Transcriptome analysis of probiotic Lactobacillus casei Zhang during fermentation in soymilk

Abstract

Lactobacillus casei Zhang is a widely recognized probiotic bacterium, which is being commercially used in China. To study the gene expression dynamics of L. casei Zhang during fermentation in soymilk, a whole genome microarray was used to screen for diVerentially expressed genes when grown to the lag phase, the late logarithmic phase, and the stationary phase. Comparisons of diVerent transcripts next to each other revealed 162 and 63 signiWcantly induced genes in the late logarithmic phase and stationary phase, of which the expression was at least threefold up-regulated and down-regulated, respectively. Approximately 38.4% of the up-regulated genes were associated with amino acid transport and metabolism notably for histidine and lysine biosynthesis, followed by genes/ gene clusters involved in carbohydrate transport and metabolism, lipid transport and metabolism, and inorganic ion transport and metabolism. The analysis results suggest a complex stimulatory eVect of soymilk-based ecosystem on the L. casei Zhang growth. On the other hand, it provides the very Wrst insight into the molecular mechanism of L. casei strain for how it will adapt to the protein-rich environment. © Society for Industrial Microbiology 2011.