# Marine microalgae Biomolecules and Their Adhesion Capacity to _Salmonella enterica_ sv. Typhimurium
## 4 Discussion  
Generally, polysaccharides, cell wall constituents, or storage carbohydrates produced by microalgae are mainly composed of glucose and are called glucans. Their glycosidic linkages vary among the families, classes, and divisions to which they belong. In the happophytes and diatoms, the common storage polysaccharides are (1\(\rightarrow\)3)- and/or (1\(\rightarrow\)3),(1\(\rightarrow\)6)-\(\beta\)-glucans [48]. In happophytes, storage \(\beta\)-glucans have been investigated only in a few species. Polysaccharides from _Isochrysis galbana_, _Pleurochrysis happonemifera_, and _Emilania huxleyi_, belonging  
Figure 6: Number of _Salmonella_ Typhimurium attached to wells coated with microalgal extracts in the adhesion assay. Each bar (CFU \(\pm\) SD) represents the average of three replicates from three independent in vitro assays according to the fitted equations (\(n=9\)). Different letters indicate statistical differences (Tukey’s test, \(p<0.05\)). to class Coccolithophyceaeae, showed a highly branched (1\(\to\)3),(1\(\to\)6)-\(\beta\)-p-glucan with a (1\(\to\)6)-linked \(\beta\)-d-Glc\(p\) backbone substituted at O-3 by single glucose units or rather short (up to tetrasaccharide) glucooligosaccharide chains [39; 49; 50], while the polysaccharide from _Phaeocystis globose_ was described as a (1\(\to\)3)-linked \(\beta\)-p-glucan substituted at O-6 by glucose residues [51]. In the present research, the glucans isolated from _P. gyrans_ and _P. luther_ showed similar structures as expected for species of the same genus. Linear (1\(\to\)3)-linked \(\beta\)-glucans were identified in the cold-water-insoluble fraction, while highly branched \(\beta\)-glucans, constituted by a (1\(\to\)3)-linked backbone with substitution at O-6, remained in the cold-water-soluble fraction of both species. In addition to carbohydrates, proteins and lipids are abundant in most haptophytes. [PERSON] et al. [52] and [PERSON] et al. [7] found 24.2%-32.5% and 33.8%-54.3% protein contents in Coccolithophyceaeae and Pavlovophyceae species, respectively. Similar contents were found in the alkaline fractions obtained in this research (30.0%-49.1%). In these fractions, we also identified the glycosides SQG and DGG, as well as free fatty acids. The disruption process of the algal cell wall via the alkali treatment and high temperature used in this research saponified the native acylated forms, namely SQDG (sulfoquinovosyldiacylglycerol), DGDG (digalactosyldiacy|glycerol), and TAG (triacy|glycerol), generating water-soluble fragments, such as SQG, DGG, and sodium salts of fatty acids [42]. These molecules may interact with proteins, forming stable complexes not eliminated during the dialysis process [53]. Among lipids, the major lipid classes for _P. Pavlov_ species are TAG and glycolipids. [PERSON] and [PERSON] [54] reported the following for _P. luther_: 40% TAG, 25% MGDG (monogalactosyldiacy|glycerol), 10% SQDG, 8% DGDG, and 6% betaine lipids; [PERSON] and [PERSON] [55] also reported 42% TAG, 19% MGDG, 12% DGDG, 9% SQDG, 6% DOTA (diacylglycerol| hydroxymethyl-N,N,N-trimethyl-\(\beta\)-alanine), and 5% DGCC (diacylglycerol| carboxyhydroymethylcholine) for the same species. TAGs are neutral lipids mainly stored in vacuoles within the microalgal cell, while galactolipids and sulfolipids are constituents of chloroplast and extra plastid membranes, respectively [55; 56]. Developing alternatives to antibiotics is especially challenging in the area of intestinal infection prevention. The anti-adherence strategy using analog receptors has gained increasing importance. Analog receptors resemble host intestinal receptors and act as decoys via bacteria adsorption, interrupting the adherence process. In this study, an in vitro model was utilized to evaluate the ability of microalgal extracts to specifically adhere _Salmonella_ Typhimurium acting as analog receptor Fractions with an adhesion capacity were chemically distinct, indicating the presence of different bioactive molecules.