First isolation of Brevibacterium sp. pigments in the rind of an industrial red-smear-ripened soft cheese

International audienceThe smear-ripened soft cheeses are characterised by a surface orange-red-brown colour, which has a microbial origin. For a long time, this colouration was mainly imputed to Brevibacterium linens. However, the latest published works, based on molecular biology, have shown a minor role for this bacterium. This study shows the results obtained with an industrial cheese named Vieux-Pané, which is characterised by the presence of carotenoids from Brevibacterium linens group at its surface. This demonstrates that, under certain conditions, the Brevibacterium linens group (Brevibacterium linens and Brevibacterium aurantiacum sp. nov.) is able to produce pigments and to colour cheeses effectively

Selection of genes showing a differential abundance between Day 1 and Day 14 and/or Day 14 and Day 31.

<p>The log2 fold change and the average number of reads (mean) are indicated only if the gene revealed a significant difference between the two ripening times (adjusted p-value < 0.05).</p><p>Selection of genes showing a differential abundance between Day 1 and Day 14 and/or Day 14 and Day 31.</p

Sequencing coverage (C) and percentage of genes (P) with at least an average of five uniquely mapped reads in the DNA-Seq dataset across the three replicates for each microbial genome during ripening.

<p>^aAA = <i>Arthrobacter arilaitensis</i>; BA = <i>Brevibacterium aurantiacum</i>; CC = <i>Corynebacterium casei</i>; DH = <i>Debaryomyces hansenii</i>; GC = <i>Geotrichum candidum</i>; HA = <i>Hafnia alvei</i>; KL = <i>Kluyveromyces lactis</i>; LL = <i>Lactococcus lactis</i>; SE = <i>Staphylococcus equorum</i></p><p>Sequencing coverage (C) and percentage of genes (P) with at least an average of five uniquely mapped reads in the DNA-Seq dataset across the three replicates for each microbial genome during ripening.</p

Protein degradation during surface-ripened cheese maturation.

<p>(A) Proteolysis and free amino acid concentration. Expression data observed for genes encoding proteases (B) and peptidases (C). Read numbers were normalized (according to the library size) to 50,000 reads per sampling day. SE: <i>Staphylococcus equorum</i>. BA: <i>Brevibacterium aurantiacum</i>. AA: <i>Arthrobacter arilaitensis</i>. HA: <i>Hafnia alvei</i>. CC: <i>Corynebacterium casei</i>. LL: <i>Lactococcus lactis</i>. KL: <i>Kluyveromyces lactis</i>. DH: <i>Debaryomyces hansenii</i>. GC: <i>Geotrichum candidum</i>.</p

Gene expression related to amino acid metabolism.

<p>For each pathway, the heatmap represents the expression dynamics over time (cumulative number of normalized reads per pathway) using a gray scale bar from 0 read in white to 500 reads in black. For seven pathways, histogram charts detail this dynamic per microbial species. CC: <i>Corynebacterium casei</i>, HA: <i>Hafnia alvei</i>, AA: <i>Arthrobacter arilaitensis</i>, BA: <i>Brevibacterium aurantiacum</i>, SE: <i>Staphylococcus equorum</i>, LL: <i>Lactococcus lactis</i>, KL: <i>Kluyveromyces lactis</i>, DH: <i>Debaryomyces hansenii</i>, GC: <i>Geotrichum candidum</i>.</p

Number of differentially expressed genes according to ripening time.

<p>Number of differentially expressed genes according to ripening time.</p