Shrimp Shell Research Articles

الخصائص الفيزيوكيميائية للكيتوزان المستخلص من قشور الجمبري المصطادة على طول الساحل الليبي

This study aims to assess the possibility of extracting chitosan extracted from shrimp collected from the Libyan coast, to study some of its physiochemical properties, and to classify it compared to those extracted from imported shrimp available in the Libyan market in Tripoli. The physical and chemical properties of chitosan were studied including fat-binding capacity (FBC), water-binding capacity (WBC), throughput, solubility, moisture content, ash, protein, lipid, and degree of deacetylation of chitosan. The results showed that the moisture content was 28.025% in the untreated shrimp shells. The chitin sample contained 10.166% of moisture, compared to 2.677% only in the chitosan sample. Fresh local shrimp shells contained 4.70% ash, whereas the ash content in the imported sample was 53.62%. The extracted chitin and chitosan samples recorded 0.45% and 2.05% ash content, respectively. Local shrimp shells contained 28% of protein. 4.16% protein content was found in chitin extract from locally collected shrimp shells, against 0.098% in extracts from imported shrimp shells. Moreover, local shrimp shell samples contained 0.668% of fat, against 5.86% fat content in imported samples. Chitin and chitosan extracted from local shrimp shells contained 0.74% and 2.50% fat, respectively. Chitosan extracted from imported shrimp shells had a fat content of 7.307%. Fresh shrimp yielded 14.04% of chitosan, with a 0.329% the chitosan extracts from the local shrimp shells, compared to 8.5% extracts from the imported shrimp shells. A deacetylation score of 9.944 was found in chitosan extracted from both local and imported chimpanzees. The solubility of chitosan extracted from domestic shrimp shells was 0.329%, against an 8.5% solubility of chitosan extracted from imported shells. The solubility of locally extracted chitosan is, therefore, comparatively weaker. The water-binding capacity (WBC) of chitosan extracted from local and imported shrimp shells were found to be 485.6% and 483.2%, respectively. The ability of chitosan extracted from local shrimp shells showed a fat binding capacity (FBC) of 611% against a capacity of 764% of imported chitosan. Although this study succeeded in extracting chitin and chitosan from local and imported shrimp shells using chemical treatment, chitosan production was significantly poor, compared to previous studies. Keywords: Fat binding capacity, Fresh shrimp, Physiochemical properties, Solubility of chitosan

Impact of chitosan-raw-material (Shrimp shell powder) on the grain yield and agronomic characteristics of transplanted aman rice (BRRI dhan56)

Impact of chitosan-raw-material (Shrimp shell powder) on the grain yield and agronomic characteristics of transplanted aman rice (BRRI dhan56)

Antifungal efficacy of chitosan extracted from shrimp shell on strawberry (Fragaria × ananassa) postharvest spoilage fungi

The strong demand for biological materials in the food industry places chitosan at the forefront of other biopolymers. The present study aims to evaluate the antifungal properties of chitosan extracted from shrimp shell waste (Parapenaeus longirostris) against post-harvest strawberry (Fragaria × ananassa) spoilage fungi. The physicochemical characteristics (DD, Mw, and solubility) of extracted chitosan were determined. In addition, functional characteristics were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antifungal effect of chitosan on mycelial growth and spore germination of Aspergillus niger, Botrytis cinerea, Fusarium oxysporum, and Rhizopus stolonifer was evaluated. Yield, degree of deacetylation, molecular weight, and solubility were 21.86%, 83.50%, 180 kDa, and 80.10%, respectively. A degree of deacetylation of 81.27% was calculated from the FTIR spectrum and a crystallinity index of 79.83% was determined from the X-ray diffraction pattern. SEM images of extracted chitosan showed a combination of fibrous and porous structure. At 3% chitosan, mycelial growth inhibition rates of A. niger, B. cinerea, F. oxysporum, and R. stolonifer ranged from 81.37% to 92.70%. At the same chitosan concentration, the percentages of spore germination inhibition of the isolated fungi ranged from 65.47% to 71.48%. The antifungal activity was highly dose-dependent. As a natural polymer, chitosan offers a convincing alternative to synthetic antimicrobials for the post-harvest preservation of strawberries. Its potential lies in its ability to inhibit the growth of spoilage fungi.

SURVEY ON BIOMATERIAL SHRILK AS SUTURES IN MEDICAL FIELD

Shrilk stands as an innovative biomaterial, fusing the robustness of chitosan, a synthetic plastic, with the resilience of shrimp shells. The term "shrilk" itself is a blend of "shrimp" and "silk," emblematic of the distinctive attributes inherent in this material. Chitosan, derived from chitin present in the exoskeletons of crustaceans like shrimps and crabs, boasts biocompatibility, biodegradability, and antimicrobial qualities. Biopolymers have garnered increased attention owing to their remarkable attributes such as biocompatibility, biodegradability, non-toxicity, and functionality. These characteristics position biopolymers as promising candidates for a wide range of surgical applications, including but not limited to bioadhesives, sealants, sutures, and wound dressings. Dubbed "shrilk" by its creators, Postdoctoral fellow Javier Fernandez and Wyss Institute director Donald Ingber, this substance mimics insect cuticle, a material found in insect exoskeletons. Shrilk serves as the synthetic equivalent to one of nature's most robust, lightweight, and intriguing materials. This article underscores the potential use of shrilk in surgical applications, particularly as sutures, considering its properties in comparison to currently employed sutures.

Filamen printer 3D berbasis limbah PET (polyethylene terephthalate) dan kitosan cangkang udang

One alternative for processing PET (polyethylene terephthalate) plastic waste is to convert it into a basic material for making 3D printer filaments with the addition of shrimp shell chitosan. The addition of shrimp shell chitosan to the filament can increase its mechanical strength. The aim of this research is to determine the best formulation and effectiveness of the combination of PET plastic with chitosan as 3D printer filament on the mechanical properties and microstructure of the surface. Making 3D printer filament from a combination of PET and shrimp shell chitosan using a double screw extruder with varying ratios between PET and shrimp shell chitosan (99 : 1, 97.5 : 2.5 and 95 : 5) with temperature variations at 175° C (Hopper Zone ), 195°C, 225°C, 245°C (Die zone) using a screw rotation speed of 50 rpm, with the testing process including a tensile test, to determine the mechanical properties of the material by analysis using the SEM (Scanning Electron Microscope) test ) to identify the surface morphology and size of the filament material. The test results for composition 99:1 (sample 1) had the lowest tensile strength value of 35.79 MPa, breaking 0.10 mm with an elongation value of 0.32%. Composition 97.5:2.5 (sample 2) with a tensile strength value of 96.20 Mpa, longest breaking length of 0.13 mm and highest elongation value of 0.42%. Composition 95:5 (sample 3) only has the highest tensile value of 98.95 MPa, with a breaking length of 0.06 mm and the lowest elongation of 0.18%.

Shrimp Waste Upcycling: Unveiling the Potential of Polysaccharides, Proteins, Carotenoids, and Fatty Acids with Emphasis on Extraction Techniques and Bioactive Properties.

Shrimp processing generates substantial waste, which is rich in valuable components such as polysaccharides, proteins, carotenoids, and fatty acids. This review provides a comprehensive overview of the valorization of shrimp waste, mainly shrimp shells, focusing on extraction methods, bioactivities, and potential applications of these bioactive compounds. Various extraction techniques, including chemical extraction, microbial fermentation, enzyme-assisted extraction, microwave-assisted extraction, ultrasound-assisted extraction, and pressurized techniques are discussed, highlighting their efficacy in isolating polysaccharides, proteins, carotenoids, and fatty acids from shrimp waste. Additionally, the bioactivities associated with these compounds, such as antioxidant, antimicrobial, anti-inflammatory, and antitumor properties, among others, are elucidated, underscoring their potential in pharmaceutical, nutraceutical, and cosmeceutical applications. Furthermore, the review explores current and potential utilization avenues for these bioactive compounds, emphasizing the importance of sustainable resource management and circular economy principles in maximizing the value of shrimp waste. Overall, this review paper aims to provide insights into the multifaceted aspects of shrimp waste valorization, offering valuable information for researchers, industries, and policymakers interested in sustainable resource utilization and waste-management strategies.

A universal synthesis strategy for facile and scalable of magnetic biochar composite materials for PMS activation: Catalytic mechanisms

Biochar-based catalysts have shown great promise for application in AOPs due to their wide source and good performance, while its development is limited by its complicated preparation process and large variation in performance. Herein, a series of magnetic biochar composites(Fe@NC-XX) based on different biomass (duckweed, shrimp shell, peanut shell, corncob, and pomelo peel) were fabricated via one-pot pyrolysis method. The removal of sulfadiazine (SDZ) by all materials reached more than 90% within 20 min. The characterization results indicated that the special structure of Fe encapsulated in nitrogen-doped carbon nanotubes (CNTs) was the main reason why this approach is not limited to specific biomass. Acts as a catalytic center, Fe catalyzes the formation of CNTs during annealing. Meanwhile, graphene sheets and carbon nanoparticles formed by melamine and biomass decomposition migrate to the nucleus surface to form a hollow structure of CNTs. In addition, the results of quenching experiments and ESR tests elucidated that surface-bound radicals accumulated on the surface of CNTs, which can remarkably boost the efficient removal of SDZ. Consequently, the synthetic strategy of Fe nanoparticles anchored in N-doped CNTs that are not selective for biomass provides a new pathway for a universal synthesis method of biochar-based catalysts.

Metabolic and Bioprocess Engineering of Clostridium tyrobutyricum for Butyl Butyrate Production on Xylose and Shrimp Shell Waste.

Microbial conversion of agri-food waste to valuable compounds offers a sustainable route to develop the bioeconomy and contribute to sustainable biorefinery. Clostridium tyrobutyricum displays a series of native traits suitable for high productivity conversion of agri-food waste, which make it a promising host for the production of various compounds, such as the short-chain fatty acids and their derivative esters products. In this study, a butanol synthetic pathway was constructed in C. tyrobutyricum, and then efficient butyl butyrate production through in situ esterification was achieved by the supplementation of lipase into the fermentation. The butyryl-CoA/acyl-CoA transferase (cat1) was overexpressed to balance the ratio between precursors butyrate and butanol. Then, a suitable fermentation medium for butyl butyrate production was obtained with xylose as the sole carbon source and shrimp shell waste as the sole nitrogen source. Ultimately, 5.9 g/L of butyl butyrate with a selectivity of 100%, and a productivity of 0.03 g/L·h was achieved under xylose and shrimp shell waste with batch fermentation in a 5 L bioreactor. Transcriptome analyses exhibited an increase in the expression of genes related to the xylose metabolism, nitrogen metabolism, and amino acid metabolism and transport, which reveal the mechanism for the synergistic utilization of xylose and shrimp shell waste. This study presents a novel approach for utilizing xylose and shrimp shell waste to produce butyl butyrate by using an anaerobic fermentative platform based on C. tyrobutyricum. This innovative fermentation medium could save the cost of nitrogen sources (~97%) and open up possibilities for converting agri-food waste into other high-value products.

Aplikasi Edible Coating dari Limbah Kulit Udang dengan Aditif Asap Cair untuk Kemasan Sosis Sapi Antibakteri Ramah Lingkungan

Edible coating is a food preservation technique by coating using antimicrobial substances which can inhibit the growth of bacteria. This research aims to develop an edible coating from shrimp shell waste with liquid smoke additives as antibacterial packaging for processing beef sausages. Chitosan is made in three stages, namely demineralization, deproteination and deacetylation. Beef sausages coated with edible coating were tested using organoleptic and antibacterial tests. The results of this research showed that the highest degree of deacetylation of chitosan was found in the variable concentration of sodium hydroxide (NaOH) 55% with a degree of deacetylation value of 93.59%. The water and protein content in beef sausages coated with edible coating with liquid smoke showed values of 52.45% and 12.65% on the 7th day. This is in accordance with the Indonesian National Standards (SNI). Coating beef sausages using edible coating from 2% chitosan with 8% liquid smoke solvent has antimicrobial properties because in the antibacterial test a clear zone appeared on the beef sausages coated with edible coating.

Optimization of Wall Materials for Astaxanthin Powder Production from Shrimp Shell Extract Using Simplex Lattice Mixture Design

Shrimp shell waste is an attractive source of value-added bioactive-rich by-products. Shrimp shell extract containing astaxanthin was recovered by solvent extraction method (petroleum ether/acetone/water with a ratio of 15 : 75 : 10) and ultrasound process (amplitude 20% for 15 min at 35°C). The extract was then encapsulated by freeze-drying using wall materials such as maltodextrin (with the dextrose equivalent (DE) of 7 (MD7) and 20 (MD20)) and modified starch (Hi-Cap 100) incorporated at different ratios. Simplex lattice with augmented axial points in the mixture design was applied for the optimization of wall material. The optimal wall materials were 29.4% (MD7), 34.0% (Hi-Cap 100), and 36.6% (MD20), with encapsulation yield (Y) of 94.6%, encapsulation efficiency (EE) of 91.8%, astaxanthin content (Ast) of 46.1 μg/g DW, and DPPH scavenging capacity of 64.0%, respectively. The optimized microcapsules had spongy morphology and brittle and flaky mass. The degradation kinetics of bioactive astaxanthin in UV light was evaluated and found to follow first-order reaction kinetics. The microcapsules obtained under optimal wall composition exhibited the highest UV light stability with half-life values of 76.8 h, demonstrating a high stability.

Rigidity-toughness coupling in architected composite materials for enhanced impact resistance

In recent decades, architected composite materials have received increasing attention due to its promising potential in improving the impact resistance performance compared with bulk materials. Some ingenious microstructures of biomaterials can enlighten the design of novel architected composite materials, such as nacre, conch shell and dactyl club of mantis shrimp, which have been extensively applied. Here, in order to further enhance the impact resistance of architected composite materials, hybrid architectures are proposed based on nacre-like brick-mud and sponge-like lamellar architectures. Then, their impact resistance performances and mechanism are investigated by combining experiment with finite element simulation. The results show that through positive hybrid design inspired of the dactyl club, the lamellar bottom makes the hybrid architecture retain excellent toughness, and the brick-mud top guarantees large flexural stiffness, thereby achieving rigidity-toughness coupling and boosting the energy absorption dramatically. Moreover, as the decline of volume ratio of soft phases within and between brick-mud layers, the energy absorption of brick-mud architecture gradually increases owing to the rising damage resistance. Further, the rigidity-toughness coupled effect can be optimized by positively hybridizing multiple architectures with larger variation in flexural stiffness and toughness, even achieving 375 % improvement in energy absorption compared with the basic brick-mud architecture.

Pretreatment of shrimp shells with an acidic deep eutectic solvent system for chitin extraction and its enhanced performance as a carrier for immobilized lipase

Existing methods for chitin extraction usually produce substantial waste, which poses ecological hazards. Natural deep eutectic solvent (NADES) offers a promising one-step pretreatment alternative, replacing the resource-intensive demineralization (DM) and deproteinization (DP) process. Hence, in this study, the influence of various acidic NADES, on achieving a simplified one-step DM and DP in the chitin extraction process was investigated. The study yielded chitin with 87.73 % purity, and microstructural analysis showed that NADES pretreatment minimally affected chitin quality without deacetylation. In addition, chitin extracted using choline chloride-oxalic acid as a carrier displayed excellent performance in the immobilization of Geobacillus thermocatenulatus lipase 2 (GTL2) because of obvious Ca2+ activation effect. This process contributed to enhancement of immobilized enzyme activity. The immobilized GTL2 showed excellent hydrolytic capabilities, with its highest activity reaching 547.80 ± 20.62 U/mg, significantly better than the five commercial lipases that exhibited <40 % of the enzyme activity. Furthermore, the hydrolytic capacity of immobilized GTL2 was notably high for 4-nitrophenyl butyrate, measuring 935.47 ± 51.60 U/mg. This study provided a constructive approach for the one-step pretreatment of shrimp shells with organic acid-based NADES to isolate and purify chitin and its potential application as an immobilized carrier to enhance enzyme activity.

Growth and yield performance of Sweet Pepper varieties by exogenous application of chitosan-raw-material (Shrimp shell powder)

Growth and yield performance of Sweet Pepper varieties by exogenous application of chitosan-raw-material (Shrimp shell powder)

Designing Lightweight 3D-Printable Bioinspired Structures for Enhanced Compression and Energy Absorption Properties.

Recent progress in additive manufacturing, also known as 3D printing, has offered several benefits, including high geometrical freedom and the ability to create bioinspired structures with intricate details. Mantis shrimp can scrape the shells of prey molluscs with its hammer-shaped stick, while beetles have highly adapted forewings that are lightweight, tough, and strong. This paper introduces a design approach for bioinspired lattice structures by mimicking the internal microstructures of a beetle's forewing, a mantis shrimp's shell, and a mantis shrimp's dactyl club, with improved mechanical properties. Finite element analysis (FEA) and experimental characterisation of 3D printed polylactic acid (PLA) samples with bioinspired structures were performed to determine their compression and impact properties. The results showed that designing a bioinspired lattice with unit cells parallel to the load direction improved quasi-static compressive performance, among other lattice structures. The gyroid honeycomb lattice design of the insect forewings and mantis shrimp dactyl clubs outperformed the gyroid honeycomb design of the mantis shrimp shell, with improvements in ultimate mechanical strength, Young's modulus, and drop weight impact. On the other hand, hybrid designs created by merging two different designs reduced bending deformation to control collapse during drop weight impact. This work holds promise for the development of bioinspired lattices employing designs with improved properties, which can have potential implications for lightweight high-performance applications.

Biochemical and physicochemical properties of shrimp (Pandalus borealis) compounds after compact filter press process

AbstractBackgroundMost of the shrimp side streams are discarded due to the lack of appropriate processing techniques/methodology for their utilization, which is not only a loss of potentially valuable compounds, but also leads to environmental pollution. The study aimed to employ a mechanical filter press to separate the liquid called press juice (PJ) and the solid named press cake (PC) fraction from shrimp head and shell (H&amp;S).ResultsThe proximate composition was performed, including amino acids analysis, protein content, fatty acids, and the main volatile compounds. In the whole shrimp (WS), the average values of protein, lipid, dry matter, and ash content were recorded at 14.7%, 2.9%, 21.1%, and 4.8%, respectively. The protein percentage reached 10.1% in H&amp;S, indicating considerable amount of protein leftover in the shrimp side streams (p &lt; 0.05). The major PUFAs in WSs' sample were Eicosapentaenoic acid (EPA) (8.8%) and Docosahexaenoic acid (DHA) (7.8%). Furthermore, the values of EPA and DHA a showed nearly two‐folded increase after peeling and filter‐pressing, PC sample. Total amino acids in the WS, H&amp;S, PJ, and PC samples were found to be 94.6, 67.7, 22.2, and 76.6 mg/g, respectively. From the nutritional point of view, non‐essential amino acids represented higher values (13.2%–56.9%) compared to essential amino acids (9.0%–37.6%). The major components of 5′‐neucleoitides in WS sample were in order of guanosine‐5′‐diphosphate (GDP) ≫ hypoxanthine (HYP) &gt; inosine‐5′‐monophosphate (IMP) ≫ adenosine‐5′‐monophosphate (AMP) &gt; adenosine‐5′‐diphosphate (ADP) with values of 684.4, 293.6, 201.4, 25.6 and 16.2 μg/g sample, while no inosine (INO), guanosine‐5′‐monophosphate (GMP), and guanosine‐5′‐triphosphate (GTP) were detected. Equivalent umami concentration (g MSC/100 g) was recorded as 0.63, 0.07 for WS and H&amp;S samples and 0.015 for PJ sample, which indicates a significant drop from the shrimp raw material toward the side streams. Most volatile compounds belonged to alkenes followed by alkanes groups.ConclusionThis work showed the possibility to employ the filter press machine to obtain PJ and PC from shrimp H&amp;S, after peeling processing. The fractions present an interesting nutritional composition and value.

Physical and Chemical Characteristics of Liquid Organic Fertilizer from Shrimp Shell Waste and Old Coconut Water

The rapid growth of people and industry generates organic waste of 50-60% of production materials. These wastes can be used for agriculture, as human awareness of healthy consumption causes agriculture to start using organic materials. Organic waste from industry in the form of shrimp shells and old coconut water can be used as organic fertilizer for plant growth and development. This study aims to examine the dynamics of reactions that occur during the process of making organic fertilizer and test the physical and chemical quality of the resulting organic fertilizer. This research has a combination design of 2 factors. The first factor is the fermentation method (F) which consists of 2 levels, namely: F1 = container with air hose (aerobic), F2 = tightly closed container (anaerobic). The second factor is the organic fertilizer raw material (L) which consists of 3 levels, namely: L1 = shrimp shell waste, L2 = old coconut water, L3 = shrimp shell waste + old coconut water. The results showed on the physical characteristics, aerobic fermentation treatment is faster to produce organic fertilizer than anaerobic, and the speed of producing organic fertilizer is also influenced by the characteristics of raw materials. Wheareas based on the chemical properties, all treatments have not met the Indonesian national standards, but there are several chemical components that meet such as pH, C-organic and N-total. The treatments that are close to the standard are F1L1 and F1L3 treatment for N-total, F1L2 and F2L2 for C-organic.

Fortification of Shrimp Shell Flour as a Source of Calcium on the Preference Level of Bread

This research aim was to find the most preferred percentage of shrimp shell flour fortification on white bread. This research used an experimental method with 20 semi-trained panelists and 5 treatments of shrimp shell flour percentages which were 0%; 2,5%; 5%; 7,5%; and 10%. The parameters in this research were yield of shrimp shells, bread volume development, and calcium content which were analyzed with a comparative descriptive method; and preference level which was analyzed using the Friedman test. Fisheries Product Processing Laboratory, Faculty of Fisheries and Marine Science and Test Service Laboratory, Faculty of Agro-Industrial Technology, Padjadjaran University, between January and June 2023. Yield and volume development were tested by the ratio of the mass of shrimp shells flour and shrimp shells (yield test) and dough volume and white bread loaf (volume development test) times 100%. The Preference test used an organoleptic test with each panelist being given a test sheet to test 5 treatments of white bread fortified with shrimp shell flour and to test their preference level on 4 characteristics; which were color, aroma, texture, and taste. Calcium content was tested using the atomic absorption spectrophotometer method on the control treatment (0%) and the most preferred treatment. Yield result from shrimp shell flour was 27.8% (139 gr) from its initial mass (500 gr). Volume development of white bread showed decreases in volume with each treatment from 136.433% to 111.504%. The most preferred fortification of shrimp shell flour on white bread was treatment 2.5% with an alternative value of 7.22 and characteristic value of color 9, aroma 7, taste 7, and texture 7, which means overall still preferred. The calcium content within treatment 2.5% was 30.095 mg/100gr which is significantly higher than the calcium of treatment 0% (1.465 mg/100gr) and could assist humans meet their calcium needs.

Evaluation of Encapsulated Astaxanthin from White Shrimp Shells (Litopenaeus vannamei) on Hepatotoxicity

Recent advances in astaxanthin encapsulation have been reported, but hepatotoxic effect remains unclear. The present investigation therefore aimed to examine the effects of encapsulated astaxanthin from white shrimp shells (Litopenaeus vannamei) on liver toxicity. Wistar rats were divided into 6 groups as control (C), and receiving vitamin E (VE), astaxanthin commercial (AC), astaxanthin extracted from white shrimp shells (AE), astaxanthin encapsulation into powder form (AP), and blank powder (BP). The evaluation of liver in response to astaxanthin administration was then assessed in terms of biochemical parameters and histopathological features. Liver enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), showed no significant differences among all groups of treatment. Histopathological study showed no abnormal changes on liver tissue including hepatic inflammation. Our data demonstrated that astaxanthin encapsulation did not increase the expression of NF-ҡB nuclear translocation and CYP2E1 in comparison with the control group. Additionally, in this study, the consumption of astaxanthin and vitamin E resulted in a reduction in the oxidative stress index (OSI), while the levels of antioxidant enzymes, including glutathione peroxidase (GPx) and superoxide dismutase (SOD), were significantly increased compared to the control group. Our data suggested that astaxanthin encapsulation does not cause hepatic toxicity, contributing useful information in the applications of astaxanthin encapsulation technology.

Surface defects due to bacterial residue on shrimp shell

The changes in the surface chemistry and morphological structure of chitin forms obtained from shrimp shells (ShpS) with and without microorganisms were evaluated. Total mesophilic aerobic bacteria (TMAB), estimated Pseudomonas spp. and Enterococcus spp. were counted in Shp-S by classical cultural counting on agar medium, where the counts were 6.56 ± 0.09, 6.30 ± 0.12, and 3.15 ± 0.03 CFU/g, respectively. Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM)/Energy dispersed X-ray (EDX) were used to assess the surface chemistry/functional groups and morphological structure for ChTfree (non-microorganism), and ChTmo (with microorganisms). ChTfree FTIR spectra presented a detailed chitin structure by OH, NH, and CO stretching vibrations, whereas specific peaks of chitin could not be detected in ChTmo. Major differences were also found in SEM analysis for ChTfree and ChTmo. ChTfree had a flat, prominent micropore, partially homogeneous structure, while ChTmo had a layered, heterogeneous, complex dense fibrous, and lost pores form. The degree of deacetylation was calculated for ChTfree and ChTmo according to FTIR and EDX data. The results suggest that the degree of deacetylation decreases in the presence of microorganisms, affecting the production of beneficial components negatively. The findings were also supported by the molecular docking model.

Adsorbents from rice husk and shrimp shell for effective removal of heavy metals and reactive dyes in water

Widespread contamination by heavy metals (HMs) and dyes poses a major health risk to people and ecosystems requiring effective treatment. In this work, rice husk (RH) and shrimp shells were extracted to obtain amorphous silica and chitosan, respectively, which were utilized to produce nano-chitosan-coated silica (NCCS). To ensure the stability of the nanoparticles, silica was freeze-dried after being coated with nano-chitosan. Functional groups (–NH2, –OH, P]O) from chitosan nanoparticles (CNPs) were introduced to the surface of silica during this process. Dyes such as brilliant green (BG), methylene blue (MB) and reactive brown (RB) as well as HMs (Cr6+, Pb2+, Cd2+, Ni2+) were removed by adsorbents. CNPs showed the highest adsorption capacity for RB (59.52 mg/g) among dyes and Cr6+ (42.55 mg/g) among HMs. CNPs showed the highest adsorption capacity for HMs among different adsorbents. Although NCCS and CNPs showed similar adsorption capabilities for HMs and dyes, NCCS showed the best stability. The adsorption performance decreased as RB > Cr6+ > MB > BG > Pb2+ > Cd2+ > Ni2+. The adsorption reactions followed both pseudo-first-order and second-order kinetics, and was spontaneous from thermodynamic analysis. In summary, the waste-derived adsorbents demonstrated excellent potential for removing HMs and dyes from water, while supporting effective management solid waste.