Production of Buttery-Odor Compounds and Transcriptome Response in Leuconostoc gelidum subsp. gasicomitatum LMG18811Tduring Growth on Various Carbon Sources

摘要: ABSTRACTLeuconostoc gelidumsubsp.gasicomitatumis a common spoilage bacterium in meat products packaged under oxygen-containing modified atmospheres. Buttery off-odors related to diacetyl/acetoin formation are frequently associated with the spoilage of these products. A whole-genome microarray study, together with gas chromatography (GC)-mass spectrometry (MS) analyses of the pathway end products, was performed to investigate the transcriptome response ofL. gelidumsubsp.gasicomitatumLMG18811Tgrowing on semidefined media containing glucose, ribose, or inosine, which are essential carbon sources in meat. Generally, the gene expression patterns with ribose and inosine were quite similar, indicating that catabolism of ribose and nucleosides is closely linked. Diacetyl/acetoin concentrations as high as 110 or 470 μM were measured when growth was based on inosine or ribose, respectively. The gene expression results for pyruvate metabolism (upregulation of α-acetolactate synthase, downregulation ofl-lactate dehydrogenase and pyruvate dehydrogenase) were as expected when diacetyl and acetoin were the end products. No diacetyl production (<7.5 μM) was detected with the glucose-containing medium, even though the cell counts of LMG18811Twas 6 or 10 times higher than that on inosine or ribose, respectively. Although glucose was the most effective carbon source for the growth ofL. gelidumsubsp.gasicomitatum, utilization of inosine and ribose resulted in the production of the unwanted buttery-odor compounds. These results increase our understanding of which compounds are likely to enhance the formation of buttery odors during meat spoilage caused byL. gelidumsubsp.gasicomitatum.