Maltose-Enhanced Exopolysaccharide Synthesis of Lactiplantibacillus plantarum through CRP-like Protein

Abstract

Carbon sources alter the synthesis of exopolysaccharides (EPS) in Lactiplantibacillus plantarum. Maltose increased the EPS production of L. plantarum 163 6.5-fold. Subsequently, EPS production, transcriptome, and proteome were analyzed using glucose or maltose to further clarify the regulatory mechanism. A cAMP receptor protein (UniProtKB: F9UNI5) has been identified to control EPS synthesis in the presence of cAMP by binding to the EPS synthesis promoter Pcps4A‑J. Overexpression of the cAMP synthesis gene cyaA increased cAMP content and EPS production 4.5- and 2.2-fold, respectively. Furthermore, yogurt produced with L. plantarum 163-cyaA had a similar viscosity to that of commercial Greek yogurt; it had 20 and 83.7% greater viscosity than that produced with L. plantarum 163 with maltose and glucose, respectively. These findings indicated that L. plantarum 163-cyaA has potential applications in the production of functional fermented dairy products.

Glycosyltransferases Expression Changes in Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 Grown on Different Carbon Sources

“…The biological role of HoPs in Ln. strains is not sufficiently clear, though the existing hypothesis points out functions such as energy storage, environmental protection (adverse pH, desiccation, depredation), cell adhesion (oral cavity or intestinal tract), and cell communication in biofilms [14][15][16][17][18]. Moreover, despite the increasing evidence of the role of Ln.…”

“…mesenteroides strains demonstrated a decrease in GTFs activity when glucose or fructose are used instead of sucrose as a carbon source in aerobic cultures [21][22][23]. The presence of diverse mechanisms for the uptake of carbon sources, such as permeases and the involvement of the Phosphotransferase System (PTS) was made evident [18,23,24], and most conclusions indicated that sucrose is an atypical inducer for dextransucrase, at least in the case of Ln. mesenteroides NRRL B512F where the existence of post-transcriptional regulation was suggested [22].…”