Targeted Cell Labeling and Sorting of Prokaryotes for Cultivation and Omics Approaches.

To date, the vast majority of prokaryotic organisms escapes detailed characterization because they cannot be isolated in axenic cultures. These organisms are referred to as microbial dark matter. Targeted labelling and sorting of these microorganisms pave the way for single-cell, enrichment, or cultivation approaches.

Extracellular riboflavin induces anaerobic biofilm formation in Shewanella oneidensis.

Background: Some microorganisms can respire with extracellular electron acceptors using an extended electron transport chain to the cell surface. This process can be applied in bioelectrochemical systems in which the organisms produce an electrical current by respiring with an anode as electron acceptor. These organisms apply flavin molecules as cofactors to facilitate one-electron transfer catalyzed by the terminal reductases and in some cases as endogenous electron shuttles.

Improvement of the electron transfer rate in Shewanella oneidensis MR-1 using a tailored periplasmic protein composition.

Periplasmic c-type cytochromes are essential for the electron transport between the cytoplasmic membrane bound menquinol oxidase CymA and the terminal ferric iron reductase MtrABC in the outer membrane of Shewanella oneidensis cells. Either STC or FccA are necessary for periplasmic electron transfer. We followed the hypothesis that the elimination of potential competing reactions in the periplasm and the simultaneous overexpression of STC (cctA) could lead to an accelerated electron transfer to the cell surface.

Chromate Resistance Mechanisms in Leucobacter chromiiresistens.

Chromate is one of the major anthropogenic contaminants on Earth. is a highly chromate-resistant strain, tolerating chromate concentrations in LB medium of up to 400 mM. In response to chromate stress, forms biofilms, which are held together via extracellular DNA.

Development of a production chain from vegetable biowaste to platform chemicals.

Background: A future bioeconomy relies on the development of technologies to convert waste into valuable compounds. We present here an attempt to design a biotechnological cascade for the conversion of vegetable waste into acetoin and electrical energy.

Results: A vegetable waste dark fermentation effluent containing mainly acetate, butyrate and propionate was oxidized in a bioelectrochemical system.

Extracellular Electron Transfer and Biosensors.

This chapter summarizes in the beginning our current understanding of extracellular electron transport processes in organisms belonging to the genera Shewanella and Geobacter. Organisms belonging to these genera developed strategies to transport respiratory electrons to the cell surface that are defined by modules of which some seem to be rather unique for one or the other genus while others are similar. We use this overview regarding our current knowledge of extracellular electron transfer to explain the physiological interaction of microorganisms in direct interspecies electron transfer, a process in which one organism basically comprises the electron acceptor for another microbe and that depends also on extended electron transport chains.

Unbalanced fermentation of glycerol in Escherichia coli via heterologous production of an electron transport chain and electrode interaction in microbial electrochemical cells.

Microbial electrochemical cells are an emerging technology for achieving unbalanced fermentations. However, organisms that can serve as potential biocatalysts for this application are limited by their narrow substrate spectrum. This study describes the reprogramming of Escherichia coli for the efficient use of anodes as electron acceptors.

A dynamic periplasmic electron transfer network enables respiratory flexibility beyond a thermodynamic regulatory regime.

Microorganisms show an astonishing versatility in energy metabolism. They can use a variety of different catabolic electron acceptors, but they use them according to a thermodynamic hierarchy, which is determined by the redox potential of the available electron acceptors. This hierarchy is reflected by a regulatory machinery that leads to the production of respiratory chains in dependence of the availability of the corresponding electron acceptors.

Draft genome sequence of Leucobacter chromiiresistens, an extremely chromium-tolerant strain.

Here we present the draft genome of Leucobacter chromiiresistens. This is the first genome sequence of an organism belonging to the genus Leucobacter. L.

Investigation of the electron transport chain to and the catalytic activity of the diheme cytochrome c peroxidase CcpA of Shewanella oneidensis.

Bacterial diheme c-type cytochrome peroxidases (BCCPs) catalyze the periplasmic reduction of hydrogen peroxide to water. The gammaproteobacterium Shewanella oneidensis produces the peroxidase CcpA under a number of anaerobic conditions, including dissimilatory iron-reducing conditions. We wanted to understand the function of this protein in the organism and its putative connection to the electron transport chain to ferric iron.

Leucobacter chromiiresistens sp. nov., a chromate-resistant strain.

A Gram-positive, irregular rod-shaped, non-motile, yellow-pigmented bacterium, strain JG 31(T), was isolated in the course of identifying chromium-resistant soil bacteria. 16S rRNA gene sequence analysis of the isolated bacterium indicated its phylogenetic position within the genus Leucobacter. Binary 16S rRNA gene sequence alignments of the isolated bacterium with the 11 species of the genus recognized at the time of writing revealed sequence similarities of more than 97 % with Leucobacter alluvii (GenBank accession no: AM072820; 99.