Transcriptome response of Lactobacillus sakei to olive oil and tributyrin environments

Lactobacillus sakei is a ubiquitous, heterofermentative, lactic acid bacterium that is frequently used in industrial-scale cultures. To investigate its adaptation to a fat or ester environment, whole-genome DNA microarrays were used to analyze the expression of genes related to the growth of L. sakei strain La22 that was cultured on olive oil- or tributyrin-supplemented De Man, Rogosa, and Sharpe (MRS) medium. We detected 427 genes that were differentially expressed relative to the non-supplemented control. The up-regulated genes were mainly related to lipid or nucleotide metabolism and included genes encoding a putative lipase/esterase and a putative extracellular lysophospholipase precursor. Genes that were down-regulated in the presence of olive oil or tributyrin were associated with carbohydrate or amino acid metabolism. Genes responsible for cell envelope and cellular processes and adaptation to atypical conditions showed varied expression on olive oil- or tributyrin-supplemented media compared with that on MRS medium alone, with some L. sakei genes involved in stress responses displaying increased expression.