Lobster Shell Research Articles

Turning Trash to Treasure: The Influence of Carbon Waste Source on the Photothermal Behaviour of Plasmonic Titanium Carbide Interfaces.

Pyrolysis of carbonaceous waste materials has emerged as an effective recycling method to generate value-added products. In addition to producing pyrolytic oil and gas, the thermal degradation process yields solid pyrolytic char, which can be further processed. In this study, local waste materials, birch wood residue, Japanese knotweed stems, spent coffee grounds, tire rubber, and lobster shells were assessed for their potential to form pyrolytic char. After a simple acid treatment, many of these chars were successfully incorporated into solid-state synthesis of plasmonic titanium carbide (TiC) nanoparticles (NPs). Each char exhibited unique physical and chemical properties, which were leveraged to synthesize TiC NPs with distinct characteristics. To evaluate the plasmonic behavior of these TiC samples, solar-driven desalination experiments were performed. Notably, TiC derived from tire rubber demonstrated a high broadband absorbance and achieved a solar-to-vapor generation efficiency of 95%, corresponding to an evaporation rate of 1.40 ± 0.01 kg m-2 h-1 under one-sun illumination. This performance is the highest among all chars tested and ranks among the top reported values in the literature. Additionally, the evaporation interface maintained its performance over multiple cycles and under highly hypersaline conditions.

Electrospun polyvinyl alcohol nanofiber scaffolds incorporated strontium-substituted hydroxyapatite from sand lobster shells: synthesis, characterization, and in vitro biological properties

The paper describes the synthesis of hydroxyapatite (HAp) and strontium-substituted hydroxyapatite (SrHAp) from sand lobster shells by a hydrothermal method. The HAp and SrHAp were incorporated into the polyvinyl alcohol (PVA) nanofiber scaffold through the eletrospinning method. The scaffolds were incorporated with 5wt% of hydroxyapatite (HAp), 5wt%, 10wt%, and 15% of SrHAp. The physicochemical, mechanical, and in vitro biological properties of the scaffold were evaluated. The incorporation of HAp or SrHAp was evidenced by the diffraction patterns and the phosphate functional groups related to HAp. The morphological results showed the decrement of fiber diameter in line with the increased SrHAp concentration. A tensile test was conducted to investigate the mechanical properties of the scaffolds, and the results showed that the scaffolds perform poorly at a higher SrHAp concentration because of exceeding agglomeration levels. The PVA/SrHAp15 performed the best antibacterial activity against E. coli and S. aureus with an inhibition zone of (15.2 ± 0.2) and (14.5 ± 0.8), respectively. The apatite formation was more abundant in PVA/SrHAp10 after immersion in a simulated body fluid (SBF). Cell viability results showed that the scaffold enabled the osteoblast cells to grow and proliferate. The biocompatibility of HAp and SrHAp resulted in the enhancement of cell adhesion. Based on all tests, the PVA/SrHAp 10 scaffold shows a strong candidate for further in vivo studies.

Lobster Shells: A Sustainable Source of Biogenic Materials and Their Extractions and Applications

Lobster shell derivatives have the potential to be a valuable resource for sustainable development and innovation. This article outlines the methods and research advancements for isolating minerals and chitosan from lobster shells and converting them into functional materials. The different types of methods of extraction of major components are discussed in detail Additionally, it discusses their applications in diverse fields. This article gives a comprehensive summary of the present state of research in this field. Also, it presents a future research outlook, highlighting areas for further investigation and advancements in the field.

PSV-29 In vitro digestibility and in situ degradability of lobster and mixed crab shell waste material

Abstract The objective of this research was to determine the in situ and in vitro degradability of lobster shell waste meal (LM) and crab shell waste meal (CM). Lobster and crab harvest are major industries within the New England states and the Maritime provinces. Harvest of the American lobster amounts to 54,643 tons caught and processed in 2020 in the New England states. The Atlantic Red Crab annual quota is around 1,814 tons. The Jonah Crab amounts to 5,725 tons. Due to the significant harvest, there is a resulting increase in byproducts and wastes at processing facilities providing potential feedstuffs for cattle. For both experiments, LM and CM were compared with soybean (SBM) and blood meals (BM). In experiment 1, 0.5 g of each meal were added to an artificial rumen incubator (Daisy, Ankom technologies) and DM degradability over 48 h was measured. In experiment 2, ruminally-cannulated Holstein cows (n = 4) in a 4 × 4 Latin square, had 5 g of sample were placed in Dacron bags in the dorsal rumen. Bags were in duplicate and removed at 2, 4, 8,12, 24, and 48 h time points. Eight bags were removed at 12 h for use in the in vitro intestinal degradability measurement using the modified three-step technique. Contrasts were: SBM vs. BM+LM+CM (SBM vs others), BM vs. LM+CM, and LM vs. CM. In experiment 2, 0 h bags served as a determination of fraction A, while the 48 h bags served as fraction C. Fraction B = 100% - (fraction A + fraction C). Degradation rate (kd) was calculated by converting % CP degraded from 2 to 24 h to Ln and then calculating the slope. In experiment 1, DM degradation was 45.8, 43.8, 76.4 and 100.1 % for SBM, BM, LM, and CM respectively; SBM vs others (P < 0.01), BM vs. LM + CM (P < 0.01), and no difference between LM vs. CM. Fraction A (CP) was 9.9, 8.1, 4.2, and 4.8% respectively; with SBM vs. others (P < 0.03), BM vs. LM+CM (P < 0.01), and no difference between LM vs CM. Fraction B (CP) was 76.2, 62.2, 28.9, and 42.6% respectively; with SBM vs. others (P < 0.01), BM vs. LM + CM (P < 0.01), and LM vs. CM (P < 0.10). Fraction C (CP) was 4.41, 30.8, 46.8, and 37.5% respectively; with SBM vs. others (P < 0.01), BM vs. LM + CM (P < 0.03), and LM vs. CM (P < 0.08). Intestinal CP digestibility was 56.2, 64.7, -5.83, and 10.5% respectively, with SBM vs others (P < 0.01), BM vs LM+CM (P < 0.01), and no difference between LM and CM. Results of these studies indicated that LM and CM may have some benefits in cattle diets, but feeding studies should be conducted.

Comparative efficiency of different polyol-based deep eutectic solvents for chitin extraction from lobster shells

In this study, deep eutectic solvent (DES) prepared from choline chloride, lactic acid, and one of the four polyols (ethylene glycol, glycerol, xylitol, and sorbitol) were compared and assessed for their effectiveness in extracting chitin from lobster shells. Our results revealed that as the number of hydroxyl groups in polyols increased, the hydrogen bond network within the DESs became denser. However, this led to a corresponding increase in viscosity, which impacted the efficiency of chitin extraction. Among all prepared DESs, choline chloride-lactic acid/glycerol (CCLaGly) exhibited superior extractive ability, resulting in the extraction of pure chitin from lobster shells. The purity, crystallinity, and molecular weight of the extracted chitin using CCLaGly DES were comparable to those of chemically-isolated chitin, with purity reaching 94.76 ± 0.33 %, crystallinity at 78.78 %, and a molecular weight of 655 kDa. Additionally, the physicochemical properties of the DES-extracted chitins were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. This study conducted a comparative analysis of polyol effects on chitin extraction from lobster shells, thereby opening a promising avenue for the utilization of various crustacean shells in sustainable biomaterial production.

Physiological impacts of climate change on juvenile American lobster Homarus americanus (Decapoda: Astacidea: Nephropidae), a commercially important species

Abstract The American lobster, Homarus americanus, H. Milne Edwards, 1837 is an ecologically, economically, and culturally valuable marine resource for the coastal communities in the Gulf of Maine. Lobsters in the Gulf of Maine are experiencing the effects of rapid warming and acidification due to climate change. Lobster shells are comprised of chitin with precisely precipitated minerals (calcite, amorphous calcium carbonate, and carbonate apatite) that provide structural integrity to the shell and protection against predators and microbial intrusion. We examined the combined effects of ocean warming and acidification on shell mineralogy, epibiont abundance, and growth in early benthic juveniles. Lobsters were grown under six different temperature/pCO2 treatment conditions over 52 days (three replicates per treatment) aligned with environmentally relevant as well as predicted future extremes. Elevated pCO2 and temperature led to a decrease in shell calcium and magnesium content, suggesting that these environmental stressors inhibit shell biomineralization. There was an interactive effect of the stressors on epibiont abundance with the probability of epibiont coverage increasing with increasing pCO2 and temperature. Elevated pCO2 alone was significantly correlated (P = 0.002) to decreased growth, but only for female lobsters. Ocean acidification and warming significantly affect shell integrity in juvenile lobster, increasing risk to injury and disease with potential downstream consequences for the lobster fishery.

Upcycling of seafood side streams for circularity.

The upcycling of seafood side streams emerges as a crucial facet in the quest for circularity within the food industry, surpassing other food sources in its significance. Seafood side stream plays an indispensable role in global food security and human nutrition. Nevertheless, losses ensue throughout the seafood supply chain, resulting in substantial waste generation. These underutilized seafood by-products contain valuable resources like edible proteins and nitrogenous compounds. Projections indicate that fishery products' utilization for human consumption will soar to 204 MT by 2030. Yet, the industry annually generates millions of tonnes of waste, predominantly from crab, shrimp, and lobster shells, leading to environmental impacts due to COD and BOD issues. A five-tier circular economic model offers a framework to manage seafood side-streams efficiently, with applications spanning pharmaceuticals, food production, animal feed, fertilizers, and energy fuel, thereby maximizing their potential and reducing waste in line with sustainability goals.

Nanofibrous electrospun scaffold doped with hydroxyapatite derived from sand lobster shell (Panulirus homarus) for bone tissue engineering.

Healing of significant segmental bone defects remains a challenge, and various studies attempt to make materials that mimic bone structures and have biocompatibility, bioactivity, biodegradability, and osteoconductivity to native bone tissues. In this work, a nanofiber scaffold membrane of polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP)/chitosan (CS) combined with hydroxyapatite (HAp) from sand lobster (SL; Panulirus homarus) shells, as a calcium source, was successfully synthesized to mimic the nanoscale extracellular matrix (ECM) in the native bone. The HAp from SL shells was synthesized by co-precipitation method with Ca/P of 1.67 and incorporated into the nanofiber membrane PVA/PVP/CS synthesized by the electrospinning method with varying concentrations, i.e. 0, 1, 3, and 5% (w/v). Based on the morphological and physicochemical analysis, the addition of HAp into the nanofiber successfully showed incorporation into the nanofiber with small agglomeration at HAp concentrations of 1, 3, and 5% (w/v). This led to a smaller fiber diameter with higher concentration of Hap, and incorporating HAp into the nanofiber could improve the mechanical properties of the nanofiber closer to the trabecula bone. Moreover, in general, swelling due to water absorption increases due to higher hydrophilicity at higher HAp concentrations and leads to the improvement of the degradation process and protein adsorption of the nanofiber. Biomineralization in a simulated body fluid (SBF) solution confirms that the HAp in the nanofiber increases bioactivity, and it can be seen that more apatite is formed during longer immersion in the SBF solution. The nanofiber PVA/PVP/CS HAp 5% has the most potential for osteoblast (MC3T3E1) cell viability after being incubated for 24 h, and it allowed the cell to attach and proliferate. Additionally, the higher HAp concentration in the nanofiber scaffold membrane can significantly promote the osteogenic differentiation of MC3T3E1 cells. Overall, the PVA/PVP/CS/HAp 5% nanofiber scaffold membrane has the most potential for bone tissue engineering.

Polyvinyl alcohol/Polyvinylpyrrolidone/Chitosan Nanofiber Scaffold with Hydroxyapatite from Sand Lobster Shells (Panulirus homarus) for Bone Tissue Engineering

In this work, nanofiber scaffold membrane polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP)/Chitosan (CS)/hydroxyapatite (HAp) from sand lobster (SL; Panulirus homarus) shells have successfully synthesized to mimic the extracellular matrix (ECM) nanoscale in the native bone. HAp was synthesized by co-precipitation method with Ca/P was 1.67, then nanofiber membrane PVA/PVP/CS/HAp was synthesized by electrospinning method. Nanofiber solution was prepared from PVA 10% (w/v) polymer solution that dissolved in the distilled water, then the PVP/CS 15% (w/v) polymer solution was dissolved in acetic acid 1% (v/v) separately. The PVA polymer solution and PVP/CS solution were mixed with a ratio of 8.5: 1.5 (v/v). HAp dispersed into mixture solution with variation concentration 0, 1, 3, and 5 wt%. The composite solution was put into a 10 ml syringe with a hole diameter = 0.5 mm. Electrospinning was carried out at a 10 kV voltage, the flow rate at 0.1 ml/h, and the distance between the collector to the tip was 12 cm. Nanofiber scaffold membrane was characterized using SEM, FTIR, and XRD. The addition of HAp into the fiber showed incorporation into nanofiber with small agglomeration in the concentration of HAp at 1, 3, and 5 wt%. Based on the physicochemical analysis, the nanofiber scaffold PVA/PVP/CS/HAp 5 wt% with a fiber diameter of 0.328 ± 0.049 μm has the most potential to be used for bone tissue engineering.

Utilization of Chitosan from Fresh Water Lobster (Cherax quadricarinatus) Shells in Anti-Acne Gel Preparations

Cutibacterium acnes is one of the bacteria that cause acne on the face. Freshwater crayfish (Cherax quadricarinatus) shells have been abandoned and are not used by the community; thus, their shells are processed into economically valuable compounds such as chitosan. Chitosan has antibacterial characteristics that can inhibit acne bacterial development. The purpose of this study is to see if chitosan derived from crayfish shells may be stable in the form of an anti-acne gel and has antibacterial action against Cutibacterium acnes. Anti-acne gel was made from crayfish shells at concentrations of 2, 4 and 6 %, then gel formulations were evaluated and antibacterial efficacy against Cutibacterium acnes germs was tested. Chitosan produced by freshwater lobster shells was 68.75 %. The results of the test of freshwater crayfish shells against Cutibacterium acnes revealed that the average diameter of the inhibition was 6.34 mm at a concentration of 2 %, 6.57 mm at a concentration of 4 % and 6.90 mm at a concentration of 6 %; thus, a concentration of 6 % has the best inhibition. According to the organoleptic test, there was no change in shape or color. According to the homogeneity test, there are no lumps or coarse grains. According to the spreadability test, all preparations were within a 56 cm range. The adhesion test shows a satisfactory adhesion time of more than 1 s. The pH test revealed that all preparations were within the normal skin pH range, indicating that the recipe satisfied the specifications. Anti-acne gel prepared from the shell of a freshwater crayfish displays antibacterial action against Cutibacterium acnes as a cause of acne, with an inhibitory diameter of 6.11 mm at 2 % concentration, 6.8 mm at 4 % concentration and 7.11 mm at 6 % concentration. The diameter of the inhibitory zone in the positive control was 11.9 mm. HIGHLIGHTS Freshwater crayfish shells against Cutibacterium acnes revealed that the average diameter of the inhibition was 6.34 mm at a concentration of 2 %, 6.57 mm at a concentration of 4 %, and 6.90 mm at a concentration of 6 %; thus, a concentration of 6 % has the best inhibition Anti-acne gel prepared from the shell of a freshwater crayfish displays antibacterial action against Cutibacterium acnes as a cause of acne, with an inhibitory diameter of 6.11 mm at 2 % concentration, 6.8 mm at 4 % concentration, and 7.11 mm at 6 % concentration. The diameter of the inhibitory zone in the positive control was 11.9 mm GRAPHICAL ABSTRACT

Chemical extraction of chitin from American lobster (Homarus americanus) shells optimized through response surface methodology

Chitin extraction from the shells of American lobsters (Homarus americanus) was optimized through the use of response surface methodology (RSM). The demineralization step was optimized to minimize the ash content of shell samples and the deproteination step was optimized to minimize the protein content of the chitin product. At a laboratory scale, one set of optimized conditions for the demineralization step was 7.35 % w/w acetic acid at a 40 mL/g of powdered lobster shell ratio for 15 min; this lowered the ash content from 39.62 % to 0.41 ± 0.08 %. A set of optimized conditions for the deproteination step at a similar scale was 4 % w/w sodium hydroxide at a 43 mL/g demineralized shell ratio heated to 95 °C for 83 min. These conditions were indicated to entirely remove protein from the resultant chitin. Average yields under optimized conditions were 23.43 ± 1.75 % for demineralization and 30.33 ± 0.02 % for deproteination, though a demineralization reaction with larger biomass input had a higher yield at 40.31 %.

Exploring biological activity and In-vitro anticancer effects of a new biomaterial derived from Schiff base isolated from Homarus americanus (Lobster) shell waste

In this study, chitin, a valuable biopolymer material, was extracted from lobster (Homarus americanus) shell waste using a chemical method. Afterward, the biopolymer was added to a mixture of the precursor (β-diketone and acidhydrazide) and monochloroacetic acid to prepare the biomaterial/hydrazone-based O-carboxymethyl chitosan Schiff base compounds. The prepared biomaterials were studied for potential biological applications, such as antimicrobial, antioxidant, wound healing, cytotoxicity, phosphate inhibition, and anticancer studies. The inhibition of alkaline phosphatase (ALP) enzyme was recorded using UV–Vis spectrophotometry. Wound healing studies of biopolymer materials and their derivatives were studied to RAW 264.7 (murine monocyte / macrophage) cells by scratch wound healing analysis. Additionally, using MTT analysis the in-vitro, anticancer efficacies (cell viability/cell proliferation/cytotoxicity) were conducted for SK-MEL-28 (human melanoma cells), MDA-MB-231 (human breast cancer cells), and the U87 (human glioma brain cells). The half maximal inhibitory concentration (IC50) values for SK-MEL-28 cells had 0.71 μg/mL at 24 h, and was a potent activity as compared to U-87 (35.98 μg/mL) and MDA-MB-231 (18.31 μg/mL) cells. The water-soluble / swelling nature of prepared biomaterials is utilized in the bio-ink formulation by the incorporation of the biopolymers such as cellulose, sodium alginate, gelatin, hyaluronic acid, and laponite RDS for potential biomedical applications.

Long-read sequencing reveals the shell microbiome of apparently healthy American lobsters Homarus americanus from Atlantic Canada.

The shell microbial community of lobsters-a key factor in the development of epizootic shell disease (ESD)-is still insufficiently researched in Atlantic Canada and many knowledge gaps remain. This study aimed to establish a baseline description and analysis of the shell microbiome of apparently healthy lobsters from four locations in the region. More than 180 lobster shell swab samples were collected from New Brunswick, Nova Scotia and Prince Edward Island (PEI). PacBio long-read 16S rDNA sequencing and bioinformatic analyses in QIIME2 identified the shell-associated bacteria. The shell microbiome of healthy lobsters consisted mainly of the bacterial classes Gammaproteobacteria, Saprospiria, Verrucomicrobiae, Alphaproteobacteria, Flavobacteriia, Acidimicrobiia and Planctomycetia. The microbial composition differed regionally and seasonally, with some classes showing decreased or increased relative abundances in the PEI samples as well as in the winter and spring samples in Nova Scotia. The core shell microbiome included potentially pathogenic as well as beneficial bacterial taxa, of which some were present only in certain regions. Bacterial taxa that have previously been associated with ESD were present on healthy lobsters in Atlantic Canada, but their frequency differed by location, sampling time, and moult stage. This study indicated that geographical and seasonal factors influenced the shell microbiome of apparently healthy lobsters more than host factors such as sex, size, and moult stage. Our results provide valuable reference microbial data from lobsters in a disease-free state.

Porous scaffold hydroxyapatite from sand lobster shells (Panulirus homarus) using polyethylene oxide/chitosan as polymeric porogen for bone tissue engineering.

The hydroxyapatite (HAp; Ca10 (PO4 )6 (OH)2 )) has good biocompatibility, bioactivity, and osteoconductivity as a bone implant because the main inorganic mineral of human bone is HAp. The use of scaffold HAp from biogenic resources that contain high calcium and polymer as a pore forming agent to support bone growth is a longstanding area of interest. In this study, porous scaffolds based on HAp were synthesized from sand lobster (SL; Panulirus homarus) shells as a source of calcium using the porogen leaching method with polyethylene oxide (PEO) and chitosan (Chs) as polymeric porogen. The present study aims to synthesize HAp derived from SL shells and evaluate the effect variations of PEO on the physicochemical properties of the scaffold and cytotoxicity in cell viability assay. Briefly, the SL shell powder was calcinated with temperature variations of 600°C, 800°C, and 1000°C for 6 h. Based on the characterization, it was shown that 1000°C was the optimum calcination temperature for SL shells to synthesize HAp using the precipitation method. The characterization results of HAp using energy dispersive x-ray (EDX) revealed that the molar ratio of Ca/P was 1.67. The Fourier transform infrared (FTIR) and x-ray diffractometer (XRD)spectral patterns indicated that HAp had been successfully synthesized with minor β-tricalcium phosphate (β-TCP), a calcium phosphate with high biocompatibility. Porous scaffolds were synthesized by varying the concentration of PEO at 0, 5, 10, and 15 wt %. Physicochemical analysis revealed that a higher concentration of PEO affected decreased crystallinity and compressive strength, but on the other hand, the porosity and pore sizes increased. Based on the physicochemical analysis, the synthesized porous scaffold showed that HAp/PEO/Chs 15 wt % had the most potential as a scaffold for biomedical applications. MTT Assay, after 24 h incubation, revealed that the scaffold was safe for use at low concentrations on the MC3T3E1 osteoblast cells, with a percentage of cell viability of 83.23 ± 3.18% at 23.4375 μg/mL. Although the cell viability decreased at higher concentrations, the HAp/PEO/Chs 15 wt % scaffold was cytocompatible with the cells. Thus, in the present study, HAp/PEO/Chs 15 wt % was the best scaffold based on pore structure, chemical composition, mechanical and crystalographic properties and cell viability.

Degradation of marine crustacean shell wastes through single-stage co-fermentation using proteolytic and chitinolytic bacteria.

Management of crustacean shell waste (SW) through an eco-friendly technique is an environmental obligation to control pollution. The present study showed a novel approach through the simultaneous application of proteolytic and chitinolytic bacteria to effectively degrade unprocessed crustacean SW. For this, the bacteria with concurrent chitinolytic and proteolytic activity (Bacillus subtilis, Priestia megaterium, or Bacillus amyloliquefaciens) were applied either alone or in combination with one proteolytic strain (Paenibacillus alvei) in the unprocessed lobster, crab, and shrimp SW. The method degraded the shells with high deproteinization (> 90%) and demineralization efficiency (> 90%). The degradation was confirmed through scanning electron microscopy. The highest weight loss achieved with shrimp, crab, and lobster shells was 93.67%, 82.60%, and 83.33%, respectively. B. amyloliquefaciens + P. alvei combination produced the highest weight loss in crab and lobster SW, whereas all combinations produced statistically similar weight loss in shrimp SW. There was a concurrent production of N-acetyl glucosamine (up to 532.89, 627.87, and 498.95 mg/g of shrimp, lobster, and crab shell, respectively, with P. megaterium + P. alvei and B. amyloliquefaciens + P. alvei in all SW) and amino acids (4553.8, 648.89, 957.27 μg/g of shrimp, lobster, and crab shells, respectively with B. subtilis + P. alvei in shrimp and B. amyloliquefaciens + P. alvei in crab and lobster). Therefore, it is concluded that, for the first time, efficient degradation of crustacean shell waste was observed using chitinolytic and proteolytic bacterial fermentation with the obtention of byproducts, providing a basis for further application in SW management.

Novel isatin–incorporated biopolymer Schiff base ligands extracted from lobster shell waste: synthesis, spectral characteristics, and promising metal ion up-taking property

Novel isatin–incorporated biopolymer Schiff base ligands extracted from lobster shell waste: synthesis, spectral characteristics, and promising metal ion up-taking property

Preparation of strong, water retention, and multifunctional soybean flour-based adhesive inspired by lobster shells and milk skin

The development of a water-retaining soybean flour-based adhesive with high water resistance, interfacial adhesion and mildew resistance is significant in replacing petroleum-based aldehyde-based resin. Drawing inspiration from lobster shells, soybean flour (SF), self-synthesized epoxy hyperbranched hydroxyethyl cellulose (EH) and calcium phosphate (CaP) oligomers were employed to prepare organic-inorganic hybrid composite adhesives based on hyperbranched structure. The EH component, abundant in active groups, enhanced the interfacial adhesion of the adhesives and served as an organic carrier for the mineralization of CaP oligomers. Prior to adhesive solidification, CaP oligomers mineralized to form an inorganic film akin to milk skin, which prevented water evaporation, resulting in a water retention time of 100 min for the adhesive. During adhesive curing, CaP oligomers with fluid-like behavior polymerized and mineralized, ultimately forming a continuous inorganic network of CaP crystals. This network, combined with the organic substrates (SF and EH), constituted an organic-inorganic hybrid structure, which bolstered the water and mildew resistance (20 days) of the adhesives. The prepressing intensity and wet shear strength of the resultant plywood increased by 168% and 396% to 0.67 MPa and 1.39 MPa, respectively, compared to those of the unmodified adhesive. The strength reached the leading level of the reported soybean flour adhesives. The biomimetic strategy employed here can be extended to high-performance gels and membrane materials, offering a novel modification approach for bio-composites.

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.

Pre-treatment of Lobster Shell Using Hydrochloric Acid for Nanochitosan Production

Lobster shells are a by-product that can be used as a raw material for making chitin and chitosan. However, lobster shells contain a high amount of minerals that cover the chitin polymer on the shell. This chitin can be converted into chitosan by deacetylation process. Efforts that can be made to increase the efficiency of the chitosan extraction process from lobster shells are by pre-treatment using hydrochloric acid. The purpose of this study was to determine the pre-treatment time of lobster shells with hydrochloric acid and to produce nanochitosan from lobster shells. The results of this study indicate that the pretreatment time has a significant effect on the yield value of chitosan. The highest yield of chitosan was produced from the acid pre-treatment with a soaking time of 120 hours with a value of 15,6%. The quality of lobster chitosan from the best treatment has met the quality requirements based on SNI. Nanochitosan was successfully synthesized by ionic gelation method with a particle size of 357,76 nm and spherical shape based on SEM photos. Lobster nanochitosan has the potential to be applied in various fields, such as food, agriculture,and biomedical.

High Solubility and Bioavailability of Lobster Shell-Derived Calcium for Significantly Proliferating Bone and Skin Cells In Vitro

Shell wastes pose environmental and financial burdens to the shellfish industry. Utilizing these undervalued shells for commercial chitin production could minimize their adverse impacts while maximizing economic value. Shell chitin conventionally produced through harsh chemical processes is environmentally unfriendly and infeasible for recovering compatible proteins and minerals for value-added products. However, we recently developed a microwave-intensified biorefinery that efficiently produced chitin, proteins/peptides, and minerals from lobster shells. Lobster minerals have a calcium-rich composition and biologically originated calcium is more biofunctional for use as a functional, dietary, or nutraceutical ingredient in many commercial products. This has suggested a further investigation of lobster minerals for commercial applications. In this study, the nutritional attributes, functional properties, nutraceutical effects, and cytotoxicity of lobster minerals were analyzed using in vitro simulated gastrointestinal digestion combined with growing bone (MG-63), skin (HaCaT), and macrophage (THP-1) cells. The calcium from the lobster minerals was found to be comparable to that of a commercial calcium supplement (CCS, 139 vs. 148 mg/g). In addition, beef incorporated with lobster minerals (2%, w/w) retained water better than that of casein and commercial calcium lactate (CCL, 21.1 vs. 15.1 and 13.3%), and the lobster mineral had a considerably higher oil binding capacity than its rivals (casein and CCL, 2.5 vs. 1.5 and 1.0 mL/g). Notably, the lobster mineral and its calcium were far more soluble than the CCS (98.4 vs. 18.6% for the products and 64.0 vs. 8.5% for their calcium) while the in vitro bioavailability of lobster calcium was 5.9-fold higher compared to that of the commercial product (11.95 vs. 1.99%). Furthermore, supplementing lobster minerals in media at ratios of 15%, 25%, and 35% (v/v) when growing cells did not induce any detectable changes in cell morphology and apoptosis. However, it had significant effects on cell growth and proliferation. The responses of cells after three days of culture supplemented with the lobster minerals, compared to the CCS supplementation, were significantly better with the bone cells (MG-63) and competitively quick with the skin cells (HaCaT). The cell growth reached 49.9–61.6% for the MG-63 and 42.9–53.4% for the HaCaT. Furthermore, the MG-63 and HaCaT cells proliferated considerably after seven days of incubation, reaching 100.3% for MG-63 and 115.9% for HaCaT with a lobster mineral supplementation of 15%. Macrophages (THP-1 cells) treated for 24 h with lobster minerals at concentrations of 1.24–2.89 mg/mL had no detectable changes in cell morphology while their viability was over 82.2%, far above the cytotoxicity threshold (<70%). All these results indicate that lobster minerals could be used as a source of functional or nutraceutical calcium for commercial products.