Anaerobic growth and potential for amino acid production by nitrate respiration in Corynebacterium glutamicum

• Published in: Applied microbiology and biotechnology Vol. 75; no. 5; pp. 1173 - 1182
• Main Authors: Takeno, Seiki, Ohnishi, Junko, Komatsu, Tomoha, Masaki, Tatsuya, Sen, Kikuo, Ikeda, Masato
• Format: Journal Article
• Language: English
• Published: Berlin Berlin/Heidelberg : Springer-Verlag 01.07.2007; Springer; Springer Nature B.V
• Subjects: Amino acid production; Amino acids; Amino Acids - biosynthesis; Bacteria, Anaerobic - metabolism; Biological and medical sciences; Biotechnology; Carbon; Corynebacterium glutamicum; Corynebacterium glutamicum - metabolism; E coli; Electrons; Enzymes; Fermentation; Fundamental and applied biological sciences. Psychology; Genes; Genomes; Metabolism; Mutation; nitrate reductase; Nitrate respiration; Nitrates; Nitrates - metabolism; Oxygen Consumption - physiology; Oxygen limitation; Respiration; Taxonomy; Tuberculosis; Anaerobe; Growth; Aminoacid; Corynebacterium glutamicum; Production; Bacteria; Actinomycetes; Corynebacteriaceae; Nitrates; Respiration
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-007-0926-8

Oxygen limitation is a crucial problem in amino acid fermentation by Corynebacterium glutamicum. Toward this subject, our study was initiated by analysis of the oxygen-requiring properties of C. glutamicum, generally regarded as a strict aerobe. This organism formed colonies on agar plates up to relatively low oxygen concentrations (0.5% O₂), while no visible colonies were formed in the absence of O₂. However, in the presence of nitrate ( [graphic removed] ), the organism exhibited limited growth anaerobically with production of nitrite ( [graphic removed] ), indicating that C. glutamicum can use nitrate as a final electron acceptor. Assays of cell extracts from aerobic and hypoxic cultures yielded comparable nitrate reductase activities, irrespective of nitrate levels. Genome analysis revealed a narK2GHJI cluster potentially relevant to nitrate reductase and transport. Disruptions of narG and narJ abolished the nitrate-dependent anaerobic growth with the loss of nitrate reductase activity. Disruption of the putative nitrate/nitrite antiporter gene narK2 did not affect the enzyme activity but impaired the anaerobic growth. These indicate that this locus is responsible for nitrate respiration. Agar piece assays using l-lysine- and l-arginine-producing strains showed that production of both amino acids occurred anaerobically by nitrate respiration, indicating the potential of C. glutamicum for anaerobic amino acid production.