Characterization of Pediococcus ethanolidurans CUPV141: A β-D-glucan- and Heteropolysaccharide-Producing Bacterium

Abstract

Pediococcus ethanolidurans CUPV141 is an exopolysaccharide (EPS)-producing lactic acid bacterium, first isolated from Basque Country cider (Spain). Physicochemical analysis of the EPS synthesized by the bacterium revealed that CUPV141 produces mostly a homopolysaccharide (HoPS), characterized as a 2-substituted (1,3)-β-D-glucan, together with a small quantity of a heteropolysaccharide (HePS) composed of glucose, galactose, glucosamine, and glycerol-3-phosphate, this being the first Pediococcus strain described to produce this kind of polymer. On the contrary, an isogenic strain CUPV141NR, generated by chemical mutagenesis of CUPV141, produced the HePS as the main extracellular polysaccharide and a barely detectable amount of 2-substituted (1,3)-β-D-glucan. This HoPS is synthesized by the transmembrane GTF glycosyltransferase (GTF), encoded by the gtf gene, which has been previously reported to be located in the pPP2 plasmid of the Pediococcus parvulus 2.6 strain. Southern blot hybridization revealed that in CUPV141 the gtf gene is located in a plasmid designated as pPE3, whose molecular mass (34.4 kbp) is different from that of pPP2 (24.5 kbp). Analysis of the influence of the EPS on the ability of the producing bacteria to adhere to the eukaryotic Caco-2 cells revealed higher affinity for the human enterocytes of CUPV141NR compared to that of CUPV141. This result indicates that, in contrast to the 2.6 strain, the presence of the HoPS does not potentiate the binding ability of P. ethanolidurans. Moreover, it supports that the phosphate-containing bacterial HePS improved the interaction between P. ethanolidurans and the eukaryotic cells.

Proteomic Analysis Reveals Enzymes for β-D-Glucan Formation and Degradation in Levilactobacillus brevis TMW 1.2112

“…The transmembrane β-1,3 glucan synthase (GT2 family) is described as the key enzyme in the bacterial β-glucan biosynthesis [ 15 , 41 , 46 , 48 ]. The GT2 family comprises thousands of sequences with at least 12 distinct GT functions, making a functional prediction by homology difficult [ 82 ]. However, Llamas-Arriba et al (2018) compared the nucleotide sequences of 13 β-1,3 glucan synthases of Pediococcus spp., Oenococcus oeni , and Lactobacillus spp., including L. brevis TMW 1.2112 (AZI09_12770).…”

Relationship of Gene-Structure–Antioxidant Ability of Exopolysaccharides Derived from Lactic Acid Bacteria: A Review

“…For instance, the initiating glycosyltransferase is phosphorylated by tyrosine kinase and results in the formation of phosphate bonds between the first hexose-1-phosphate carrier of the repeating units and the undecyl phosphate lipid carrier anchored on the membrane, thereby catalyzing the first step of the synthesis of HePS. Other GTFs sequentially transfer nucleotides to the growing chain and synthesize repeating units . The EPS assembly enzymes such as GTFs and polymerases link the monomer of polymer chain to the undecaprenol diphosphate anchor (C55) at the inner membrane; the polymers are subsequently transported to the cytoplasmic membrane by Wzx proteins .…”

Exopolysaccharides Producing Lactic Acid Bacteria in Wine and Other Fermented Beverages: For Better or for Worse?

“…For example, certain strains of O. oeni isolated from wine or cider produce both dextran (α-1,6-α-1,3 glucan), levan (β-2,6 fructan), β-glucan and heteropolysaccharides composed of galactose, glucose and rhamnose [ 35 ]. Pediococcus ethanolidurans isolated from Basque cider also produces both ropy β-glucan and a heteropolysaccharide composed of glucose, galactose, glucosamine and glycerol-3-phosphate [ 24 ].…”

“…The Wzy-dependent pathway leads to the release of at most 250 mg/L of heteropolysaccharide in O. oeni and about 50 mg/L in P. ethanolidurans [ 24 , 35 , 44 ]. Furthermore, depending on the bacterial strain and the growth conditions, the concentration of β-glucan can vary between 10 and 250 mg/L [ 18 , 19 , 44 ].…”

“…In wine and cider LAB, some of these genes seem extremely mobile, in particular the gtf gene, associated with the synthesis of the β-glucan causing wine or cider ropiness. In fact, it is carried by at least four different plasmids within the genus Pediococcus [ 17 , 23 , 24 , 63 ], and it is chromosomic (but inserted in a phage remnant or even in a prophage) in O. oeni [ 18 , 35 ]. Despite the high number of genetic locations, the gene is more than 95% conserved between the bacterial species capable of producing the ropy β-glucan: Lb.…”