Extraction and characterization of chitin, chitosan, and protein hydrolysate from the invasive Pacific blue crab, Portunus segnis (Forskål, 1775) having potential biological activities

Maximizing crustaceans (shrimp, crab, and lobster) by-products value for optimum valorization practices: A comparative review of their active ingredients, extraction, bioprocesses and applications

BACKGROUND

The processing of the three major crustaceans (shrimp, lobster, and crab) is associated with inevitable by-products, high waste disposal costs, environmental and human health issues, loss of multiple biomaterials (chitin, protein hydrolysates, lipids, astaxanthin and minerals). Nowadays, these bioresources are underutilized owing to the lack of effective and standardized technologies to convert these materials into valued industrial forms.

AIM OF REVIEW

This review aims to provide a holistic overview of the various bioactive ingredients and applications within major crustaceans by-products. This review aims to compare various extraction methods in crustaceans by-products, which will aid identify a more workable platform to minimize waste disposal and maximize its value for best valorization practices.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The fully integrated applications (agriculture, food, cosmetics, pharmaceuticals, paper industries, etc.) of multiple biomaterials from crustaceans by-products are presented. The pros and cons of the various extraction methods, including chemical (acid and alkali), bioprocesses (enzymatic or fermentation), physical (microwave, ultrasound, hot water and carbonic acid process), solvent (ionic liquids, deep eutectic solvents, EDTA) and electrochemistry are detailed. The rapid development of corresponding biotechnological attempts present a simple, fast, effective, clean, and controllable bioprocess for the comprehensive utilization of crustacean waste that has yet to be applied at an industrial level. One feasible way for best valorization practices is to combine innovative extraction techniques with industrially applicable technologies to efficiently recover these valuable components.

Current and Expected Trends for the Marine Chitin/Chitosan and Collagen Value Chains

Chitin/chitosan and collagen are two of the most important bioactive compounds, with applications in the pharmaceutical, veterinary, nutraceutical, cosmetic, biomaterials, and other industries. When extracted from non-edible parts of fish and shellfish, by-catches, and invasive species, their use contributes to a more sustainable and circular economy. The present article reviews the scientific knowledge and publication trends along the marine chitin/chitosan and collagen value chains and assesses how researchers, industry players, and end-users can bridge the gap between scientific understanding and industrial applications. Overall, research on chitin/chitosan remains focused on the compound itself rather than its market applications. Still, chitin/chitosan use is expected to increase in food and biomedical applications, while that of collagen is expected to increase in biomedical, cosmetic, pharmaceutical, and nutritional applications. Sustainable practices, such as the reuse of waste materials, contribute to strengthen both value chains; the identified weaknesses include the lack of studies considering market trends, social sustainability, and profitability, as well as insufficient examination of intellectual property rights. Government regulations, market demand, consumer preferences, technological advancements, environmental challenges, and legal frameworks play significant roles in shaping both value chains. Addressing these factors is crucial for seizing opportunities, fostering sustainability, complying with regulations, and maintaining competitiveness in these constantly evolving value chains.

Chitin/chitosan extraction from shrimp shell waste by a completely biotechnological process

Two lactic bacteria were used in sequential co-cultures to demineralize (DM) and deproteinize (DP) shrimp shells (SS) to obtain chitin. During the first 24 h, Lactobacillus delbrueckii performed the DM in a minimal medium containing 100 g/L SS and 50 g/L glucose. Then, three different conditions were assayed to complete DM and perform the DP stage: 1) Bifidobacterium lactis was added with 35 g/L of glucose (Ld-G → Bl-G); 2) only B. lactis was added (Ld-G → Bl); and 3) a 35 g/L pulse of glucose was added, and at 48 h, B. lactis was inoculated (Ld-G → G → Bl). The highest DM (98.63 %) and DP (88 %) were obtained using a glucose pulse in the DM step and controlling the pH value above 6.0 in the DP step. Finally, a deacetylases cocktail produced by Aspergillus niger catalyzed the deacetylation of the resulting chitin. The chitosan samples had a deacetylation degree higher than 78 % and a solubility of 25 % in 1.0 N acetic acid. The deacetylation yield was 74 % after a mild chemical treatment, with a molecular weight of 71.31 KDa. This work reports an entirely biological process to get chitin and chitosan from SS with high yields.

Nile crab Potamonautes niloticus shell extract: Chromatographic and molecular elucidation of potent antioxidant and anti-inflammatory capabilities

Diseases emerging from oxidative stress and inflammatory imbalance are deeply threatening the modern world. Fisheries by-products are rich in bioactive metabolites. However, they are usually discarded, posing a real environmental burden. Herein we aimed to explore the bioactive compounds, anti-oxidant, and anti-inflammatory capabilities of the shell of the freshwater Nile crab Potamonautes niloticus. Methanolic extract of crab shell was subjected to GC/MS and HPLC analyses of total lipids, flavonoids, and phenolic acids. Also, zebrafish Danio rerio was subjected to inflammatory status using CuSO₄, then treated with different doses of shell extract. Total antioxidant capacity and QPCR analyses for gene expression of different antioxidant enzymes, i.e. superoxide dismutase(sod), catalase (cat), and glutathione peroxidase (gpx) and pro-inflammatory cytokines, i.e. tumor necrosis factor alpha (tnf-α), nuclear factor kappa B (nf-κb), interleukin 1-Beta (il-1b) were assessed. The results showed the richness of crab shell extract with ω - 9 (32.78 %), ω - 7 (6.37 %), and ω - 6 (4 %) unsaturated fatty acids. Diverse phenolic acids and flavonoids were found, dominaed by Benzoic acid (11.24 µg mL^-1), Syringic acid (11.4 µg mL^-1), Ferulic acid (10.55 µg mL^-1), Kampferol (9.47 µg mL^-1), Quercetin (6.33 µg mL^-1), and Naringin (4.16 µg mL^-1). Crab extract also increased the total antioxidant capacity and oxidative stress enzymeś mRNA levels by 1.3-2.15 folds. It down-regulated pro-inflammatory cytokineś mRNA levels by 1.3-2 folds in comparison to positive control (CuSO₄-induced) zebrafishes. The net results indicated that Nile crab shell extract is a rich source of anti-oxidant and anti-inflammatory compounds. Therefore, we recommend to continuously explore the bioactive capabilities of exoskeletons of different shellfish species. This can provide additive values for these products and reduce the environmental burden of their irresponsible discarding.