Shrimp Shell Research Articles

Chitosan and Metal Oxide Functionalized Chitosan as Efficient Sensors for Lead (II) Detection in Wastewater

The work presented in this paper describes the preparation and the electrochemical application of functionalized chitosan-entrapped carbon paste electrodes (CH/CPE) for lead ions (Pb2+) detection in industrial wastewater. The chitosan was first functionalized using TiO2 and CuO, which were both metal oxides that were obtained by extracting it from waste products derived from shrimp shells. The analytical performance of the as-prepared electrodes, CH/CPE, TiO2-CH/CPE, and NiO-CH/CPE, for the detection of lead (II) was examined using electrochemical impedance spectroscopy (EIS) technique in the 0.1 M KNO3 electrolyte solution. The effect of experimental conditions, including polarization potential, frequency, and pH, are optimized to maximize the sensitivity of the measurements. The developed impedimetric sensors provided a linear response over a concentration range of 10−6 to 10−4 M with a detection limit of 3.10−7 M based on S/N = 3. The DFT computational analysis demonstrated that chitosan biopolymer possesses the ability to adsorb Pb (II) ions that are present in wastewater. Chitosan and the derivatives of chitosan, have the potential to remove heavy metals from industrial effluent in a manner that is both economical and eco-friendly to the environment. Chitosan is a biopolymer that is abundantly renewable.

Development of nanocomposite chitosan films with antimicrobial activity from agave bagasse and shrimp shells

In this study, the nanocomposite chitosan films with antimicrobial activity from agave bagasse and shrimp shells were developed. Chitosan was successfully extracted from shrimp shells waste and cellulose nanofibers were obtained from bagasse agave. To improve the antimicrobial activity, different silver nanoparticle concentrations (2.5, 5, and 10% v/v) were added in the formulation. The films were prepared using the solvent casting technique and the film samples were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The functional properties were also evaluated, including transparency, antibacterial activity (against Escherichia coli), water-solubility, swelling, and mechanical properties. The moisture content and water solubility decreased when the silver nanoparticles and nanofiber were added to the films. An increase in strength and modulus was determined when the nanofibers were added to the film. and with the addition of silver nanoparticles a decrease of the mechanical properties proportional to the nanoparticle content was observed. Therefore, there was an increase in the mechanical properties of chitin films with the incorporation of nanofibers and the addition of 2.5% and 5% of silver nanoparticles. Chitosan/nanofiber-based films displayed a total antibacterial activity against E.coli compared to chitosan-based films, with a synergistic effect between chitosan and cellulose nanofibers. This work highlights the potential of chitosan films reinforced with nanofibers and silver nanoparticles to act as green alternative for food preservation and packaging.

Nitrogen-rich carbon composite fabricated from waste shrimp shells for highly efficient oxo-vanadate adsorption-coupled reduction

Protein, calcium carbonate, and chitin are abundant in shrimp shells. In this study, chemical treatment followed by hydrothermal carbonization was used to synthesize the nitrogen-rich hydrochar (HSHC) from shrimp shells. The untreated hydrochar exhibited a higher amount of calcium (25.37%) and less amount of nitrogen (2.68%) with alkaline pH (9.1). Interestingly chemical pre-treatment on shrimp shells boosted the nitrogen content to 6.81% and eliminated the calcium while controlling the pH to 6.4, which was beneficial for oxo-vanadate removal. The HSHC achieved vanadium(V) adsorption capacity of 21.20 mg/g at an optimal solution pH of 3.0, whereas the pristine hydrochar performed poorly (0.66 mg/g). The abundance of oxygen and nitrogen-based functional groups that developed through the chemical treatment resulted in improved adsorption coupled reduction performance of HSHC. This study proposed an inexpensive and environmentally friendly method for converting waste shrimp shells into value-added adsorbent.

Sustainable and selective transfer hydrogenation using waste shrimp shell‐based tetrazene‐Ru (II) para‐cymene catalyst with ethanol as a hydrogen source

Sustainable chemical research emphasizes chitosan‐based catalysts and the need to explore the direct utilization of waste shrimp shells, whereas the use of ethanol as a hydrogen source in transfer hydrogenation is less explored due to its unfavorable redox potential, higher energy barriers, generation of reactive intermediates, and catalyst poising via metal carbonyl species or decarbonylation. Herein, we disclosed an efficient synthetic approach, conducted at ambient temperature, for surface functionalization of waste shrimp shells with 3‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐1,2,4,5‐tetrazine (DMPZ‐Tz) via nucleophilic substitution using 3,6‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐1,2,4,5‐tetrazine (BDMPZ‐Tz). This method results in a color change and a 75% increase in surface nitrogen content, eliminating the need for multiple syntheses and harsh reaction conditions. We utilized the strong coordination property between DMPZ‐Tz and [Ru(p‐cym)Cl2]2/RuCl3.3H2O to develop ruthenium‐embedded transfer hydrogenation catalysts supported on shrimp shells. These catalysts were employed for the selective transfer hydrogenation of unsaturated carbonyl/aldehydes to saturated carbonyl/alcohols, utilizing ethanol as the hydrogen source and potassium carbonate as the base. The performance, selectivity, and reusability of the catalyst were thoroughly assessed through spectroscopic studies, in‐situ monitoring of the reaction progress, initial rate kinetics, and control experiments. The obtained results strongly indicated that the anchoring of DMPZ‐Tz played a crucial role in achieving superior performance compared with catalysts synthesized without it or utilizing its homogeneous counterparts. The catalyst exhibits efficient reactivity, selectivity, and broad substrate scope.

Ball milled Mg/Al hydroxides modified nitrogen-rich biochar for arsenic removal: performance and governing mechanism

Layered double hydroxides (LDHs) are widely used as effective adsorbents for wastewater treatment due to their simple synthesis, controllable structure, strong stability, large surface area, and large interfacial spacing. In this study, modified-biochar (BMBC) and Mg/Al modified-biochar composite (Mg/Al-BC) were directly prepared using ball milling technology to effectively adsorb As(V), and nitrogen-rich biochar was obtained through pyrolysis using shrimp shells as precursors. Compared to pristine biochar, the oxygen-containing functional groups of Mg/Al-BC increased by 71.9%, and the particle average diameter decreased from 14.26 nm to 12.56 nm. The kinetics and isothermal models of arsenic adsorption were examined in batch experiments to investigate the impacts of pH, temperature, and co-existing anions. The adsorption capacities for As(V) followed the order: Mg/Al-BC > BMBC > BC, with their respective maximum adsorption capacities measured at 22.65, 6.73, and 0.48 mg/g. The arsenic adsorbed onto Mg/Al-BC was dependent on pH and coexisting anions. Precipitation, ion exchange, surface complexation, and electrostatic interaction were the possible governing adsorption mechanisms. Protonation of pyridinic-N/quinone groups in biochar contributed to the electrostatic attraction between arsenic anion and quaternary ammonium cation. Stable reusability indicates that the ball milled Mg/Al-BC composite could be a promising adsorbent for arsenate removal from polluted water.Graphical

Use of Various Types of Chitosan as Edible Coating to Maintain Physical Quality of Tomatoes (Solanum lycopersicon L.) During Storage at Two Different Temperatures

Increasing tomato production requires special handling to increase longer shelf life by applying chitosan and modifying storage temperatures. Chitosan is a chitin derivative whose function is similar to wax compounds so that it is able to inhibit metabolic activity. Storage temperature of 10°C can extend shelf life and maintain the physical quality of tomatoes. This study aims to determine the effect of chitosan administration, the effect of storage temperature, and the effect of the combination of chitosan and storage temperature on the physical quality of tomatoes. This study used a Factorial Complete Randomized Design, the first factor was tomatoes without chitosan coating (K0), and tomatoes with chitosan coating (K1) = shrimp shell, (K2) = crab shell, (K3) = fish scales using the same concentration of 6%. The second factor is storage temperature (T1) = room temperature (26-32°C) and (T2) = temperature 10°C. The changes observed are shrinkage in weight, color, texture, aroma, taste based on organoleptic test (hedonic test). Data analysis using ANOVA at 5% level and BNJ follow-up test at 5% level. The results showed that the use of crab chitosan (K2) had an effect on weight loss (0.42%). Storage temperature of 10°C (T2) affects weight loss (5.04%). The best treatment combination for weight loss (0.07%) and color (7.40) was crab chitosan and temperature of 10°C (K2T2), while the best treatment combination for texture (7.56), aroma (7.08), and taste (7.16) was fish scales and temperature of 10°C (K3T2). In general, the best treatment is chitosan fish scales and a temperature of 10°C (K3T2).

Removal of lead (II) from aqueous solution using epichlorohydrin cross-linked shrimp waste-derived chitosan based @ calcium phosphates biocomposite: Experimental study and computational approach

An economical composite has been synthesized utilizing chitosan derived from discarded shrimp shells and hydroxyapatite extracted from waste bovine bones. This research delves into the composite's adsorption properties for the purpose of eliminating Pb ions from wastewater. The structure of this novel composite has been meticulously examined through techniques including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) analyses. Factors such as concentration, time, temperature, adsorbent dosage, and pH have been scrutinized to understand their impacts on lead ion adsorption. Concurrently, relevant adsorption parameters have been ascertained. Notably, the adsorption capacity, as determined by the Langmuir model, was found to be 154.88 mgg−1. To elucidate the adsorption kinetics, the PSO and IP models were employed. The adsorption enthalpy exhibited a positive value, while the free enthalpy displayed negativity. The mechanism governing adsorption was expounded upon through theoretical calculations, which concurred with and validated the experimental results.

Production, statistical evaluation and characterization of chitosanase from Fusarium oxysporum D18

PurposeThe present research work focuses on the extraction of chitosanase enzyme from soil fungi. Chitosan hydrolysis by chitosanase is one of the most effective methods to produce chitosan oligosaccharides which are new biomaterials that have many biological activities such as antitumour, antioxidant, antidiabetic and antimicrobial.MethodA strain producing chitosanase was screened and identified as Fusarium oxysporum D18 with an accession number OL343607. Various physiological parameters (incubation type, carbon source, additive nitrogen source, statistical evaluation, solid state fermentation) were assessed to increase chitosanase production.ResultsFusarium oxysporum D18 produced a considerable value of chitosanase (1.220 U/ml). After 7 days of incubation, the best carbon source was lactose, and the best nitrogen source was ammonium chloride. Statistical evaluation was carried out by using Plackett–Burman and Box-Behnken designs. The highest chitosanase production (1.994 U/ml) was induced by the medium composition g/l: KH2PO4 (1.5), MgSO4 (0.269), lactose (18), NH4Cl (1.26), pH (6.68), using a 5-day-old inoculum and chitosanase activity was 1.63 folds that of the original medium. The production of chitosanase by Fusarium oxysporum D18 in solid state cultures using different solid substrates was studied and the best solid substrate for higher chitosanase activity (2.246 U/ml) was raw shrimp heads and shells and chitosanase activity was 1.13 folds that of the optimized liquid cultures. An extracellular chitosanase was isolated and partially purified by using 75% saturation of ammonium sulphate. The highest chitosanase activity (3.667 U/ml) with a specific activity of 0.390 U/mg protein was obtained at enzyme protein concentration of 9.391 mg/ml, substrate concentration of 1.2 % (w/v), Vmax of the enzyme of approximately 0.430 U/mg protein, and KM of 0.26 % (w/v), at pH 5.6 and reaction temperature of 50 °C. The activity of the purified and characterized chitosanase increased by 3 times than that the original isolate activity. The enzyme was thermostable and retained about 55% of its original activity after heating at 70 °C for 15 min. The enzyme preparations were activated by Ca2+ ions and inactivated by Zn+2, Cu+2 ions, and EDTA.ConclusionAn antitumour activity of chitooligosaccharides produced by the chitosanase was applied to the MCF-7 (breast carcinoma cells) and they had a cytotoxicity inhibitory effect against them about IC50 = 448 μg/ml.

Sustainable preparation of hierarchical porous carbon from discarded shells of crustaceans for efficient CO2 capture

The improved CO2 adsorption capacity and selectivity is the focus of research on the carbon-based CO2 adsorbent, while nitrogen-containing groups on the surface of adsorbent have an important effect on the CO2 adsorption. In this study, nitrogen self-doped hierarchical porous carbon was prepared from three kinds of crustacean shells, namely, hairy crab shell, crayfish shell and greasyback shrimp shell. It revealed that the pore structure of porous carbon can be regulated well with the varied activation temperature and the amount of KOH. With the favorable activation temperature of 800℃ and the mass ratio of activator to carbon (A/C) of 1:1, the obtained porous carbon with different carbon precursors exhibited relatively high specific surface area (1430.63–1734.64 m2/g), large pore volume (0.70–1.48 cm3/g) and developed pore-size distribution. Consequently, among the three kinds of hierarchical porous carbon tested, that prepared form greasyback shrimp displayed the excellent CO2 adsorption of 5.144 and 4.325 mmol/g at 1 bar, 273 K and 298 K and the highest CO2/N2 selectivity was observed of 32.32, attributed to the volume of mesopore and micropore and the type of nitrogen-containing groups. The effects of nitrogen-containing groups in porous carbon on the CO2 adsorption and CO2/N2 selectivity were analyzed, and it revealed that the CO2/N2 selectivity of porous carbon was positively correlated with pyrrolic N. In conclusion, the porous structures and nitrogen-containing groups of porous carbons both contribute to the CO2 adsorption and selectivity. The porous carbon with well recycling performance in this study presented a practical application prospect.

A new route of production of the meso-porous chitosan with well-organized honeycomb surface microstructure from shrimp waste without destroying the original structure of native shells: Extraction, modification and characterization study

The highly active bio-polysaccharide based compound namely chitin and chitosan have been extracted from shrimp shell which usually expelled out extensively from food processing industries and considered as waste materials. However, by conducting demineralization, de-proteinization and deacetylation on it which could be a new route of production of valuable meso-porous chitosan that possesses a noteworthy well-organized honeycomb like surface microstructure which undoubtedly capable to form sustainable bio-composites. Whereas the honeycomb like microstructures showed a well-defined pore canals (Pc) and pore canal tubes (Pct) onto their surface. The samples were characterized via ATR-FTIR spectroscopy, High resolution SEM, AFM, EDX, XRD and 13C solid-state Cross-Polarization Magic Angle Spinning (CPMAS) NMR. The molecular weight(M‾v) of isolated chitin and chitosan were determined by viscosity and the values were 1.06 × 106(DPv = 5228), 1.8 × 104(DPv = 116) respectively besides degree of deacetylation (DDA) were measured by ATR-FTIR spectroscopy, CPMAS NMR, pH-metric titration and the values were 24&21 for chitin and 84&82 for chitosan. The results suggest that the shrimp shell waste is an attractive source of well-organized honeycomb like meso-porous chitin and chitosan with regular surface microstructures which might have a significant/potential application into the sustainable bio-composite formulation due to various industrial and biomedical sector indeed.

Two-stage process production of microbial lipid by co-fermentation of glucose and N-acetylglucosamine from food wastes with Cryptococcus curvatus

Microbial lipids were produced through a two-stage process with Cryptococcus curvatus by co-fermenting rice and shrimp shells hydrolysates. In the first stage, biomass production of glucose and N-acetylglucosamine was optimized by response surface methodology with the maximum biomass yield (17.60 g/L) under optimum conditions (43.2 g/L mixed sugar concentration, pH 5.8, 200 rpm, and 28 °C). In the second stage, according to a single-factor optimization setting (43.2 g/L sugar mixture solutions, pH 5.5, and shift time of 36 h), lipid titer of 10.08 g/L with content of 55.30 % was achieved. Scaling up to a 5-L bioreactor increased lipid content to 60.07 % with 0.233 g/g yield. When Cryptococcus curvatus was cultured in the blends of rice hydrolysates and shrimp shells hydrolysate, lipid content and yield were 52.25 % and 0.204 g/g. The fatty acid compositions of lipid were similar to those of typical vegetable oils.

Effective combination of arugula vermicompost, chitin and inhibitory bacteria for suppression of the root-knot nematode Meloidogyne javanica and explanation of their beneficial properties based on microbial analysis.

Root-knot nematodes (Meloidogyne spp.) are dangerous parasites of many crops worldwide. The threat of chemical nematicides has led to increasing interest in studying the inhibitory effects of organic amendments and bacteria on plant-parasitic nematodes, but their combination has been less studied. One laboratory and four glasshouse experiments were conducted to study the effect on M. javanica of animal manure, common vermicompost, shrimp shells, chitosan, compost and vermicompost from castor bean, chinaberry and arugula, and the combination of arugula vermicompost with some bacteria, isolated from vermicompost or earthworms. The extract of arugula compost and vermicompost, common vermicompost and composts from castor bean and chinaberry reduced nematode egg hatch by 12-32% and caused 13-40% mortality of second-stage juveniles in vitro. Soil amendments with the combination vermicompost of arugula + Pseudomonas. resinovorans + Sphingobacterium daejeonense + chitosan significantly increased the yield of infected tomato plants and reduced nematode reproduction factor by 63.1-76.6%. Comparison of chemical properties showed that arugula vermicompost had lower pH, EC, and C/N ratio than arugula compost. Metagenomics analysis showed that Bacillus, Geodermatophilus, Thermomonas, Lewinella, Pseudolabrys and Erythrobacter were the major bacterial genera in the vermicompost of arugula. Metagenomics analysis confirmed the presence of chitinolytic, detoxifying and PGPR bacteria in the vermicompost of arugula. The combination of arugula vermicompost + chitosan + P. resinovorans + S. daejeonense could be an environmentally friendly approach to control M. javanica.

Research Progress of Lytic Chitin Monooxygenase and Its Utilization in Chitin Resource Fermentation Transformation

Every year, seafood waste produced globally contains about 10 million tons of wasted crab, shrimp and lobster shells, which are rich in chitin resources. The exploitation and utilization of chitin resources are of great significance to environmental protection, economic development and sustainable development. Lytic polysaccharide monooxygenases (LPMOs) can catalyze polysaccharides by oxidative breakage of glycosidic bonds and have catalytic activity for chitin and cellulose, so they play an important role in the transformation of refractory polysaccharides into biomass. Although there have been many studies related to LPMOs, the research related to lytic chitin monooxygenases (LCMs) is still very limited. The specific catalytic mechanism of LCMs has not been fully elucidated, which poses a challenge to their application in industrial biomass conversion. This review introduces the present situation of resource development and utilization in chitin, the origin and classification of different LCMs families, the structural characteristics of LCMs and the relationship between structure and function. The research results related to activity detection, screening, preparation and transformation of LCMs were summarized and discussed. Finally, the synergistic effect of LCMs and chitin enzyme on biomass degradation was reviewed, and the existing problems and future research directions were pointed out. This is the first review focusing on Chitin-Active LPMOs in recent years, intending to provide a reference for applying chitin degradation enzymes system in the industry.

Chemical Properties of Liquid Broth Extracted from Freshwater and Marine Shrimp Shells Waste

Indonesia's shrimp industry is growing rapidly, but a surge in shrimp waste such as shells and heads shrimps are increasing as well. These waste products contain important components such as protein, minerals, and amino acids. This study aims to determine the chemical properties of liquid broth extracted from freshwater and marine shrimp shells, including ash, protein, fat, monosodium glutamate (MSG), and antioxidant. The liquid broth was extracted by boiling shrimp shells and heads in water with a ratio of 1:2 for 1 hour at 80oC. Results indicate that the type of shrimp used did not affect the broth's ash, fat, protein, MSG, or antioxidant content. Marine and freshwater shrimp liquid broths contain 0.56% and 0.28% ash, 0.10% and 0.50% fat, 2.19% and 1.97% protein, 1.5291% and 1.6274% MSG, and 2263.73 ppm and 2786.2 ppm antioxidant.

Preparation and characterization of shrimp shell waste derived carboxymethyl chitosan solid polymer electrolyte membrane

Preparation and characterization of shrimp shell waste derived carboxymethyl chitosan solid polymer electrolyte membrane

Direct sunlight induced room temperature synthesis of anticancer and catalytic silver nanoparticles by shrimp shell waste derived chitosan

The use of marine waste derived chitosan (CS) for the synthesis of nanomaterials is considered as one of the effective routes for bio-waste management and recovering functional products. Herein, CS capped silver nanoparticles (Ag NPs-CS) with potential anticancer and dye pollutants adoption properties have been synthesized photochemically under direct sunlight. To obtain, CS, shrimp shell waste was subjected to a serious of standard demineralization, deproteinization and deacetylation processes. The electronic absorption peak (400 nm) denoting surface plasmonic resonance of Ag NPs and infrared peaks relevant to CS (3364 cm−1 of OH/NH2, 2932 cm−1 of CH, and 1647 cm−1 of -CO) exhibited peaks confirmed the formation of CS-Ag NPs. Ag NPs-CS exhibited anticancer activity against Human lung adenocarcinoma cell lines (A549), the maximum cell death noticed at the concentration of 20 μg/mL and 70 μg/mL was 20 and 52 %, respectively. An aqueous Ag NPs-CS (100 μg/mL) was degraded ≥95 % of mixed dye target solution (25 mg/mL) containing equal volume of cationic dye (Methylene blue and Rhodamine B) and anionic dye (methyl orange). Therefore, these findings suggest that the shrimp shell waste derived CS can be used for the synthesis of CS-Ag NPs with potential biomedical and environmental applications.

Social Innovation through Shrimp Shell Waste Management: Concept, Implementation, and Results

Pekan Labuhan Village, Medan Labuhan District, as one of the areas that has economic potential in the form of a household-scale shrimp processing industry (Ngopek). The research question is how is the concept, implementation, and results of solving the problem of shrimp shell waste? This research was conducted in Pekan Labuhan Neighborhood Village 25 where the majority of people here produce shrimp shell waste. The research method is descriptive qualitative with a constructivist approach. Data collection techniques using interviews, observation, and documentation studies. The results of this study show that the concept applied in this program is that the management of shrimp shell waste has the potential to develop an industry for processing shrimp waste into chitin and chitosan. This program is run by a group called the Amanah Workers Group (PEMANAH). In its implementation, as a form of response to these problems, a program was created that can be said to solve these problems with the concept of integrated waste management ecosystem. Finally, the results of this program can be realized in the form of added value in at least three aspects, namely social, economic and environmental aspects.

Peningkatan Inovasi Superlizer Menggunakan Biokatalisator EM4 untuk Mempercepat Pertumbuhan Tanaman Cabai


 Based on data obtained from BPS (Central Statistics Agency) in 2012 the number of farmers is 48% of the total workforce in Indonesia of around 49.8 million people (Alexandratos and Bruinsma 2012 p: 24). This situation is not enough to make Indonesia a prosperous and developed country. This is due to the low level of productivity of agricultural products because it is not supported by the use of good and environmentally friendly fertilizers. Farmers still often use chemical fertilizers which are capable of speeding up the planting period, but on the other hand in the long run it will actually have a risky negative impact. According to BPS dataon fisheries, shrimp production in Indonesia can reach 200,000 tons per year. The shrimp shell contains protein (25% - 40%), chitin (15% - 20%), and calcium carbonate (45% - 50%). The quality of shrimp shell waste based on nutrient content and nutrients is quite good and suitablefor use as liquid fertilizer, but until now this waste has not been used optimally, causing environmental pollution, especially odors and bad environmental aesthetics. The purpose of this study was to determine the process of making liquid organic fertilizer from shrimp shell waste (SUPERLIZER) and the effect of SUPERLIZER on the growth of chili plants. The method used in this study was to use 5 sample experiments with a comparison of the composition of shrimp shells and EM4 bacteria, namely (A) 200gram:100ml, (B) 300gram:100ml, (C) 400gram:100ml, (D) 500gram:100ml, (E) ) 600gram:100ml also used chemical fertilizer and water control which was tested for 10 days. The best results were obtained for sample (E) witha ratio of 600gram:100ml which gave a 5 cm increase in length compared to chemical fertilizers which only gave a 2.8 cm increase in length.
 Keywords: shrimp shells; liquid organic fertilizer; EM4 bacteria;

Effective removal of antibiotic resistance genes from wastewater using marine waste-derived novel nanocomposites

Wastewater (WW) has been identified as a major hotspot of microbial emerging contaminants (MECs), such as antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Currently used WW treatment methods cannot efficiently eliminate these pollutants, resulting in passive contamination of adjacent environments receiving undertreated discharge. More effective WW treatment strategies are therefore urgently required. In this study, newly developed and well-characterised semi-interpenetrating polymer network (semi-IPN) hydrogels derived from the valorisation of marine wastes (e.g., shrimp shells) were investigated for their ARG removal potential. The results indicated that multiple ARGs prevalent in WW, such as ermB, qrnS, sul1 and tetO, were removed by up to 100% after being treated by novel hydrogels. In terms of horizontal gene transfer-associated genetic elements, such as integron-1 intl1, transposons tnpA1 (IS4 group) and tnpA2 (IS6 group), substantial reduction approaching 99.9% was also achieved. Moreover, up to 97% of efflux pump-associated qacEΔ1 conferring multidrug resistance (MR) was successfully attenuated. To conclude, the semi-INP hydrogels developed exhibited great potential for ARG mitigation towards strengthening WW decontamination, which provides a viable, cost-effective and environmentally friendly novel treatment approach.

Dissolution-precipitation synthesis and cold sintering of mussel shells-derived hydroxyapatite and hydroxyapatite/chitosan composites for bone tissue engineering

In the present work, seafood by-products and derivates were exploited as raw materials to produce nanocrystalline calcium phosphates-based composites in light of the rising demand for waste recovery and valorisation. Mussel shells were transformed into hydroxyapatite by dissolution-precipitation synthesis at 45 °C, whereas chitosan from shrimp shells was introduced as a reinforcing biopolymer to produce hydroxyapatite/chitosan composites. The synthesised hydroxyapatite and hydroxyapatite/chitosan composite powders were cold sintered at room temperature under 1 GPa pressure for 10 min. The materials were consolidated up to ∼90% relative density and characterized mechanically. By increasing the polymer content up to 10 wt%, the flexural strength of the sintered pellets increases from ∼45 MPa to ∼57 MPa while the hardness decreases from ∼1.1 GPa to ∼0.8 GPa, thus better addressing the mechanical properties of cortical bone. Furthermore, hydroxyapatite/chitosan composites were proven to be bioactive, this demonstrating their potential use in bone tissue engineering applications.