functional annotation of genes from the <i>Terrisporobacter</i> type strain genomes into KEGG categories.

The y-axis shows the different functional KEGG categories and the x-axis the number of genes assigned to each category by BlastKOALA. The bar color indicates the number of genes assigned for the three Terrisporobacter type strains T. mayombei (green), T. petrolearius (blue) and T. glycolicus (red).</p