Bettina Schiel-Bengelsdorf

Pathway engineering and synthetic biology using acetogens.

Acetogenic anaerobic bacteria are defined as organisms employing the Wood–Ljungdahl pathway to synthesize acetyl‐CoA from CO2 or CO. Their autotrophic mode of metabolism offers the biotechnological chance to combine use of abundantly available substrates with reduction of greenhouse gases. Several companies have already established pilot and demonstration plants for converting waste gases into ethanol, an important biofuel and a natural product of many acetogens. Recombinant DNA approaches now opened the door to construct acetogens, synthesizing important industrial bulk chemicals and biofuels such as acetone and butanol. Thus, novel microbial production platforms are available that no longer compete with nutritional feedstocks.

The Complete Genome Sequence of Clostridium aceticum: a Missing Link between Rnf- and Cytochrome-Containing Autotrophic Acetogens

ABSTRACT Clostridium aceticum was the first isolated autotrophic acetogen, converting CO2 plus H2 or syngas to acetate. Its genome has now been completely sequenced and consists of a 4.2-Mbp chromosome and a small circular plasmid of 5.7 kbp. Sequence analysis revealed major differences from other autotrophic acetogens. C. aceticum contains an Rnf complex for energy conservation (via pumping protons or sodium ions). Such systems have also been found in C. ljungdahlii and Acetobacterium woodii. However, C. aceticum also contains a cytochrome, as does Moorella thermoacetica, which has been proposed to be involved in the generation of a proton gradient. Thus, C. aceticum seems to represent a link between Rnf- and cytochrome-containing autotrophic acetogens. In C. aceticum, however, the cytochrome is probably not involved in an electron transport chain that leads to proton translocation, as no genes for quinone biosynthesis are present in the genome. IMPORTANCE Autotrophic acetogenic bacteria are receiving more and more industrial focus, as CO2 plus H2 as well as syngas are interesting new substrates for biotechnological processes. They are both cheap and abundant, and their use, if it results in sustainable products, also leads to reduction of greenhouse gases. Clostridium aceticum can use both gas mixtures, is phylogenetically not closely related to the commonly used species, and may thus become an even more attractive workhorse. In addition, its energy metabolism, which is characterized here, and the ability to synthesize cytochromes might offer new targets for improving the ATP yield by metabolic engineering and thus allow use of C. aceticum for production of compounds by pathways that currently present challenges for energy-limited acetogens. Autotrophic acetogenic bacteria are receiving more and more industrial focus, as CO2 plus H2 as well as syngas are interesting new substrates for biotechnological processes. They are both cheap and abundant, and their use, if it results in sustainable products, also leads to reduction of greenhouse gases. Clostridium aceticum can use both gas mixtures, is phylogenetically not closely related to the commonly used species, and may thus become an even more attractive workhorse. In addition, its energy metabolism, which is characterized here, and the ability to synthesize cytochromes might offer new targets for improving the ATP yield by metabolic engineering and thus allow use of C. aceticum for production of compounds by pathways that currently present challenges for energy-limited acetogens.

Complete Genome Sequence of the Type Strain of the Acetogenic Bacterium Moorella thermoacetica DSM 521T

ABSTRACT Here we report the closed genome sequence of the type strain Moorella thermoacetica DSM 521T, an acetogenic bacterium, which is able to grow autotrophically on H2 + CO2 and/or CO, using the Wood-Ljungdahl pathway. The genome consists of a circular chromosome (2.53 Mb).

Complete Genome Sequence of the Acetogenic Bacterium Moorella thermoacetica DSM 2955T

ABSTRACT Here, we report the complete genome sequence of Moorella thermoacetica DSM 2955T, an acetogenic bacterium, which uses the Wood–Ljungdahl pathway for reduction of H2 + CO2 or CO. The genome consists of a single circular chromosome (2.62 Mb).

Complete Genome Sequence of Rnf- and Cytochrome-Containing Autotrophic Acetogen Clostridium aceticum DSM 1496

ABSTRACT Here, we report the closed genome sequence of Clostridium aceticum, an Rnf- and cytochrome-containing autotrophic acetogen that is able to convert CO2 and H2 to acetate using the Wood-Ljungdahl pathway. The genome consists of a circular chromosome (4.2 Mbp) and a small circular plasmid (5.7 kbp).

Genome Sequence of the Acetogenic Bacterium Acetobacterium wieringae DSM 1911T.

ABSTRACT Here, we report the draft genome sequence of Acetobacterium wieringae DSM 1911T, an anaerobic, autotrophic, acetogenic, d,l-lactate-utilizing bacterium. The genome consists of a chromosome (3.88 Mb) and 3,620 predicted protein-encoding genes.

Genome Sequence of the Acetogenic Bacterium Butyribacterium methylotrophicum DSM 3468T

ABSTRACT Butyribacterium methylotrophicum DSM 3468T is an acetogenic methylotrophic, anaerobic, carbon monoxide–oxidizing bacterium that produces acetate, butyrate, and butanol. The genome consists of a single chromosome (4.3 Mb) and harbors 3,989 predicted protein-encoding genes.

Genome Sequence of the Acetogenic Bacterium Oxobacter pfennigii DSM 3222T.

ABSTRACT Here, we report the draft genome sequence of Oxobacter pfennigii DSM 3222T, an anaerobic, acetogenic, carbon monoxide-oxidizing, and butyrate-producing bacterium. The genome consists of a chromosome with a size of 4.49 Mbp.

Draft Genome Sequence of Purine-Degrading Clostridium cylindrosporum HC-1 (DSM 605)

ABSTRACT Here, we report the draft genome sequence of Clostridium cylindrosporum HC-1, a purine- and glycine-fermenting anaerobe, which uses selenoprotein glycine reductase for substrate degradation. The genome consists of a single chromosome (2.72 Mb) and a circular plasmid (14.4 kb).

Draft Genome Sequence of Purine-Degrading Gottschalkia purinilyticum (Formerly Clostridium purinilyticum) WA1 (DSM 1384).

ABSTRACT Here, we report the draft genome sequence of Gottschalkia purinilyticum (formerly Clostridium purinilyticum) WA1, an anaerobic bacterium specialized on degradation of purines (including adenine) and glycine, which uses the selenoprotein glycine reductase for substrate degradation. The genome consists of a single chromosome (3.40 Mb).