Recent Developments in Bio-Ink Formulations Using Marine-Derived Biomaterials for Three-Dimensional (3D) Bioprinting.

3D bioprinting is a disruptive, computer-aided, and additive manufacturing technology that allows the obtention, layer-by-layer, of 3D complex structures. This technology is believed to offer tremendous opportunities in several fields including biomedical, pharmaceutical, and food industries. Several bioprinting processes and bio-ink materials have emerged recently. However, there is still a pressing need to develop low-cost sustainable bio-ink materials with superior qualities (excellent mechanical, viscoelastic and thermal properties, biocompatibility, and biodegradability). Marine-derived biomaterials, including polysaccharides and proteins, represent a viable and renewable source for bio-ink formulations. Therefore, the focus of this review centers around the use of marine-derived biomaterials in the formulations of bio-ink. It starts with a general overview of 3D bioprinting processes followed by a description of the most commonly used marine-derived biomaterials for 3D bioprinting, with a special attention paid to chitosan, glycosaminoglycans, alginate, carrageenan, collagen, and gelatin. The challenges facing the application of marine-derived biomaterials in 3D bioprinting within the biomedical and pharmaceutical fields along with future directions are also discussed.

Sustainable Upcycling of Fisheries and Aquaculture Wastes Using Fish-Derived Cold-Adapted Proteases.

The fisheries and aquaculture industries are some of the major economic sectors in the world. However, these industries generate significant amounts of wastes that need to be properly managed to avoid serious health and environmental issues. Recent advances in marine waste valorization indicate that fish waste biomass represents an abundant source of high-value biomolecules including enzymes, functional proteins, bioactive peptides, and omega-3 rich oils. Enzyme-assisted processes, for the recovery of these value-added biomolecules, have gained interest over chemical-based processes due to their cost-effectiveness as well as their green and eco-friendly aspects. Currently, the majority of commercially available proteases that are used to recover value-added compounds from fisheries and aquaculture wastes are mesophilic and/or thermophilic that require significant energy input and can lead to unfavorable reactions (i.e., oxidation). Cold-adapted proteases extracted from cold-water fish species, on the other hand, are active at low temperatures but unstable at higher temperatures which makes them interesting from both environmental and economic points of view by upcycling fish waste as well as by offering substantial energy savings. This review provides a general overview of cold-adapted proteolytic enzymes from cold-water fish species and highlights the opportunities they offer in the valorization of fisheries and aquaculture wastes.

Production and characterization of novel hydrocarbon degrading enzymes from Alcanivorax borkumensis.

This study investigates the production of alkane hydroxylase, lipase and esterase by the marine hydrocarbon degrading bacteria Alcanivorax borkumensis. The focus of this study is the remediation of petroleum hydrocarbons, hexane, hexadecane and motor oil as model substrates. A. borkumensis showed an incremental growth on these substrates with a high cell count. Growth on motor oil showed highest alkane hydroxylase and lipase production of 2.62 U/ml and 71 U/ml, respectively, while growth on hexadecane showed the highest esterase production of 57.5 U/ml. The percentage of hexane, hexadecane, and motor oil degradation during A. borkumensis growth after 72 h, was around 80%, 81.5% and 75%, respectively. Zymogram showed two different bands with a molecular weight of approx. 52 and 40 kDa, respectively with lipase and esterase activity. Alkane hydroxylase reached optimum activity at pH 8.0 and 70 ±â€¯1 °C for hexane and hexadecane and 75 ±â€¯1 °C for motor oil. Lipase and esterase showed optimum activity at 35 ±â€¯1 °C and 40 ±â€¯1 °C, respectively and pH 7.0. The crude enzymes showed higher stability in a wide range of pH, but they were not thermostable at higher temperatures.

Low molecular weight bioactive peptides derived from the enzymatic hydrolysis of collagen after isoelectric solubilization/precipitation process of turkey by-products.

A process based on the isoelectric solubilization/precipitation (ISP) method was developed to recover collagen from low value poultry by-products. The application of the ISP process to turkey heads generated protein isolates and an insoluble biomass that was used to extract collagen. Isolated turkey head collagen was then enzymatically hydrolyzed for different time periods using alcalase, flavorzyme, and trypsin. The enzymatic hydrolysis approaches consisted of digesting collagen with each one of the 3 enzymes alone (alcalase, flavorzyme, or trypsin), or one of the 3 combinations of 2 enzymes (alcalase/flavorzyme, alcalase/trypsin, or flavorzyme/trypsin), or a cocktail of all 3 enzymes together (alcalase/flavorzyme/trypsin). The molecular weight distribution of turkey head collagen hydrolysates was determined using size exclusion chromatography and matrix-assisted laser desorption ionization-time of flight-mass spectrometry. The enzyme cocktail produced collagen hydrolysates with the greatest amount of low molecular weight peptides ranging from 555.26 to 2,093.74 Da. These collagen peptides showed excellent solubility over a wide pH range (2 -: 8) and were able to bind cholic and deoxycholic acids and significantly (P < 0.05) inhibited plasma amine oxidase in a dose- and time-dependent manner. The ISP process combined with enzyme cocktail hydrolysis represents a potential new way to produce low molecular weight bioactive collagen peptides from low value poultry by-products.

Structure elucidation of ACE-inhibitory and antithrombotic peptides isolated from mackerel skin gelatine hydrolysates.

BACKGROUND: The fish-processing industry generates significant amounts of waste and by-products that are usually discarded. This study investigated the preparation of bioactive gelatine peptides from fish skin. Gelatine was extracted from mackerel (Scomber scombrus) skin and hydrolysed by pepsin for 1, 2, 6 and 24 h. All hydrolysates were screened for antioxidant, ACE-inhibitory and antithrombotic activities. RESULTS: Gelatine peptides obtained after 24 h of hydrolysis exhibited the highest antioxidant activity (DPPH reduction ∼80%, FRAP ∼130 µmol Trolox equivalent L(-1) ). These hydrolysates had high ACE-inhibitory activity (>70%) and were able to significantly (P < 0.05) inhibit platelet aggregation by about 30%, corresponding to moderate antithrombotic activity. CONCLUSION: The bioactive properties were mainly due to the presence of low-molecular-weight peptides of 337 and 423 Da.

Evaluation of poultry protein isolate as a food ingredient: physicochemical properties and sensory characteristics of marinated chicken breasts.

The possibilities of replacing soy protein isolate (SPI) and reducing the amount of phosphate in marinated chicken breasts using poultry protein isolate (PPI) were investigated. PPI, prepared from mechanically separated turkey meat through the pH-shift technology, was used as a marinade ingredient for chicken breasts at 2 different concentrations (1.0% and 1.5%, w/w on a dry weight basis). Product characteristics were compared to samples marinated with salt, phosphate, or SPI. All the 5 treatments were subjected to instrumental and sensory analyses. Tumbling yield, drip, and cooking losses as well as expressible moisture showed that PPI can be used as a substitute for SPI in brine. The sensory analysis revealed that there were no differences among treatments in terms of appearance, color, flavor, saltiness, juiciness, tenderness, and overall acceptability of the marinated chicken breasts. However, chicken breasts marinated with phosphate had significantly higher aroma acceptability scores than those treated with 1% PPI.

Comparison between gelatines extracted from mackerel and blue whiting bones after different pre-treatments.

Gelatines were extracted from mackerel and blue whiting bones after chemical or enzymatic pre-treatments and their functional properties (solubility, foaming and emulsifying properties) were analysed. The pre-treatment significantly (p<0.05) affected the composition and the functional properties of the extracted gelatines. The amino acid analyses showed that chemically pre-treated bone gelatines had higher imino acids (proline and hydroxyproline) contents compared to those extracted after the enzymatic pre-treatment, for both fish species. It was observed that all gelatines had higher solubility at low pH with a maximum value observed at pH 2. A significant effect of ionic strength was observed. Increasing the NaCl concentration to more than 1% resulted in a significant decrease of the solubility. Mackerel bone gelatines showed lower foaming capacity (FC) and higher foaming stability (FS) than blue whiting bone gelatines. Increasing the concentration of gelatine decreased the emulsifying activity index (EAI) but increased the stability index (ESI). The use of enzymes in the pre-treatment process gave gelatines with significantly (p<0.05) higher EAI and ESI.

Stability and transformation of major flavonols in onion (Allium cepa) solid wastes.

Onion solid wastes were analysed using HPLC and LC / MS and the major polyphenols detected were quercetin, quercetin 4'-O-glucoside, accompanied by protocatechuic acid and a benzofuranone derivative. The latter two compounds have been demonstrated as some of the degradation products that might arise as a result of peroxidase-mediated decomposition of quercetin. These four substances, along with two principal enzymes implicated in flavonols breakdown, ß-glycosidase and peroxidise, were monitored throughout an examination period of 48 h, in ground onion solid waste. The determinations showed that quercetin 4'-O-glucoside content increased by 13.3%, while quercetin, benzofuranone derivative and protocatechuic acid contents increased by 68.6, 37.5 and 58.4%, respectively. ß-Glycosidase activity exhibited fluctuations and increased by 38.2%, whereas the POD showed a constant increasing trend, leading in 21.7% higher activity. On such a ground, a hypothesis was set up to explain transformations of flavonols.