Seaweeds for the sustainable blue economy development: A study from the south east coast of Bangladesh

Conceptual design and environmental evaluation of the Biorefinery approach for R-phycoerythrin extraction and purification

Marine algae are considered promising resources both at present and in the near future. Their availability, together with their molecular structure and properties, increases their applicability in various sectors: food and feed, cosmetics, pharmaceuticals and bioenergy. However, the "bio" qualification does not always imply a lower impact compared to fossil-based process schemes. Therefore, to verify the suitability of algae-based scenarios from a sustainable and circular perspective, it is necessary to assess their sustainability potential through process modelling (scaling up from laboratory scale to evaluate their potential at commercial level), environmental assessment (using the Life Cycle Assessment (LCA) method) and circularity analysis (by quantifying circularity indicators focusing on recovery, waste management and effective use of resources). In this context, this research report focused on the techno-economic assessment (TEA) and LCA of three alternative scenarios based on the extraction of R-phycoerythrin from offshore harvested macroalgae: water extraction followed by enzymatic digestion (S01), ultrasound-assisted extraction (S02) and water extraction (S03). In addition, the evaluation of environmental, social and circularity indicators and the application of the Greenness Grid methodology were included. According to the results obtained, S01 is the most promising alternative among the three scenarios due to its process productivity, lower environmental impact and potential sustainable scenario score according to the Green Chemistry assessment. Regarding the economic perspective, S03 is the only one that does not reach economic viability. Future studies should focus on improving process efficiency, promoting the use of renewable energy resources and supporting technological progress in emerging extraction processes.

Biomedical properties, characterization of seaweeds species and antimicrobial activity

Marine organisms produce a variety of compounds with pharmacological activities. In order to better comprehend the medicinal value of five particular seaweed orders Ulvales (Ulva intestinalis), Bryopsidales (Codium decorticatum), Ectocarpales (Iyengaria stellata), Dictyotales (Spatoglossum aspermum) and Gigartinales (Hypnea musciformis), a bioactive analysis including the screening of phytochemical components, antioxidant and antimicrobial activities was the aim of the investigation. The species include U. intestinalis was collected from Sandspit, while C. decorticatum, I. stellata, S. aspermum, and H. musciformis were gathered from Buleji. These species evaluated for their ability to inhibit human infectious gram positive pathogens Staphylococcus aureus, Staphylococcus epidermidis as well as gram negative bacteria Escherichia coli. Additionally vegetable pathogen Fusarium oxysporum, and fruit pathogens (Aspergillus niger and Aspergillus flavus) were evaluated to determine the zone of inhibition. Two organic solvents, ethanol and methanol, were used to prepare seaweed extract. The disc diffusion method was utilized to quantify the zone of inhibition and the DPPH method was employed to measure the antioxidant activity. The study unveiled various phyto-constituents in the tested seaweeds, with flavonoids, tannins, and proteins found in all selected species, while saponins, terpenoids, and carbohydrates were absent in I. stellata and S. aspermum. Notably, ethanolic extracts of I. stellata and S. aspermum demonstrated superior higher antioxidant activity, with increasing percentages of inhibition from 1 to 6 mg/ml. Furthermore, the findings indicated that the ethanolic extract of U. intestinalis displayed the highest resistance against F. oxysporum and A. flavous among other seaweeds. Meanwhile, the ethanolic extract of C. decorticatum exhibited the highest resistance against A. Niger. Additionally, the ethanolic extract of I. stellata and H. musciformis displayed the highest resistance against the gram-negative bacteria E. coli and the gram-positive bacteria S. epidermidis, whereas the methanolic extract of U. intestinalis demonstrated the highest resistance against the gram-positive bacteria S. aureus. The findings of this investigation show that a range of bioactive compounds with antioxidant properties are involved in the antimicrobial activities of disease-causing pathogens.

Leveraging marine biotechnology for an All-Atlantic sustainable blue economy

Despite the lack of research, development, and innovation funds, especially in South Atlantic countries, the Atlantic is suited to supporting a sustainable marine bioeconomy. Novel low-carbon mariculture systems can provide food security, new drugs, and climate mitigation. We suggest how to develop this sustainable marine bioeconomy across the entire Atlantic.

Seaweed Growth Monitoring with a Low-Cost Vision-Based System

In this paper, we introduce a method for automated seaweed growth monitoring by combining a low-cost RGB and stereo vision camera. While current vision-based seaweed growth monitoring techniques focus on laboratory measurements or above-ground seaweed, we investigate the feasibility of the underwater imaging of a vertical seaweed farm. We use deep learning-based image segmentation (DeeplabV3+) to determine the size of the seaweed in pixels from recorded RGB images. We convert this pixel size to meters squared by using the distance information from the stereo camera. We demonstrate the performance of our monitoring system using measurements in a seaweed farm in the River Scheldt estuary (in The Netherlands). Notwithstanding the poor visibility of the seaweed in the images, we are able to segment the seaweed with an intersection of the union (IoU) of 0.9, and we reach a repeatability of 6% and a precision of the seaweed size of 18%.

Effects of Fermented Seaweed Fertilizer Treatment on Paddy Amino Acid Content and Rhizosphere Microbiome Community

Seaweed has often been reported on for it potential bioresources for fertilizers to improve crop productivity and reduce the use of chemical fertilizers (CF). However, little is known about the nutritional status of the crop grown with the implementation of seaweed fertilizers (SF). In this study, the amino acid content of rice produced by SF implementation was evaluated. Furthermore, the rhizosphere bacterial community was also investigated. The paddy seedlings were divided into five groups, control (C0), chemical fertilizer (CF), seaweed fertilizer (SF), chemical and seaweed fertilizer combination 25:75 (CFSF1), and chemical and fertilizer combination 50:50 (CFSF2). The CFSF2 group shown significantly better growth characteristics compared to other groups. Based on the concentration of macronutrients (N, P, K) in paddy leaf, CFSF2 also shown the best results. This also correlates with the abundant amino acid composition in CFSF2 in almost all tested amino acids, namely, serine, phenylalanine, isoleucine, valine, glycine, tyrosine, proline, threonine, histidine, and arginine. Interestingly, beneficial bacteria Rhizobiales were significantly higher in CFSF2-treated soil (58%) compared to CF (29%). Another important group, Vicinamibacterales, was also significantly higher in CFSF2 (58%) compared to CF (7%). Hence, these potentially contributed to the high rice amino acid content and yield in the CFSF2-treated paddy. However, further field-scale studies are needed to confirm the bioindustrial application of seaweed in agricultural systems.