Codium bernabei is a green alga that grows on Chilean coasts. The composition of its structural polysaccharides is still unknown. Hence, the aim of this work is to isolate and characterize the hot water extracted polysaccharide fractions. For this purpose, the water extracts were further precipitated in alcohol (TPs) and acid media (APs), respectively. Both fractions were characterized using different physicochemical techniques such as GC-MS, GPC, FTIR, TGA, and SEM. It is confirmed that the extracted fractions are mainly made of sulfated galactan unit, with a degree of sulfation of 19.3% (TPs) and 17.4% (ATs) and a protein content of 3.5% in APs and 15.6% in TPs. Other neutral sugars such as xylose, glucose, galactose, fucose, mannose, and arabinose were found in a molar ratio (0.05:0.6:1.0:0.02:0.14:0.11) for TPs and (0.05:0.31:1.0:0.03:0.1:0.13) for ATs. The molecular weight of the polysaccharide samples was lower than 20 kDa. Both polysaccharides were thermally stable (Tonset > 190 °C) and showed antioxidant activity according to the ABTS^•+ and DPPH tests, where TPs fractions had higher scavenging activity (35%) compared to the APs fractions. The PT and APTTS assays were used to measure the anticoagulant activity of the polysaccharide fractions. In general, the PT activity of the TPs and APs was not different from normal plasma values. The exception was the TPs treatment at 1000 µg mL⁻¹ concentration. The APTTS test revealed that clotting time for both polysaccharides was prolonged regarding normal values at 1000 µg mL⁻¹. Finally, the antitumor test in colorectal carcinoma (HTC-116) cell line, breast cancer (MCF-7) and human leukemia (HL-60) cell lines showed the cytotoxic effect of TPs and APs. Those results suggest the potential biotechnological application of sulfate galactan polysaccharides isolated from a Chilean marine resource.

Plastic food packaging causes massive pollution in the environment via resource extraction, gas emissions, and the enduring plastic waste accumulation. Hence, it is of crucial importance to discover sustainable alternatives in order to protect ecosystems and conserve precious resources. Recently, seaweed has been emerging as a promising sustainable solution to plastic pollution. Seaweed is a fast-growing marine plant that is abundant in tropical coastlines and requires minimal resources to cultivate. In addition, seaweed is rich in valuable polysaccharides such as alginate, fucoidan, carrageenan, agar, and ulva, which can be extracted and processed into biodegradable films, coatings, and wraps. This ability allows the creation of an alternative to plastic food packages that are completely biodegradable, made from renewable resources, and do not linger in landfills or oceans for centuries. In this context, this review discusses the main classification of seaweed, their production and abundance in the world, and provides a summary of seaweed-based materials developed in the last 2–5 years for potential usage in the food packaging sector.

Fungal polysaccharides possess a broad biological activity, including cytotoxic and antioxidant activities. This work aimed to evaluate the cytotoxic and antioxidant activity of the acidic polysaccharides of Phylloporia boldo strain (named PBAP40). Cytotoxic activity of polysaccharide was evaluated determining the viability of three tumor cell lines by MTT assay. The effect of acidic polysaccharide on the cell cycle of HL-60 cell line was evaluated by flow cytometry, and the antioxidant activity was determined by DPPH and ABTS assays. PBAP40 showed cytotoxic effects in tumor cell lines. Results suggest that P. boldo acidic polysaccharides arrested tumor cells in the cell cycle Sub G1 phase. The acidic polysaccharides of PBAP40 strain were not cytotoxic for the non-tumor cell line. PBAP40 also showed excellent antioxidant activity. The FT-IR analysis of the acidic polysaccharides indicated the presence of glucans bearing α- and β- type glycosidic bonds. Graphical Abstract

The invasive diatom Didymosphenia geminata (Lyngbye) M. Schmidt has received considerable attention in recent years due to its rapid geographic expansion and massive proliferation, which have altered habitat availability for benthic species and triggered negative effects on stream ecosystems. We evaluated the changes in the community structure of phytobenthos caused by the temporal variation in D. geminata coverage, in addition to the environmental variables correlated with the temporal variation of this invasive microalga in the Andean sector of the Biobio River basin, Chile. Environmental parameters were measured during the austral summer of 2014–2015, when phytobenthos samples were collected and used to develop a relative abundance matrix of taxa by calculating species richness and Shannon diversity. Multivariate techniques were used to establish the relationships among environmental variables, including D. geminata coverage, and the phytobenthic community. Massive proliferation of D. geminata occurs during summer (December–January). According to multiple regression analysis, electrical conductivity, temperature and total phosphorus were the variables that best explained the variation in D. geminata coverage. When D. geminata coverage was over 50%, phytobenthic species richness was significantly higher than at the uninvaded site, without a significant change in Shannon diversity. In addition, the % coverage of this invasive microalga and total phosphorus concentration were variables that differentiated phytobenthic communities among the study sites. Environmental factors such as conductivity, temperature and total phosphorus concentration influenced the temporal variability of D. geminata mats. In addition, the massive growth of this invasive diatom caused a higher species richness without altering Shannon diversity. Our results suggest that the spatio-temporal variability of D. geminata correlated with environmental variables will help predict the habitat suitability of this alga in other Andean rivers and allow a better understanding of ecological habitat alterations.