Andrea Michel Livres

Corynebacterium glutamicum can grow anaerobically using nitrate as an electron acceptor, but low cell densities are achieved due to toxic nitrite. While it is metabolically active without oxygen, producing lactate, succinate, and acetate from glucose, its fermentative anaerobic growth had not been previously described. This study investigated C. glutamicum's potential for fermentative growth and amino acid production under anaerobic conditions. Results showed that the wild type could grow anaerobically in minimal medium with glucose, fructose, sucrose, and ribose, achieving optical densities of 1.9 (sucrose), 2.2 (glucose), and 2.7 (fructose and ribose). However, it could not utilize gluconate, pyruvate, lactate, acetate, or propionate. Growth experiments indicated energy limitation as a factor in poor anaerobic growth, and amino acid production (lysine, leucine, valine) was not feasible under tested conditions. The addition of peptides improved anaerobic growth significantly, allowing the cells to conserve energy for essential processes. A mutant lacking acetate formation genes achieved higher cell densities (OD600 = 16.8) and produced 64% less acetate than the wild type. Additionally, the pH tolerance range of C. glutamicum was notably reduced under anaerobic conditions, with slower pH homeostasis observed, as the respiratory chain's efficiency in expelling protons was compromised.

Im Februar 2003 startete die damals 31-jährige Andrea Michel zu ihrer Solo-Überquerung des Skandinavischen Gebirges. Von Grövelsjön bis Treriksröset wanderte die zähe Schweizerin mit Skiern, Pulka und Zelt ausgerüstet über den schwedischen Teil des Gebirges. Nach 62 Tagen erreichte sie als erste Frau, die diese 1200 km lange Wanderung alleine unternommen hat, ihr Ziel. In ihrem spannenden Expeditionstagebuch schildert die Abenteurerin ihre Erlebnisse in der Wildnis und Einsamkeit Schwedens und lässt den Leser teilhaben an ihren unzähligen herrlichen Erlebnissen draussen in der Natur, den Begegnungen mit Einheimischen, aber auch an Momenten, wo sie sich mit Schneestürmen und anderen Gefahren konfrontiert sah.