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This study focused on seaweed-based biomembrane development. The physical, mechanical, thermal, and biological properties of the fabricated films with different combinations of materials, such as agar, chitosan, poly(vinyl) alcohol (PVA), and quercetin, were characterized. The surface morphology of the films was analyzed using SEM. The maximum tensile strength (53.11 N/mm 2 ), elongation at break (3.42%), and Young's modulus (15.52) of the biomembrane were recorded for the agar + chitosan combination. FT-Raman analysis confirmed the functional groups shift between the biopolymer and plasticizer used in this study. TG-DSC analysis of the biomembranes revealed a T g in the range of 92.80°C-115°C. The maximum antioxidant activity was reported for quercetin (58.62%), and the maximum antimicrobial activity was observed for the chitosan and quercetin compounds against E. coli. A minimum hemolysis of 0.95% was achieved for the combination of agar + quercetin (AQ), agar + PEG (APE), Gracilaria corticata extract + PVA + quercetin (GCPQ) and agar + chitosan (AC) biomembranes. The minimum cytotoxicity of the biomembrane was 62.51% and 63.87% for Gracilaria corticata extract + PVA + quercetin (GCPQ), and agar + PVA, respectively. The proposed biomembrane films were found to be suitable for biomedical and packaging applications., (© 2024 Wiley Periodicals LLC.)

The meiofaunal diversity is used as an indicator to assess the complex and diverse impacts on the coastal environment during the natural calamities. The present study evaluates the effects of Mandous cyclone on ecologically two different stations, Pattinampakkam beach and Adyar estuary, which are located on Chennai coast, Tamil Nadu, India. The impact of the Mandous cyclone on physico-chemical parameters and meiobenthic faunal composition was investigated during, prior to, and after the cyclone. Thirty-nine species of meiofauna belonging to 15 taxa were recorded in both the stations. Nematoda, Oligochaeta and Harpacticoida taxa occurred with higher diversity and abundance than other meiofaunal taxa. Among these taxa, Polygastrophora sp. of Nematoda, Grania pusilla of Oligochaeta, and Arenosetella indica of Harpacticoida were the predominant species recorded during the study period. There was a prominent decline in the population density of meiofauna due to the Mandous cyclone, and thereafter, it took three weeks for recolonization and restoration to normalcy. Statistically, significant impact of the Mandous cyclone on the diversity, density, and evenness of the meiofaunal community with abiotic factors were observed through the Ecological indices and Canonical Correspondence Analysis. The Mandous cyclone assessment with special emphasis on meiofaunal communities allowed to fill the gap with knowledge regarding the diversity, abundance, composition, and distribution of meiofauna between pre- and post-Mandous cyclone, which helped in understanding the physico-chemical changes and response of meiofauna in a sandy beach and estuary., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, Haematococcus pluvialis and Coelastrella saipanensis were evaluated for heterotrophic nutrition potential in dairy waste medium by blocking the PSII using DCMU. The study was done by four sets of experiments. In the first set, in the different concentrations DCMU-treatments, 20μL showed pronounced effect in H. pluvialis and C. saipanensis as 89 % and 83% decrease in cells (>30 and > 250 cells/mL) compared to control (536 ± 12.35 × 10 4 and 1167 ± 15.35 × 10 4  cells/mL, respectively). Damage to the PS II by DCMU interrupted the growth, which in turn produced a significant drop in the number of cells. In the second round of experiment, growth of algae in various dairy waste concentrations suggest that dairy wastewater (DWW) provides enough nutrients to produce 35.71 % and 64.74 % more cells in H. pluvialis and C. saipanensis, respectively compared to the control. In the third set, high DCMU concentration was added to microalgae cultures in DWW to assess the heterotrophic nutrition potential. Growth in cell number 34.4 ± 19 and 617.46 ± 60.44 cells/mL was recorded in H. pluvialis and C. saipanensis when grown control medium whereas addition of DCMU reduced the cell number to 1.53 ± 0.75 and 55.13 ± 0.75 cells/mL on 15 th day, respectively. This shows cells in cultures treated with DCMU reveal that algae can sustain their metabolic activity by utilizing the nutrients of dairy waste inhibiting photosystem. Fourth round of experiments found that microalgae could resume their growth and productivity by adapting to heterotrophic nutritional behaviour when DCMU given in mild dose at different time interval. This study conclude as C. saipanensis grows more readily by absorbing dairy waste nutrients than H. pluvialis. Therefore, C. saipanensis is an excellent choice for wastewater treatment through sustainable environmentally benign process after scale-up investigation. These results provide useful information to advance to molecular study for measuring microalgae's capability for bioremediation application., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Kulanthaiyesu Arunkumar reports financial support was provided by Central University of Kerala. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Carrageenan is an emerging biopolymer for wound healing and regenerative applications. In this study, reduced graphene oxide (rGO) and hydroxyapatite (HAp) nano-composites infused carrageenan bioactive membrane was fabricated. Here, hydroxyapatite was synthesized from cuttlefish bone (CF-HAp) and its properties were compared with that of chemically synthesized HAp. Crystalline Ca 5 (PO 4 ) 3 (OH) and Ca 3 (PO 4 ) 2 ) phases were obtained in cuttlefish bone derived HAp. Reduced graphene oxide was synthesized and composites were prepared with chemical HAp and CF-HAp. FT-IR spectral analysis showed the imprints of hydroxyapatite on the membrane and also nano-structured particles were evident through morphological estimations that confirm the distribution of nano-particles on the carrageenan membrane. Nano-particulates infused carrageenan membrane showed the maximum tensile strength, in which graphene incorporated carrageenan bioactive membrane showed highest stability of 15.26 MPa. The contact angle of chemical HAp infused carrageenan membrane (CAR-HAp) showed more hydrophilic in nature (48.63° ± 7.47°) compared to control (61.77° ± 1.28°). Bio-compatibility features enunciate the optimal compatibility of fabricated bioactive membrane with fibroblast cell line; simultaneously, CAR-rGO-CF-HAp showed tremendous wound healing behavior with zebrafish model. Hence, fabricated bioactive membrane with the infusion of rGO- hydroxyapatite derived from cuttlefish bone was found to be a versatile biopolymer membrane for wound healing application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Plastic disposal and their degraded products in the environment are global concern due to its adverse effects and persistence in nature. To overcome plastic pollution and its impacts on environment, a sustainable bioplastic production using renewable feedstock's, such as algae, are envisioned. In this review, the production of polymer precursors such as polylactic acid, polyhydroxybutyrates, polyhydroxyalkanoates, agar, carrageenan and alginate from microalgae and macroalgae through direct conversion and fermentation routes are summarized and discussed. The direct conversion of algal biopolymers without any bioprocess (whole algal biomass used emphasizing zero waste discharge concept) favours economic feasibility. Whereas indirect method uses conversion of algal polymers to monomers after pretreatment followed by bioplastic precursor production by fermentation are emphasized. This review paper also outlines the current state of technological developments in the field of algae-based bioplastic, both in industry and in research, and highlights the creation of novel solutions for green bioplastic production employing algal polymers. Finally, the cost economics of the bioplastic production using algal biopolymers are clearly mentioned with future directions of next level bioplastic production. In this review study, the cost estimation was given at laboratory level bioplastic production using casting methods. Further development of bioplastics at pilot scale level may give clear economic feasibility of production at industry. Here, in this review, we emphasized the overview of algal biopolymers for different bioplastic product development and its economic value and also current industries involved in bioplastic production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

In the present study, the whole seaweed from Kappaphycus alvarezii (containing carrageenan) was used for preparation of bio-nanocomposite films by blending with metal oxide nanoparticles such as zinc oxide (ZnONPs), cupric oxide (CuONPs) and silicon dioxide (SiO 2 NPs) for multiple applications, and their properties were compared with standard refined κ-Carrageenan (commercial grade). Simultaneously, the antibacterial activity and biodegradation profile of the prepared bio-nanocomposite film were also studied. The incorporation of nanoparticles into the bioplastic film matrices altered the surface morphology, increased the roughness and significantly (p < 0.05) reduced the UV transmittance, water uptake ratio (WUR), moisture content and solubility in both standard carrageenan-based bio-nanocomposite films (CBF) and Kappaphycus- based bio-nanocomposite films (KBF) compared to control. The average roughness (Ra) of KBF increased compared to CBF; however, CBF showed better tensile strength compared to KBF. Both KBF and CBF loaded with nanoparticles exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli. However, KBF performed better compared to CBF. Antimicrobial effect of nanoparticles delayed the degradation of the bio-nanocomposite films. The present study proposes that the whole seaweed (Kappaphycus alvarezii) can be used directly for multiple industrial applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Over the past years, polysaccharide-based scaffolds have emerged as the most promising material for tissue engineering. In the present study, carrageenan, an injectable scaffold has been used owing to its advantage and superior property. Cissus quadrangularis, a natural agent was incorporated into the carrageenan scaffold. Therefore, the present study aimed to assess the antioxidant activity and biocompatibility of this novel material., Methods: The present in vitro study comprised of four study groups each constituting a sample of 15 with a total sample size of sixty (n = 60). The carrageenan hydrogel devoid of Cissus quadrangularis acted as the control group (Group-I). Based on the concentration of aqueous extract of Cissus quadrangularis (10% w/v, 20% w/v and 30% w/v) in carrageenan hydrogel, respective study groups namely II, III and IV were considered. Antioxidant activity was assessed using a 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay, whereas the biocompatibility test was performed using a brine shrimp lethality assay. The microstructure and surface morphology of the hydrogel samples containing different concentrations of Cissus quadrangularis aqueous extract was investigated using SEM. One-way ANOVA with the post hoc tukey test was performed using SPSS software v22., Results: A significant difference (P < 0.05) in the antioxidant activity was observed among the study groups. Group III reported the highest activity, whereas the control group showed the least antioxidant activity. Additionally, a significant (P < 0.01) drop in the antioxidant activity was observed in group IV when compared with group III. While assessing the biocompatibility, a significant (P < 0.001) dose-dependent increase in biocompatibility was observed with the increasing concentration of aqueous extract of Cissus quadrangularis. SEM analysis in group III showed even distribution throughout the hydrogel although the particles are close and densely arranged. Reduced antioxidant activity in group IV was probably due to clumping of the particles, thus reducing the active surface area., Conclusion: Keeping the limitations of in vitro study, it can be assumed that a carrageenan based injectable hydrogel scaffold incorporated with 20% w/v Cissus quadrangularis can provide a favourable micro-environment as it is biocompatible and possess better antioxidant property., (© 2022. The Author(s).)

Brown seaweeds usually contain alginate as a major polymer. The second major sulfated polymer in brown seaweeds is fucoidan, which has huge potential in medicinal applications. In this study, the photosynthetic pigments from Turbinaria decurrens were first extracted using chloroform/methanol in the ratio of 1:1 (v/v), followed by fucoidan extraction with yields of 5.58% (crude) and 1.28% (purified fucoidan) from the dry weight of seaweed, whereas alginate was extracted with a yield of 14.7% DW of seaweed. The isolated fucoidan possessing anticoagulation property was identified and characterized as (1-3)-α-l-fucopyranosyl residues with sulfate groups primarily at the C 4 position and to a lesser extent at the C 2 position, whereas in the case of galactose, at the C 3 and C 6 positions. The AgNPs synthesized using isolated fucoidan exhibit strong anticoagulant activity and possess a good antibacterial property against Gram-negative clinical bacteria. Functional groups such as O-H, C-H, and S=O associated with sugar residues in sulfated fucoidan are involved in the synthesis of the nanoparticles with a spherical shape, size ranging from 10 to 60 nm, and showing polydispersity. From this study, we conclude that fucoidan-coated anionic AgNPs synthesized from T. decurrens have tremendous potential in drug development., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Seaweeds rich in polysaccharides are considered commercially important because of their wide range of industrial applications. In this study, the red seaweed Kappaphycus alvarezii was used for bioplastic film production. Plasticizer polyethylene glycol (PEG) to seaweed biomass ratio was optimized and a thin bioplastic film with higher tensile strength was produced. The films obtained were characterized by its thickness, tensile strength, colour (L, a, b), elongation at break (EAB), water vapour transmission rate (WVTR) and oxygen transmission rate (OTR). TG-DSC, AFM, SEM and FTIR spectroscopy analysis were performed to assess the composition, phase transitions and chemical reaction capabilities of the film. The bioplastic film obtained from 4% K. alvarezii (whole seaweed) showed better physical and mechanical properties, whereas TG-DSC, FTIR and AFM showed similar kind of bioplastic properties in all the concentrations. Decrease in OTR was observed against decreasing wall thickness of the film. The present study suggests that the seaweed would be a potential alternate source for bioplastic production which may reduce the usage of non-degradable plastics., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Selection of indigenous and potential algal strain with high lipid content is paramount challenge in the avenues of microalgal biodiesel production. Particularly, hyper lipid producing algae with maximal triacyglycerols (TAGs) content and preferable fatty acid composition is of interest for sustainable biodiesel. Hence, the present study on comparative assessment of Chlorella vulgaris, Scenedesmus sp. and Synechococcus sp. was done in terms of cell density, lipid, TAGs and fatty acid. Higher biomass yield was obtained in Chlorella vulgaris (0.54 gL -1 ) on 13th day while maximal lipid content of 36% was observed in Scenedesmus sp. followed by Chlorella vulgaris (33%). Lipidomic analysis revealed higher non-polar lipids inChlorella vulgaris (57%) and Scenedesmus sp. (54%), whereas in Synechococcus sp. 69% polar lipids were present. In fatty acid profile, C24:0 (22.11%) was predominant in Chlorella vulgaris, while C20:0 (31.72%) and C18:2 (22.26%) was prevalent in Scenedesmus sp. and Synechococcus sp. respectively., (Copyright © 2020 Elsevier Ltd. All rights reserved.)