Digestive Alkaline Proteases from the Goby (Zosterisessor ophiocephalus): Characterization and Potential Application as Detergent Additive and in the Deproteinization of Shrimp Wastes

Trash to Treasure: An Up-to-Date Understanding of the Valorization of Seafood By-Products, Targeting the Major Bioactive Compounds

Fishery production is exponentially growing, and its by-products negatively impact industries' economic and environmental status. The large amount of bioactive micro- and macromolecules in fishery by-products, including lipids, proteins, peptides, amino acids, vitamins, carotenoids, enzymes, collagen, gelatin, chitin, chitosan, and fucoidan, need to be utilized through effective strategies and proper management. Due to the bioactive and healthy compounds in fishery discards, these components can be used as functional food ingredients. Fishery discards have inorganic or organic value to add to or implement in various sectors (such as the agriculture, medical, and pharmaceutical industries). However, the best use of these postharvest raw materials for human welfare remains unelucidated in the scientific community. This review article describes the most useful techniques and methods, such as obtaining proteins and peptides, fatty acids, enzymes, minerals, and carotenoids, as well as collagen, gelatin, and polysaccharides such as chitin-chitosan and fucoidan, to ensure the best use of fishery discards. Marine-derived bioactive compounds have biological activities, such as antioxidant, anticancer, antidiabetic, anti-inflammatory, and antimicrobial activities. These high-value compounds are used in various industrial sectors, such as the food and cosmetic industries, owing to their unique functional and characteristic structures. This study aimed to determine the gap between misused fishery discards and their effects on the environment and create awareness for the complete valorization of fishery discards, targeting a sustainable world.

Enzymatic approaches in the bioprocessing of shellfish wastes

Several tonnes of shellfish wastes are generated globally due to the mass consumption of shellfish meat from crustaceans like prawn, shrimp, lobster, crab, Antarctic krill, etc. These shellfish wastes are a reservoir of valuable by-products like chitin, protein, calcium carbonate, and pigments. In the present scenario, these wastes are treated chemically to recover chitin by the chitin and chitosan industries, using hazardous chemicals like HCl and NaOH. Although this process is efficient in removing proteins and minerals, the unscientific dumping of harmful effluents is hazardous to the ecosystem. Stringent environmental laws and regulations on waste disposal have encouraged researchers to look for alternate strategies to produce near-zero wastes on shellfish degradation. The role of enzymes in degrading shellfish wastes is advantageous yet has not been explored much, although it produces bioactive rich protein hydrolysates with good quality chitin. The main objective of the review is to discuss the potential of various enzymes involved in shellfish degradation and their opportunities and challenges over chemical processes in chitin recovery.

Crustacean Waste-Derived Chitosan: Antioxidant Properties and Future Perspective

Chitosan is obtained from chitin that in turn is recovered from marine crustacean wastes. The recovery methods and their varying types and the advantages of the recovery methods are briefly discussed. The bioactive properties of chitosan, which emphasize the unequivocal deliverables contained by this biopolymer, have been concisely presented. The variations of chitosan and its derivatives and their unique properties are discussed. The antioxidant properties of chitosan have been presented and the need for more work targeted towards harnessing the antioxidant property of chitosan has been emphasized. Some portions of the crustacean waste are being converted to chitosan; the possibility that all of the waste can be used for harnessing this versatile multifaceted product chitosan is projected in this review. The future of chitosan recovery from marine crustacean wastes and the need to improve in this area of research, through the inclusion of nanotechnological inputs have been listed under future perspective.

Chitin and Chitosans: Characteristics, Eco-Friendly Processes, and Applications in Cosmetic Science

Huge amounts of chitin and chitosans can be found in the biosphere as important constituents of the exoskeleton of many organisms and as waste by worldwide seafood companies. Presently, politicians, environmentalists, and industrialists encourage the use of these marine polysaccharides as a renewable source developed by alternative eco-friendly processes, especially in the production of regular cosmetics. The aim of this review is to outline the physicochemical and biological properties and the different bioextraction methods of chitin and chitosan sources, focusing on enzymatic deproteinization, bacteria fermentation, and enzymatic deacetylation methods. Thanks to their biodegradability, non-toxicity, biocompatibility, and bioactivity, the applications of these marine polymers are widely used in the contemporary manufacturing of biomedical and pharmaceutical products. In the end, advanced cosmetics based on chitin and chitosans are presented, analyzing different therapeutic aspects regarding skin, hair, nail, and oral care. The innovative formulations described can be considered excellent candidates for the prevention and treatment of several diseases associated with different body anatomical sectors.

Role of jeotgal, a Korean traditional fermented fish sauce, in microbial dynamics and metabolite profiles during kimchi fermentation

We investigated the effects of jeotgal (fermented fish sauce) on kimchi fermentation, with or without saeu-jeot and myeolchi-jeot. Bacterial community analysis showed that Leuconostoc, Weissella, Lactobacillus, and Tetragenococcus were the dominant genera; however, their succession depended on the presence of jeotgal. Leuconostoc gasicomitatum was the dominant species in kimchi without jeotgal, whereas Weissella koreensis and Lactobacillus sakei were the dominant species in kimchi with myeolchi-jeot and saeu-jeot, respectively. Metabolite analysis, using ¹H NMR, showed that the amounts of amino acids and gamma-aminobutyric acid (GABA) were higher in kimchi with jeotgal. Increases in acetate, lactate, and mannitol contents depended on fructose consumption and were more rapid in kimchi with jeotgal. Moreover, the consumption of various amino acids affected the increase in kimchi LAB. Thus, the role of jeotgal in kimchi fermentation was related to enhancement of taste, the amino acid source, and the increases in levels of functional metabolites.

Enzymes from Seafood Processing Waste and Their Applications in Seafood Processing

Commercial fishery processing results in discards up to 50% of the raw material, consisting of scales, shells, frames, backbones, viscera, head, liver, skin, belly flaps, dark muscle, roe, etc. Besides, fishing operations targeted at popular fish and shellfish species also result in landing of sizeable quantity of by-catch, which are not of commercial value because of their poor consumer appeal. Sensitivity to rapid putrefaction of fishery waste has serious adverse impact on the environment, which needs remedial measures. Secondary processing of the wastes has potential to generate a number of valuable by-products such as proteins, enzymes, carotenoids, fat, and minerals, besides addressing environmental hazards. Fishery wastes constitute good sources of enzymes such as proteases, lipases, chitinase, alkaline phosphatase, transglutaminase, hyaluronidase, acetyl glycosaminidase, among others. These enzymes can have diverse applications in the seafood industry, which encompass isolation and modification of proteins and marine oils, production of bioactive peptides, acceleration of traditional fermentation, peeling and deveining of shellfish, scaling of finfish, removal of membranes from fish roe, extraction of flavors, shelf life extension, texture modification, removal of off-odors, and for quality control either directly or as components of biosensors. Enzymes from fish and shellfish from cold habitats are particularly useful since they can function comparatively at lower temperatures thereby saving energy and protecting the food products. Potentials of these applications are briefly discussed.

Current and potential uses of bioactive molecules from marine processing waste

Food industries produce huge amounts of processing waste that are often disposed of incurring expenses and impacting upon the environment. For these and other reasons, food processing waste streams, in particular marine processing waste streams, are gaining popularity amongst pharmaceutical, cosmetic and nutraceutical industries as sources of bioactive molecules. In the last 30 years, there has been a gradual increase in processed marine products with a concomitant increase in waste streams that include viscera, heads, skins, fins, bones, trimmings and shellfish waste. In 2010, these waste streams equated to approximately 24 million tonnes of mostly unused resources. Marine processing waste streams not only represent an abundant resource, they are also enriched with structurally diverse molecules that possess a broad panel of bioactivities including anti-oxidant, anti-coagulant, anti-thrombotic, anti-cancer and immune-stimulatory activities. Retrieval and characterisation of bioactive molecules from marine processing waste also contributes valuable information to the vast field of marine natural product discovery. This review summarises the current use of bioactive molecules from marine processing waste in different products and industries. Moreover, this review summarises new research into processing waste streams and the potential for adoption by industries in the creation of new products containing marine processing waste bioactives.

Chitin extraction from shrimp shell using enzymatic treatment. Antitumor, antioxidant and antimicrobial activities of chitosan

Chitin was recovered through enzymatic deproteinization of the shrimp processing by-products. Different microbial and fish viscera proteases were tested for their deproteinization efficiency. High levels of protein removal of about 77±3% and 78±2% were recorded using Bacillus mojavensis A21 and Balistes capriscus proteases, respectively, after 3h of hydrolysis at 45°C using an enzyme/substrate ratio of 20U/mg. Therefore, these two crude proteases were used separately for chitin extraction and then chitosan preparation by N-deacetylation. Chitin and chitosan samples were then characterized by 13 Cross polarization magic angle spinning nuclear magnetic resonance (CP/MAS)-NMR spectroscopy and compared to samples prepared through chemical deproteinization. All chitins and chitosans showed identical spectra. Chitosans prepared through enzymatic deproteinization have practically the same acetylation degree but higher molecular weights compared to that obtained through chemical process. Antimicobial, antioxidant and antitumoral activitities of chitosan-M obtained by treatment with A21 proteases and chitosan-C obtained by alkaline treatment were investigated. Results showed that both chitosans inhibited the growth of most Gram-negative, Gram-positive bacteria and fungi tested. Furthermore, both chitosans exhibited antioxidant and antitumor activities which was dependent on the molecular weight.

Microbial successions and metabolite changes during fermentation of salted shrimp (saeu-jeot) with different salt concentrations

To investigate the effects of salt concentration on saeu-jeot (salted shrimp) fermentation, four sets of saeu-jeot samples with 20%, 24%, 28%, and 32% salt concentrations were prepared, and the pH, bacterial and archaeal abundances, bacterial communities, and metabolites were monitored during the entire fermentation period. Quantitative PCR showed that Bacteria were much more abundant than Archaea in all saeu-jeot samples, suggesting that bacterial populations play more important roles than archaeal populations even in highly salted samples. Community analysis indicated that Vibrio, Photobacterium, Psychrobacter, Pseudoalteromonas, and Enterovibrio were identified as the initially dominant genera, and the bacterial successions were significantly different depending on the salt concentration. During the early fermentation period, Salinivibrio predominated in the 20% salted samples, whereas Staphylococcus, Halomonas, and Salimicrobium predominated in the 24% salted samples; eventually, Halanaerobium predominated in the 20% and 24% salted samples. The initially dominant genera gradually decreased as the fermentation progressed in the 28% and 32% salted samples, and eventually Salimicrobium became predominant in the 28% salted samples. However, the initially dominant genera still remained until the end of fermentation in the 32% salted samples. Metabolite analysis showed that the amino acid profile and the initial glycerol increase were similar in all saeu-jeot samples regardless of the salt concentration. After 30–80 days of fermentation, the levels of acetate, butyrate, and methylamines in the 20% and 24% salted samples increased with the growth of Halanaerobium, even though the amino acid concentrations steadily increased until approximately 80–107 days of fermentation. This study suggests that a range of 24–28% salt concentration in saeu-jeot fermentation is appropriate for the production of safe and tasty saeu-jeot.

Chondroitin sulfate, hyaluronic acid and chitin/chitosan production using marine waste sources: characteristics, applications and eco-friendly processes: a review

In the last decade, an increasing number of glycosaminoglycans (GAGs), chitin and chitosan applications have been reported. Their commercial demands have been extended to different markets, such as cosmetics, medicine, biotechnology, food and textiles. Marine wastes from fisheries and aquaculture are susceptible sources for polymers but optimized processes for their recovery and production must be developed to satisfy such necessities. In the present work, we have reviewed different alternatives reported in the literature to produce and purify chondroitin sulfate (CS), hyaluronic acid (HA) and chitin/chitosan (CH/CHs) with the aim of proposing environmentally friendly processes by combination of various microbial, chemical, enzymatic and membranes strategies and technologies.

Zebra blenny (Salaria basilisca) viscera as a source of solvent-stable proteases: characteristics, potential application in the deproteinization of shrimp wastes and evaluation in liquid laundry commercial detergents

The present study describes the characterization of crude protease extract from zebra blenny (Salaria basilisca) and its evaluation in liquid detergent and shrimp waste deproteinization. At least five caseinolytic proteases clear bands were observed in zymogram. The crude alkaline protease showed optimum activity at pH 8.0 and 60 °C, and it was highly stable over a wide range of pH from 6.0 to 11.0. Proteolytic enzymes showed extreme stability towards non-ionic surfactants (5 % Tween 80 and 5 % Triton X-100) and oxidizing agents (1 % sodium perborate), and relative stability towards anionic surfactant (1 % Sodium dodecyl sulfate (SDS)). They also showed high stability and compatibility with various laundry liquid detergents from Tunisian market. Furthermore, the crude enzyme was stable towards several organic solvents and retained more than 50 % of its original activity after 30 days of incubation at 30 °C in the presence of 50 % (v/v) dimethylsulfoxide (DMSO). Further, proteases from zebra blenny viscera were found to be effective in the deproteinization of shrimp wastes. The protein removal after 3 h at 40 °C with an enzyme/substrate ratio (E/S) of 5 U/mg protein was about 77 %.