Variability of Bacterial Homopolysaccharide Production and Properties during Food Processing

Abstract

Various homopolysaccharides (HoPSs) can be produced by bacteria: α- and β-glucans, β-fructans and α-galactans, which are polymers of glucose, fructose and galactose, respectively. The synthesis of these compounds is catalyzed by glycosyltransferases (glycansucrases), which are able to transfer the monosaccharides in a specific substrate to the medium, which results in the growth of polysaccharide chains. The range of HoPS sizes is very large, from 104 to 109 Da, and mostly depends on the carbon source in the medium and the catalyzing enzyme. However, factors such as nitrogen nutrients, pH, water activity, temperature and duration of bacterial culture also impact the size and yield of production. The sequence of the enzyme influences the structure of the HoPS, by modulating the type of linkage between monomers, both for the linear chain and for the ramifications. HoPSs’ size and structure have an effect on rheological properties of some foods by their influence on viscosity index. As a consequence, the control of structural and environmental factors opens ways to guide the production of specific HoPS in foods by bacteria, either by in situ or ex situ production, but requires a better knowledge of HoPS production conditions.

Exopolysaccharides of Lactic Acid Bacteria: Production, Purification and Health Benefits towards Functional Food

“…Homopolysaccharides are largely constructed from sucrose, by the polymerization of glucose or fructose, and have been further divided into four subgroups: α-glucans, β-glucan, β-fructans and α-galactan [ 44 ]. Both glucan types consist solely of glucose, but their different linkages make it possible to further distinguish their structure.…”

“…The β-fructans contain units of fructose linked with either β-2,1 or β-2,6 and osidic bonds, which are divided into inulin-type (β-2,1) and levan (β-2,6). Finally, the less common β-galactan is comprised of galactose units linked with either β-1,3 or β-1,6 [ 44 ]. Both glucans, fructans and galactans are produced by LAB belonging to the genera of Lactobacillus , Streptococcus and Leuconostoc ( Figure 4 ) [ 34 ].…”

Bio_Fabricated Levan Polymer from Bacillus subtilis MZ292983.1 with Antibacterial, Antibiofilm, and Burn Healing Properties

“…Levansucrase accounts for at least 25% of the released reducing sugars during bacterial growth in the existence of sucrose [31]. In our study, both the amount of total soluble carbohydrates and total reducing sugars were determined and recorded as 90.28 ± 1.67 µg mg −1 and 290 µg mg −1 , respectively.…”

“…Commercial production and many industrial uses have sparked a lot of interest in levan due to its applications as a sweetener, gum, stabilizer, emulsifier, encapsulating agent, thickener, and an appropriate raw material for the manufacturing of green plastics. [31]. Many applications of levan have been documented in relation to its unique properties when compared to other polysaccharides.…”

The C-Terminal Domain of Liquorilactobacillus nagelii Dextransucrase Mediates the Production of Larger Dextrans Compared to Liquorilactobacillus hordei

“…HePS are produced intracellularly upon the use of nucleotide-activated sugar donors and are subsequently secreted by different pathways that mainly predetermine where the assembled polysaccharide will reside outside the cell, i.e., attached to the cell or released. Whereas the synthesis of HePS is rather complex, requiring several catalytic steps that are mediated by various enzymes [ 7 , 8 ], HoPS are often synthesized by only one enzyme, which is either attached to the cell surface or released into the surrounding milieu [ 9 , 10 ]. Belonging to this group of enzymes, glycoside hydrolase family 70 (GH70) enzymes represent a diverse group of enzymes that can produce large and often branched extracellular polysaccharides (EPS) on the basis of sucrose, starch or maltooligosaccharides [ 11 ].…”