P96: Gene expression profiling of Corynebacterium glutamicum under anaerobic nitrate respiration

Corynebacterium glutamicum is a nonpathogenic high-GC gram-positive soil bacterium that has been widely used for industrial production of various amino acids and nucleic acids. A bioprocess using C. glutamicum cells based on its active fermentative metabolism under oxygen-deprived conditions has been recently developed for production of various compounds, lactate, succinate, and ethanol etc. Transcriptome and metabolome analyses were carried out to examine C. glutamicum response to oxygen deprivation, however, it should be noted that cellular growth is arrested under these conditions. C. glutamicum gene regulation in response to anaerobiosis at a genome-wide level remains largely obscure. It is only recently that C. glutamicum was shown to grow anaerobically, using nitrate as a terminal electron acceptor. In this study, we investigated a transcriptional profile of C. glutamicum during anaerobic growth in the presence of nitrate compared with that of aerobically growing cells using DNA microarray analysis. We noted differences in the expression of a number of genes involved in a variety of cellular functions, including carbon metabolism and respiratory electron transport chain. We particularly focused on the finding that induction of the SOS response, a DNA repair and damage tolerance system, was detected, and investigated its physiological role during anaerobic nitrate respiration in C. glutamicum. This work was partially supported by a grant from the New Energy and Industrial Technology Development Organization (NEDO).