Catabolite responsive element deficiency ofxyloperon resulting in carbon catabolite derepression inLactobacillus fermentum1001

Abstract

Lactobacillus fermentum 1001 is a potential candidate as a CCR-absent cell factory to transform biomass to high-value-added products. P1x was provided for engineering LAB to enhance fermentation efficiency by avoiding CCR.

The local transcriptional regulators SacR1 and SacR2 act as repressors of fructooligosaccharides metabolism in Lactobacillus plantarum

“…The CCR in response to glucose may have been predominant in the context of dual regulation, whereas the effects of local regulators could not be observed [18]. As the global regulation mechanism of CCR is generally triggered by glucose [14], we used ribose, a non-preferred substrate, as an alternative carbon source to verify the roles of SacR1 and SacR2 through RT-qPCR experiments. Notably, both FOS metabolism-related clusters were signi cantly activated by FOS (versus ribose), whereas this effect vanished after SacR1 and SacR2 inactivation.…”

“…In bacteria, the uptake and consumption of different carbohydrates are tightly regulated, as the simultaneous utilization of all accessible sugars would be energetically ine cient [13]. The presence of preferred carbon sources prevents the utilization of secondary substrates via a phenomenon called carbon catabolite repression (CCR) [14,15]. CCR, a complex regulatory phenomenon, is frequently mediated by several mechanisms [16] that either affect the synthesis of catabolic enzymes via global or speci c regulators or inhibit the uptake of a carbon source and, consequently, the formation of the corresponding inducer [17].…”

The local transcriptional regulators SacR1 and SacR2 act as repressors of fructooligosaccharides metabolism in Lactobacillus plantarum

“…The CCR in response to glucose may have been predominant in the context of dual regulation, whereas the effects of local regulators could not be observed [18]. As the global regulation mechanism of CCR is generally triggered by glucose [14], we used ribose, a non- The regulation of locally regulated gene transcription involves the binding of specific regulators to binding sites on the target genes [25,26]. However, potential SacR1 and SacR2 binding sequences had not previously been clarified in the two FOS metabolism-related clusters in L. plantarum.…”

“…In bacteria, the uptake and consumption of different carbohydrates are tightly regulated, as the simultaneous utilization of all accessible sugars would be energetically inefficient [13]. The presence of preferred carbon sources prevents the utilization of secondary substrates via a phenomenon called carbon catabolite repression (CCR) [14,15]. CCR, a complex regulatory phenomenon, is frequently mediated by several mechanisms [16] that either affect the synthesis of catabolic enzymes via global or specific regulators or inhibit the uptake of a carbon source and, consequently, the formation of the corresponding inducer [17].…”

The local transcriptional regulators SacR1 and SacR2 act as repressors of fructooligosaccharides metabolism in Lactobacillus plantarum

“…In bacteria, the uptake and assimilation of different carbohydrates are tightly regulated, as the simultaneous utilization of all accessible sugars would be energetically inefficient [ 13 ]. The presence of preferred carbon sources prevents the utilization of secondary substrates via a phenomenon called carbon catabolite repression (CCR) [ 14 , 15 ]. CCR, a complex regulatory phenomenon, is frequently mediated by several mechanisms [ 16 ] that either affect the synthesis of catabolic enzymes via global or specific regulators or inhibit the uptake of a carbon source and, consequently, the formation of the corresponding inducer [ 17 ].…”