Physiology and global gene expression of a Corynebacterium glutamicum ΔF(1)F(O)-ATP synthase mutant devoid of oxidative phosphorylation.

A mutant of Corynebacterium glutamicum ATCC 13032 with a deletion of the atpBEFHAGDC genes encoding F(1)F(O)-ATP synthase was characterized. Whereas no growth was observed with acetate as sole carbon source, the ΔF(1)F(O) mutant reached 47% of the growth rate and 65% of the biomass of the wild type during shake-flask cultivation in glucose minimal medium. Initially, the mutant strain showed a strongly increased glucose uptake rate accompanied by a high oxygen consumption rate and pyruvate secretion into the medium.

Osmotic stress response in C. glutamicum: impact of channel- and transporter-mediated potassium accumulation.

Potassium accumulation is an essential aspect of bacterial response to diverse stress situations; consequently its uptake plays a pivotal role. Here, we show that the Gram-positive soil bacterium Corynebacterium glutamicum which is employed for the large-scale industrial production of amino acids requires potassium under conditions of ionic and non-ionic osmotic stress. Besides the accumulation of high concentrations of potassium contributing significantly to the osmotic potential of the cytoplasm, we demonstrate that glutamate is not the counter ion for potassium under these conditions.

Impact of improved potassium accumulation on pH homeostasis, membrane potential adjustment and survival of Corynebacterium glutamicum.

Metal ion uptake is crucial for all living cells and an essential part of cellular bioenergetic homeostasis. In this study the uptake and the impact of the most abundant internal cation, potassium, were investigated in Actinobacteria, a group of high G+C Gram-positives with a number of prominent biotechnologically and medically important members. Genome analyses revealed a variety of different potassium uptake systems in this monophyletic group ranging from potassium channels common in virtually all Actinobacteria to different active carriers that were present predominantly in pathogenic members able to cope with various stress conditions.

Functional genomics of pH homeostasis in Corynebacterium glutamicum revealed novel links between pH response, oxidative stress, iron homeostasis and methionine synthesis.

Background: The maintenance of internal pH in bacterial cells is challenged by natural stress conditions, during host infection or in biotechnological production processes. Comprehensive transcriptomic and proteomic analyses has been conducted in several bacterial model systems, yet questions remain as to the mechanisms of pH homeostasis.

Results: Here we present the comprehensive analysis of pH homeostasis in C.

Potassium transport in corynebacterium glutamicum is facilitated by the putative channel protein CglK, which is essential for pH homeostasis and growth at acidic pH.

We studied the requirement for potassium and for potassium transport activity for the biotechnologically important bacterium Corynebacterium glutamicum, which is used for large-scale production of amino acids. Different from many other bacteria, at alkaline or neutral pH, C. glutamicum is able to grow without the addition of potassium, resulting in very low cytoplasmic potassium concentrations.