Extraction and Characterization of Pepsin- and Acid-Soluble Collagen from the Swim Bladders of Megalonibea fusca

Abstract

There is a growing demand for the identification of alternative sources of collagen not derived from land-dwelling animals. The present study explored the use of pepsin- and acid-based extraction protocols to isolate collagen from the swim bladders of Megalonibea fusca. After extraction, these acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) samples respectively were subjected to spectral analyses and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) characterization, revealing both to be comprised of type I collagen with a triple-helical structure. The imino acid content of these ASC and PSC samples was 195 and 199 residues per 1000 residues, respectively. Scanning electron microscopy demonstrated that samples of freeze-dried collagen exhibited a compact lamellar structure, while transmission electron microscopy and atomic force microscopy confirmed the ability of these collagens to undergo self-assembly into fibers. ASC samples exhibited a larger fiber diameter than the PSC samples. The solubility of both ASC and PSC was highest under acidic pH conditions. Neither ASC nor PSC caused any cytotoxicity when tested in vitro, which met one of the requirements for the biological evaluation of medical devices. Thus, collagen isolated from the swim bladders of Megalonibea fusca holds great promise as a potential alternative to mammalian collagen.

Effect of pH on the Structure, Functional Properties and Rheological Properties of Collagen from Greenfin Horse-Faced Filefish (Thamnaconus septentrionalis) Skin

“…G and G increased with increasing pH in the sweep frequency range of 0.01-10 Hz, indicating that pH can improve the viscoelasticity of the collagen solution. Moreover, when the pH (8,10) was greater than pI, G was higher than G in the scanning frequency range of 0.01-10 Hz. This suggests that elasticity is preferred to viscosity and that elastic behaviour is dominant in solution systems, with solutions exhibiting solid-like behaviour.…”

“…This could be because pH led to a change in internal interactions of the collagen, which changed the collagen structure. Previous literature reported that the fibrous and sheet membrane structure of collagen facilitates cell growth, wound healing and new tissue formation [8]. Therefore, it could be used in practical biomedical applications, such as wound management, biofilms and drug delivery by modifying the morphology upon adjusting the pH.…”

“…Compared with mammalian collagen, marine collagen has the advantages of high extraction yield, easier preparation and high functional properties. The extraction yields of Megalonibea fusca swim bladders collagen (33.38%) [8] and double-spotted pufferfish (Takifugu bimaculatus) skin collagen (49.83 ± 1.85%) [9] were higher than those of cattle tendon collagen (2.4-6.2%) [10], pork skin collagen (11.38% ± 0.66%) [11] and sheep slaughter by-product collagen (12.05%) and lamb slaughter by-product collagen (18.0%) [12]. The emulsifying activity index of collagen of red stingray (Dasyatis akajei) skin collagen (61.06-117.11 m 2 /g) [13] was superior to that of bactrian camel (Camelus bactrianus) hoof collagen [14] and rabbit meat collagen (44.7 m 2 /g), rabbit skin collagen (46.6 m 2 /g), rabbit ear collagen (48.2 m 2 /g) [15] and lamb slaughter by-product collagen (59.1 m 2 /g) [12].…”

“…Recently, marine collagen has been prepared and characterised by many researchers. Chen et al (2021) [4] extracted the scale collagen of the Lizardfish (Synodus macrops), Mo et al (2023) [8] isolated pepsin and acid-soluble collagen from the swim bladders of Megalonibea fusca, and Devita et al (2021) [16] isolated type I collagen from bigeye tuna (Thunnus obesus) skin via the acidenzymatic method. The greenfin horse-faced filefish (Thamnaconus septentrionalis), also known as the "skinned fish" in China, is a species of tetraodontiform fish widely distributed in the Indo-West Pacific Ocean [17,18].…”

Preparation of Enzyme-Soluble Swim Bladder Collagen from Sea Eel (Muraenesox cinereus) and Evaluation Its Wound Healing Capacity

“…Fresh sea eels were purchased from Zhoushan Farmers' Vegetable Market and pretreated before being stored at −20 The extraction of fish bladder collagen was performed following the method described by Mo et al [33]. The extraction process involved a series of sequential steps.…”