In the current study, a significant amount of ulvan was extracted from Ulva lactuca collected from Alexandria coastline, Egypt, using a simple extraction method. According to the chemical analysis, the obtained polysaccharide content is estimated to be 36.50 g/100 g with a high sulfate content of 19.72%. Physio-chemically, the FTIR analysis confirmed the presence of sulfated groups attached to the carbohydrate backbone. The GC–MS results revealed the presence of various monosaccharides with relative abundances in the order: fucopyranose (22.09%) > L-rhamnose (18.17%) > L-fucose (17.46%) > rhamnopyranose (14.29%) > mannopyranose (8.59%) > α-D-glactopyranose (7.64%) > galactopyranose (6.14%) > β-arabinopyranose (5.62%). In addition, the SEM–EDX depicted an amorphous architecture with a majority wt% for the elements of C, O, and S. The partially purified ulvan demonstrated potent antimicrobial activity against some fish and human pathogenic microbes. The inhibition zone diameter ranged from 11 to 18 mm. On the other hand, the prepared ulvan-chitosan hydrogel significantly improved the antimicrobial activity as the inhibition zone diameter ranged from 12 to 20. Moreover, when compared to the controls, the extracted ulvan demonstrated anti-fouling properties and successfully disrupted the biofilm formed on a glass slide submerged in seawater.

Because of its safety, biological activities, and unique properties, exopolysaccharide (EPS) from lactic acid bacteria (LAB) has been developed as a potential biopolymer. A few studies have investigated the EPS produced by marine LAB. This study reports the wound healing activity of an EPS produced by a marine isolate identified as Lactiplantibacillus plantarum EI6, in addition to assessing L. plantarum EI6's probiotic properties. EI6 demonstrated promising antimicrobial activity against different pathogenic bacteria, as well as the ability to withstand stomach pH 3, tolerate 0.3% bile salt concentration, and exhibit no signs of hemolysis. Furthermore, EI6 was able to produce 270 mg/L of EPS upon growth for 48 h at 37°C in an MRS medium enriched with 1.0% of sucrose. The chemical features of the novel EI6-EPS were investigated: the UV-vis estimated a high carbohydrate content of ~91.5%, and the FTIR emphasized its polysaccharide nature by the characteristic hydroxyl, amide I, II, & III, and glycosidic linkage regions. The GC-MS and NMR analyses revealed the existence of five monosaccharides, namely, rhamnose, galactose, mannose, glucose, and arabinose, existing mainly in the pyranose form and linked together by α- and β-glycosidic linkages. EI6-EPS was found to be safe (IC50 > 100 μg/ml) and induced human skin fibroblasts (HSF) proliferation and migration. These findings imply that EI6 can be used as a safe source of bioactive polymer in wound care.

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Marsupenaeus japonicas FTIR Antimicrobial activity Chitin was extracted from the skeleton of Marsupenaeus japonicus shrimp shell waste with a yield of 27.7% of the net weight through three steps namely; deproteinization, decolourization and demineralization. After deacetylation process of extracted chitin, chitosan was produced and represented 55.1% of the extracted chitin. Scanning electron microscope and Fourier Transform Infrared spectroscopy (FTIR) analyses were conducted to characterize the obtained chitin and chitosan. The FTIR analysis revealed different absorption bands within 4000-400 cm-1 range; by comparison these bands were found to be similar to those of commercial chitin and chitosan and confirmed partial deacetylation in the produced chitosan. Moreover, the antimicrobial activity of commercial and extracted chitin and chitosan were examined against different pathogenic Gram positive, Gram negative bacteria and fungi using agar well diffusion test. Results showed that there was no significant difference p < 0.05 in the antimicrobial activity of the extracted compounds and commercial ones against test pathogens as the extracted compounds recorded inhibition zones ranged from 12 to 23 mm in diameter while the commercial compounds recorded inhibition zones of diameters ranged from 12 to 22 mm only; with Staphylococcus aureus ATCC 25923 being the most affected microbe with inhibition zone of 23 mm produced by extracted chitin, while the lowest zone of inhibition was recorded against Enterococcus faecalis ATCC 29212 with only 12 mm by commercial and extracted chitosan.