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Natural deep eutectic solvents (NaDES) were used to extract bioactive compounds from marine by-products: codfish bones, mussel meat, and tuna vitreous humor. NaDES were prepared using natural compounds, including lactic acid (Lac), fructose (Fru), and urea (Ur), and were characterized to define their physicochemical properties, including the viscosity, density, surface tension, and refractive index. FTIR and NMR analysis confirmed the presence of intermolecular hydrogen bonding in NaDES. The extracts obtained using these NaDES were characterized to define their composition. Results demonstrated that the extract’s composition differed highly, depending not only on the DES used, but also on the structure and composition of the raw material. Proteins and lipids were mainly present in extracts obtained from mussels, while ash content was highest in the extracts obtained from codfish bones. The biocompatibility of NaDES and the soluble fractions (SF) of the raw materials in NaDES was evaluated, and it was possible to conclude that the soluble ingredients obtained from the raw materials improved the biocompatibility of NaDES.

Based on a biotechnological strategy, in the present work several peptones are produced from the Alcalase hydrolysis (0.1–0.2% v/w, 56–64 °C, pH 8.27–8.98, 3 h) and thermal processing (105 °C, 60 min) of wastes generated from the industrial processing of turbot, salmon, trout, seabream and seabass. These peptones were included (in the range of 2.6–11 g/L of soluble protein) as main source of organic nitrogen (protein substrates) in low-cost media for the culture of lactic acid bacteria (LAB), marine probiotic bacteria (MPB) and ubiquitous Gram+ bacteria. In most cases, batch fermentations conducted in aquaculture peptone media led to the best growth, metabolic productions and yields. Nevertheless, no significant differences between aquaculture peptones and commercial media were generally observed. Kinetic parameters from a logistic equation and used for cultures modeling were applied with the purpose of comparing the bioproduction outcomes. In economical terms, the validity of the aquaculture peptones as substitutives of the peptones (meat extract, casitone, etc.) from commercial media was also compared. The decreasing of the costs for LAB bioproductions ranged between 3–4 times and the growth costs of MPB and Gram+ bacteria were improved more than 70 and 15 times, respectively, in relation to those found in control commercial media.

Following the growth of the global population and the subsequent rapid increase in urbanization and industrialization, the fisheries and aquaculture production has seen a massive increase driven mainly by the development of fishing technologies. Accordingly, a remarkable increase in the amount of fish waste has been produced around the world; it has been estimated that about two-thirds of the total amount of fish is discarded as waste, creating huge economic and environmental concerns. For this reason, the disposal and recycling of these wastes has become a key issue to be resolved. With the growing attention of the circular economy, the exploitation of underused or discarded marine material can represent a sustainable strategy for the realization of a circular bioeconomy, with the production of materials with high added value. In this study, we underline the enormous role that fish waste can have in the socio-economic sector. This review presents the different compounds with high commercial value obtained by fish byproducts, including collagen, enzymes, and bioactive peptides, and lists their possible applications in different fields.

NRC publication: Yes

The seafood industry generates large volumes of waste. These include processing discards consisting of shell, head, bones intestine, fin, skin, voluminous amounts of wastewater discharged as effluents, and low-value under-utilized fish, which are caught as by-catch of commercial fishing operations. The discards, effluents, and by-catch are rich in nutrients including proteins, amino acids, lipids containing good proportions of polyunsaturated fatty acids (PUFA), carotenoids, and minerals. The seafood waste is, therefore, responsible for loss of nutrients and serious environmental hazards. It is important that the waste is subjected to secondary processing and valorization to address the problems. Although chemical processes are available for waste treatment, most of these processes have inherent weaknesses. Biological treatments, however, are environmentally friendly, safe, and cost-effective. Biological treatments are based on bioconversion processes, which help with the recovery of valuable ingredients from by-catch, processing discards, and effluents, without losing their inherent bioactivities. Major bioconversion processes make use of microbial fermentations or actions of exogenously added enzymes on the waste components. Recent developments in algal biotechnology offer novel processes for biotransformation of nutrients as single cell proteins, which can be used as feedstock for the recovery of valuable ingredients and also biofuel. Bioconversion options in conjunction with a bio-refinery approach have potential for eco-friendly and economical management of seafood waste that can support sustainable seafood production.

Since the establishment of the coastal industrial complex in Gabes city (Gulf of Gabes, SE Tunisia), hundred million tons of untreated phosphogypsum have been discharged in the open sea causing serious environmental problems. To better understand the dynamic and behavior of phosphate/phosphogypsum contaminants from raw ores to marine environment, a chemical, organic, mineralogical, and morphological characterization of phosphate rock and phosphogypsum was conducted using several sophisticated techniques. The chemical analysis showed that phosphate and phosphogypsum contain high loads of trace elements and that the transfer factors of pollutants varied from 5.83% (U) to 140% (Hg). Estimated annual flows of phosphogypsum contaminants into the marine environment ranged between 0.05 (Re) and 87,249.60 (F) tons. The phosphate rock was found to be formed by carbonate fluorapatite, calcite, dolomite, natural gypsum, quartz, calcite-Mg, apatite, pyrite, fluorite, and sphalerite-Cd and phosphogypsum by synthetic gypsum and sphalerite-Cd. The phosphate was found to be richer in organic compounds compared to phosphogypsum. Based on this work, the Tunisian phosphogypsum has a high mining potential and encourages the development of an economically beneficial and environmentally friendly phosphogypsum-treating industry.

Sargassum spp. are brown algae present in the tropical and subtropical waters of the world’s oceans. Benthic or pelagic, Sargassum spp. represent substantial amounts of biomass when drifted and massive beaching events also named “golden tides” are challenging for environmental and tourism managers. The Sargassum spp. biomass can be regarded as offering economic opportunities; however, micropollutant contamination counteracts this wealth. This review describes the contaminant uptake processes and the concentrations reached by various Sargassum species in regard to national and international norms for a variety of applications. Amongst the heavy metals, perhaps total arsenic content is the most salient: phytoaccumulation of arsenic is due to confusion in the phosphate transporter between arsenic and phosphate, thus leading Sargassum spp. to bioaccumulate arsenic actively. The levels reached could well give cause for concern across all potential applications, in particular for human and animal use. Similarly, there are concerns for the widespread applications or disposal of this biomass due to environmental impacts in the case of storage, landfill or composting. Organic micropollutants are too rarely studied to assert that there is global contamination. However, research studies focused on Sargassum spp. contamination confirmed environmental threats. But, without exhaustive analysis of routine algae contamination, the standard contamination level cannot be defined. Treating beach-cast or drifting Sargassum spp. as a waste is a Gordian knot, in that it involves investment, work and disposal surfaces, whilst not necessarily providing environmental and economic gains. However, Sargassum spp. are a raw material, a resource rich in a broad variety of constituents that could be processed for commercial applications or which could be used for production of energy. In this paper the authors review the diverse applications that can be considered and describe the relevant regulations and norms related to contaminants and effluents that need to be taken into account. However, if valorizing Sargassum spp. is currently valuable and promising, the quality of the raw material is a key starting point because fresh and sand-free algae are required: offshore gathering solutions need to be developed in order to limit Sargassum sp. contamination by pollutants from land so as to hinder algae decay.

This review summarizes recent data related to the management of marine plastic litter to promote sustainable development. It discusses the distribution and identification of marine plastic litter, assesses the potential socio-economic and environmental impacts of these pollutants, and explores their recovery strategies, from a circular economy perspective. The main findings indicate that the majority of marine plastic litter originates from land-based sources. Current technologies and approaches for valorizing marine plastic litter include mechanical and chemical recycling, blockchain technologies by providing traceability, verification, efficiency and transparency throughout the recycling process, and public awareness programs and education. The developed policies to prevent marine plastic litter emphasize regulations and initiatives focused toward reducing plastic use and improving plastic waste management. By adopting a holistic and sustainable approach, it is possible to mitigate the environmental impact of marine plastic debris while simultaneously creating economic opportunities.

This study assessed the effects of substituting fish meal and soybean meal with an algal meal and Brewers’ spent grains (BSG), respectively, on the overall health of the carp, Cirrhinus reba . 18S rDNA sequencing identified the targeted alga as  Chlorella sorokiniana  SCB (Genbank accession no. OQ702656.1) and the alga was cheaply cultivated in raw poultry litter leachate to prepare the  Chlorella  meal. A control diet (FS) containing 30% protein was formulated with fish meal and soybean meal. Three experimental diets were formulated to contain  Chlorella  meal and soybean meal (CS), fish meal and BSG (FB), and  Chlorella  meal and BSG (CB) as protein ingredients. Developmental parameters were significantly enhanced in carp fed diets composed of  Chlorella  meal and BSG. The content of serum protein was the highest in fish fed the CS diet, while the highest liver functioning was in the CB group. An enhancement of carcass protein and a slight decrease in carcass lipid was observed in fish fed with algal and BSG-incorporated diets. The levels of saturated fatty acids and mono-unsaturated fatty acids were greatly reduced, while the long-chain polyunsaturated fatty acid contents were significantly enhanced in the carcasses of carp fed the CB diet. The apparent digestibility of the feeds and feed ingredients were evaluated, and  Chlorella  and BSG meals had a good digestibility profile. The estimated price of CB feed was 53.72% lower than the corresponding conventional diet. The experiments showed that  Chlorella  meal and BSG can successfully substitute the conventional protein ingredients in the feed for  C. reba  without producing any negative impact on growth and nutrient utilization. This is the first report for the assessment and establishment of a combination of an alga and BSG meals as protein sources in fish feed.

This study investigated the optimal combination of compatibilizers and stabilizers to enhance the value of marine environment plastic (MEP). The composition of the plastics was analysed, and a simulated recycled plastic blend (sMEP) was prepared based on a simplified composition of actual MEP. Different concentrations of three commercial compatibilizers (C1, C2 and C3) were tested to improve tensile strength. The tensile tests indicated that the blend compatibilized with 10 wt.% C3 (polypropylene grafted with maleic anhydride) exhibited the highest increase in tensile strength. This optimal compatibilization was then combined with two commercial stabilizers and applied to a simulated MEP blend. Scanning electron microscopy images showed that all blends had a continuous polyethylene phase with dispersed poly(ethylene terephthalate) (PET) and polypropylene (PP) droplets. The simulated blend with 10 wt.% C3 exhibited a reduced PET droplet size in the dispersed phase. Differential scanning calorimetry results revealed a decrease in polyethylene crystallinity and an increase in PP crystallinity. The improved properties of the blend were attributed to the effectiveness of the C3 compatibilizer in enhancing the interface between the PP and PET phases. An effective formulation was developed to valorise marine-sourced plastics by leveraging existing scientific knowledge and accessible commercial additives. Applying this enhanced formulation to real MEP not only demonstrated its effectiveness, but also highlighted a practical approach for reducing plastic pollution and supporting circular economy principles, contributing to environmental conservation efforts.