Crawfish Shell Research Articles

Recycling crawfish shell waste as co-digestion substrates to promote methane recovery and the underlying mechanisms

The efficient disposal of municipal organic wastes in low-carbon strategies is urgent but faces critical challenges. Anaerobic digestion is effective to recover high-valued resources (i.e., methane) from organic wastes; however, conventional mono-anaerobic digestion is restrained by limited organics content and imbalanced nutrient composition. This work proposed crawfish shell wastes and waste activated sludge co-digestion for effective biogas production. Results demonstrated an increase of 249.5 % methane yield in co-digestion systems compared to waste activated sludge mono-digestion. The crawfish shell wastes introduced considerable organics, which enhanced the microbial utilization of proteinaceous substrates, and prompted solubilization, hydrolysis, acidification, and methanogenesis steps. The microbial consortia were reshaped with the enrichment of hydrolytic-acidogenic bacteria (i.e., Proteiniclasticum ruminis and Acetoanaerobium sticklandii) and functional methanogens (i.e., Metanobacterium sp. and Metanopirillum sp.). Also, the methanogenic metabolic networks were stimulated, especially hydrogenotrophic methanogenesis, which was mainly attributed to the favorable conditions (including organics, pH, ORP, and trace elements) induced by crawfish shell wastes.

Chitin and crawfish shell biochar composite decreased heavy metal bioavailability and shifted rhizosphere bacterial community in an arsenic/lead co-contaminated soil

Sustainable management of ever-increasing organic biowaste and arable soil contamination by potentially toxic elements are of concern from both environmental and agricultural perspectives. To tackle the waste issue of crawfish shells and simultaneously minimize the threat of arsenic (As) and lead (Pb) to human health, a pot trial was conducted using chitin (CT), crawfish shell biochar (CSB), crawfish shell powder (CSP), and CT–CSB composite to compare their remediation efficiencies in As/Pb co-contaminated soil. Results demonstrated that addition of all amendments decreased Pb bioavailability, with the greatest effect observed for the CT–CSB treatment. Application of CSP and CSB increased the soil available As concentration, while significant decreases were observed in the CT and CT–CSB treatments. Meanwhile, CT addition was the most effective in enhancing the soil enzyme activities including acid phosphatase, α-glucosidase, N-acetyl-β-glucosaminidase, and cellobiohydrolase, whereas CSB-containing treatments suppressed the activities of most enzymes. The amendments altered the bacterial abundance and composition in soil. For instance, compared to the control, all treatments increased Chitinophagaceae abundance by 2.6–4.7%. The relative abundance of Comamonadaceae decreased by 1.6% in the CSB treatment, while 2.1% increase of Comamonadaceae was noted in the CT–CSB treatment. Redundancy and correlation analyses (at the family level) indicated that the changes in bacterial community structure were linked to bulk density, water content, and As/Pb availability of soils. Partial least squares path modeling further indicated that soil chemical property (i.e., pH, dissolved organic carbon, and cation exchange capacity) was the strongest predictor of As/Pb availability in soils following amendment application. Overall, CT–CSB could be a potentially effective amendment for simultaneously immobilizing As and Pb and restoring soil ecological functions in contaminated arable soils.

Visible-light photocatalysis degradation of enrofloxacin by crawfish shell biochar combined with g-C3N4: Effects and mechanisms

Herein, a new type of photocatalyst, that is biochar/g-C3N4 (BC/CN) composite, was successfully prepared from melamine and waste crawfish shells by a simple thermal condensation process and used to degrade enrofloxacin (ENR) wastewater under visible light. The structure and photoelectrochemical properties of the composites were thoroughly characterized. Results showed that there are obvious synergistic effects between BC and CN present in the composite. When the ratio of BC to CN is 2%, the catalyst (BC/CN-2%) has the best visible-light photocatalytic performance. The •O2− radicals were the main oxidation free radicals responsible for ENR removal and the radicals first attacked the piperazine moiety of the ENR, and further, the whole photocatalytic degradation pathway was proposed. This study provided a promising strategy for the synthesis of photocatalyst materials from waste crawfish shells and their application in the treatment of antibiotic wastewater.

Crawfish shell- and Chinese banyan branch-derived biochars reduced phytoavailability of As and Pb and altered community composition of bacteria in a contaminated arable soil

Globally, soil contamination with arsenic (As) and lead (Pb) has become a severe environmental issue. Herein, a pot experiment was conducted using pak choi (Brassica chinensis L.) to investigate the effects of biochars derived from crawfish (Procambarus clarkia) shells (CSB) and Chinese banyan (Ficus microcarpa) branches (CBB) on the phytoavailability of As and Pb, and bacterial community composition in soils. Our results showed that the application of CSB and CBB decreased the concentrations of DTPA-extractable Pb in soils ranging from 26.8 % to 28.8 %, whereas CSB increased the concentration of NH4H2PO4-extractable As in soils, compared to the control. Application of both biochars reduced the uptake of As and Pb in the edible part of pak choi. In addition, application of CBB significantly (P < 0.05) increased the activities of α-glucosidase, β-glucosidase, cellobiohydrolase, and acid phosphomonoesterase by 55.0 %, 54.4 %, 195.1 %, and 76.7 %, respectively, compared to the control. High-throughput sequencing analysis revealed that the predominant bacteria at the phyla level in both biochar-treated soils were Firmicutes, Proteobacteria, and Actinobacteriota. Redundancy and correlation analyses showed that the changes in bacterial community composition could be related to soil organic carbon content, As availability, and nutrient availability in soils. Overall, the Chinese banyan branch biochar was more suitable than the crawfish shell biochar as a potential amendment for the remediation of soils co-contaminated with As and Pb.

Effects of varying levels of crawfish (Procambarus clarkia) shell meals on growth, fillet quality, and health of koi carp (Cyprinus carpio)

The rapidly growing of the crawfish industry generates a massive quantity of waste by-products such as heads and shells. This study evaluates crawfish shell meal (CSM) as an alternative source to fishmeal. Five isonitrogenous (crude proteins, 41%, dry matter) and isocaloric (crude lipid, 6%) experimental diets, with different levels of CSM to replace fishmeal (0%, 25%, 50%, and 75%; 75% + bile acids), were formulated to feed koi carps (4.41 ± 0.1 g) for eight weeks. Fish that were fed 25% and 50% CSM diets exhibited no significant differences in growth performance or feed utilization (P > 0.05), whereas these indices decreased significantly in fish that were fed 75% CSM (P < 0.05). Additional supplementation with bile acids did not undo the adverse effects of CSM overdoses (P > 0.05). Dietary CSM increased the visceral, hepatopancreatic, intraperitoneal fat, and intestinal indices. In contrast, only 75% CSM caused the visceral, hepatopancreas, and intestinal indices to differ significantly (P < 0.05). Dietary bile acids almost restored these indices to their original values, with only the hepatopancreas index differing significantly (P < 0.05). Only 75% CSM significantly increased total serum protein, albumin, globulin, triglyceride, and very-low-density lipoprotein cholesterol levels compared to those in the control group (P < 0.05). Bile acids did not restore the original levels of these parameters (P > 0.05); however, they significantly restored the decreased muscle moisture induced by 75% fishmeal replacement (P < 0.05). No obvious differences were observed in the proximate, amino acid, and fatty acid compositions of the muscles among the various treatments (P > 0.05). The 75% CSM treatment significantly decreased muscle shearing force, which was recovered by bile acids (P < 0.05). No apparent differences in serum antioxidative and antibacterial enzymes, including catalase, total antioxidant capacity, superoxide dismutase, and lysozyme, were observed in the serum and liver; however, replacing 75% of fishmeal with CSM increased serum glutathione peroxidase and acid phosphatase activities (P < 0.05). This study demonstrates that up to 50% of fishmeal can be replaced by CSM and that additional supplementation with bile acids has trace positive effects during CSM oversupplementation (75% supplemented level).

A facile “off–on” fluorescence sensor for pentachlorophenol detection based on natural N and S co-doped carbon dots from crawfish shells

Natural N and S co-doped carbon dots (NSCDs) were synthesized via hydrothermal synthesis using food-derived crawfish shells as green precursors. The relationship between quantum yield (QY) and protein content of six crawfish shells treated with different alkalis was investigated. The synthesized NSCDs displayed a large QY of 18.57 %, which was higher than most of the chitin-derived CDs. Due to the oxidation of hydroxyl radicals, adding H2O2 and horseradish peroxidase (HRP) quenched the fluorescence of NSCDs, resulting in a detection limit (LOD) of 1.25 μM for H2O2. The addition of pentachlorophenol (PCP) was supposed to consume part of the hydroxyl radicals and protect NSCDs from being oxidized. Accordingly, a facile and rapid “off–on” fluorescence sensor was developed to detect PCP with a LOD of 2.30 μM. Further, the method described was successfully used to detect PCP in three real samples.

Reutilization of waste crawfish shell and sludge for efficient volatile fatty acids production by synchronously regulating the bioavailable substrates and microbial metabolic traits

Crawfish shell wastes (CSW) are abundant with valuable substrates, which possess great resource potentials. This work has revealed the feasibility of CSW reutilization for effective volatile fatty acids (VFAs) generation with waste active sludge (WAS) via anaerobic fermentation. The maximum VFAs generation reached 17963 mg COD/L when the CSW/WAS mass ratio was 3.25:1, while it was 784 mg COD/L in the control reactor. Meanwhile, each gram of CSW could be transformed into 264 mg COD equivalent VFAs. The feed of CSW brought in massive organic substrates, which significantly promoted the solubilization, hydrolysis and acidification processes in the CSW/WAS co-fermentation systems simultaneously. The metabolism of carbohydrates took priority over proteins in contributing to the VFAs promotion. More importantly, the functional anaerobes (i.e., Paludicola sp. and Macellibacteroides sp.), which participated in the main substrates decomposition with the VFAs as the primary metabolites, were evidently enriched in the presence of CSW. The critical hydrolases and acid-forming enzymes relevant to VFAs biosynthesis were all enhanced. Moreover, the key genes encoding for the main substrates metabolisms (i.e., chitin) and VFAs production were remarkably up-regulated. The evident promotion of microbial activities and metabolic functions was mainly ascribed to the favorable fermentation conditions (i.e., pH, ORP and C/N) induced by CSW conditioning. This study proposed an innovative strategy to recover high-value products from CSW, and in-depth insights of microbial traits and genetic functions in CSW/WAS co-fermentation systems.

PSII-14 Inclusion of popcorn and crawfish shells as components in non-feedstock silage production

Abstract As the future of agricultural sciences, it is imperative that student scientists seek to investigate alternatives to help improve production by lowering costs while meeting dietary requirements, increasing output, and maintaining sustainability. Anthropogenic waste as potential feedstock, we are engaging in an innovative wave of agricultural research. While previous research in our laboratory has evaluated newspaper, waste popcorn, and crawfish shells as feedstock, their potential for ensiling represents an alternative avenue for upcycling and long-term storage. The objective of this experiment was to determine the optimum concentrations of newspaper, waste popcorn, and crawfish shells for ideal silage fermentation. This experiment was conducted as a Box-Wilson composite design with four replications. Prescribed amounts of shredded newspaper, ground crawfish shells and heads, and waster popcorn were thoroughly mixed, and water and inoculant were added to achieve 25% dry matter. Central points for popcorn were 35.5, 1.3, 35.5, and 1.3% dry matter, respectively, for grain silage, grass silage, high combination, and low combination. Central points for crawfish were 4.0, 6.4, 4.0, and 6.4% dry matter, respectively, for grain silage, grass silage, high combination, and low combination. Samples were sealed using a food-grade sealer and allowed to ferment for 35 d. A subsample was frozen for assay of pH and silage acids. The remaining sample was dried at 55°C, ground, and assayed for NDF, ADF, CP, and IVTD. Across block, there was no effect of crawfish or popcorn inclusion on NDF (P ≥ 0.09; μ = 74%), ADF (P ≥ 0.24; μ = 60%), or IVTD (P ≥ 0.12; μ = 35%). Results are interpreted to mean that these feed ingredients may be used in non-feedstock silage production, but its usefulness to livestock production is questionable.

Effect of dietary replacement of fish meal protein with crawfish shell meal ( Procambarus clarkii ) on the growth performance, digestive enzyme activity and anti‐oxidative capacity of Oujiang color common carp ( Cyprinus carpio var. color )

This study was designed to evaluate the effects of dietary crawfish shell meal (CSM) on the growth performance, digestive enzyme activity and anti-oxidative capacity of Oujiang color common carp. 180 juvenile fish (initial weight 3.0 ± 0.5 g) were assigned to the control group and the CSM25 group (fed with 25% substitution of fish meal by CSM) for 8 weeks. Results showed that significant improvement in the weight gain rate (WGR) in CSM25 group than the control (p < .05), whereas no significant change in feed conversion ratio, specific growth rate and feeding intake between the groups (p > .05). Also, no significant difference was obsevered between the groups in terms of serum biochemical index and muscle composition (p > .05). And liver superoxide dismutase, catalase, glutathione peroxidase (GPx), lysozyme (LYZ) and protease activities in CSM25 group were significantly higher (p < .05). Moreover, histological analysis indicated that width of mucosa and thickness of muscular coat in mid-intestine were significantly changed (p < .05). In conclusion, dietary supplement with CSM25 induced high oxidative stress, promote protease activities and had no negative effects on the growth performance of Oujiang color common carp. Hence, CSM may be a viable alternative protein source to reduce the demand for fish meal.

Adsorptive removal of As(V) by crawfish shell biochar: batch and column tests.

As a toxic and metalloid substance, excess arsenic (As) can cause serious harm to the environment and public health. In this work, crayfish shell biochar (CFS450) and modified biochar (MCFS450) were prepared to remove As(V) from aqueous solutions under various conditions. Compared to CFS450, MCFS450 had a higher specific surface area, better pore structure, and higher As(V) adsorption capacity. Based on the Langmuir model, its maximum As(V) adsorption capacity was 17.2mg/g. The biochar had a large number of surface functional groups such as C-O, O-H, and -OH. After modification, a certain mass of ZnO nanoparticles existed on MCFS450, which increased positive charge on the surface and promoted the adsorption of As(V). As the temperature rose, the adsorption capacity increased, suggesting the adsorption was endothermic. Under low PH conditions, the adsorption effect was better. When Cl-, HCO3-, SO42-, and PO43- respectively existed, the adsorption capacity decreased, indicating that As(V) competed with other anions. The column adsorption experiments showed that Thomas, Yoon-Nelson, and Adams-Bohart models can be expressed as a unified model (EXY model). The EXY model can be used for the design of biochar-based filter for As(V) removal, providing a theoretical basis for practical production applications. Graphical abstract Experimental setup and results of column adsorption.

Nitrogen-doped porous carbon/Co3O4 nanocomposites as anode materials for lithium-ion batteries.

A simple and industrially scalable approach to prepare porous carbon (PC) with high surface areas as well as abundant nitrogen element as anode supporting materials for lithium-ion batteries (LIBs) was developed. Herein, the N-doped PC was prepared by carbonizing crawfish shell, which is a kind of food waste with abundant marine chitin as well as a naturally porous structure. The porous structure can be kept to form the N-doped PC in the pyrolysis process. The N-doped PC-Co3O4 nanocomposites were synthesized by loading Co3O4 on the N-doped PC as anode materials for LIBs. The resulting N-doped PC-Co3O4 nanocomposites release an initial discharge of 1223 mA h g(-1) at a current density of 100 mA g(-1) and still maintain a high reversible capacity of 1060 mA h g(-1) after 100 cycles, which is higher than that of individual N-doped PC or Co3O4. Particularly, the N-doped PC-Co3O4 nanocomposites can be prepared in a large yield with a low cost because the N-doped PC is derived from abundant natural waste resources, which makes it a promising anode material for LIBs.

STUDIES OF WHOLE CRAWFISH SHELLS FOR THE REMOVAL OF CHROMIUM, LEAD, AND SELENIUM IONS IN SOLUTION

The objective of this work was to investigate the absorption characteristics, primarily with lead but also chromium and selenium ions in solution, of whole crawfish shells. An increase in the lead concentration in spiked water showed an increase in the lead absorption level. Lead absorbed by 0.5 g of whole crawfish shells was far less when compared to absorption by 0.5 g of ground crawfish shell powder due to particle size. Some of the lead is most likely being precipitated and collected along with the powder. With increase in the volume of lead spiked water, absorption of lead by whole crawfish shells also increased. Results obtained from the pH studies indicated that basic conditions (pH 9.5) are favorable for absorption of lead by both whole crawfish shells and chitin. Crawfish shells exhibited more absorption of lead compared to commercially available (shrimp) chitin at pH 9.5. Crawfish shells absorbed more lead, selenium, and chromium from analyte spiked water when compared to chitin. However, the amount of metal added was not always equal to the amount of metal dissolved. A higher amount of lead was absorbed when compared to chromium and selenium. If comparison was done in micrograms of analyte absorbed, then the absorption order can be given as lead>chromium>selenium. If comparison was done in micromoles of analyte absorbed, then the absorption order is as follows: chromium>lead>selenium. Results from the last experiment indicated that formation of lead precipitate increased proportionately with increase in the concentration of spiked water.

Use of ground crawfish shells for the removal of chromium in solution

Crawfish shells are an abundant waste product that has the potential to remediate contaminated bodies of water. This study demonstrates that ground crawfish shell could be used as an effective biosorbent material for the treatment of chromium in contaminated aqueous solutions. Phase I experiments determined that the adsorption was completed within 2h. For the time periods examined it could be concluded that the maximum chromium adsorption occurs within the first 2h. Phase II experiments demonstrated that chromium adsorption increased with sample volume and concentration, however the efficiency decreased with increasing sample volume for the relative high concentrations of chromium. Phase III experiments showed that chitin is a major constituent for biosorption of chromium and likely other metals in crustacean species including crawfish. Salinity experiments showed that salt (sodium chloride) at the 30ppt (parts per thousand) concentrations does not affect the crawfish shell ability to adsorb chromium. The pH was the most important factor for chromium adsorption by the crawfish powder. Chromium adsorption increased with increasing pH. The presence of lead ions did not significantly interfere with the adsorption of chromium ions onto the crawfish shell powder for the relatively high concentrations examined. However, for relatively low concentrations the chromium adsorption was somewhat suppressed by the lead ions.

Investigation of Crawfish (Procambrus Clarkii) Shells for Uptake and Removal of Lead in Water

The use of ground crawfish (Procambrus clarkii) shells for the uptake and removal of Pb ions in water was investigated. Using inductively coupled plasma-optical emission spectrometry, the samples were analyzed for various concentrations of Pb at three different volumes of 40 mL, 500 mL, and 3000 mL. The results showed that with an increase in volume of water, the capacity to remove Pb by the crawfish exoskeleton shell powder decreased. However, the Pb absorption by the same amount of shell powder in all the phases was good in terms of efficiency. The phase III study (3000 mL of water) showed that 0.5 g of crawfish absorbed the maximum amount of Pb. Moreover, both raw and boiled crawfish shells have almost the same capacity to uptake Pb from water.

In vivo testing of a bone graft containing chitosan, calcium sulfate and osteoblasts in a paste form in a critical size defect model in rats

Bone loss associated with musculoskeletal trauma or metabolic diseases often require bone grafting. The supply of allograft and auto-graft bones is limited. Hence, development of synthetic bone grafting materials is an active area of research. Chitosan, extracted from chitin present in crawfish shells, was tested as a de-livery vehicle for osteoblasts in a 2-3 mm size defect model in rats. Twenty-seven male Lewis rats, divided into three groups with sacrifice intervals of 3, 6 & 9 months were used. In the experimental samples, a critical size defect was filled with chitosan bone graft paste and fixed with a plate, while in the operated control group, a critical size defect was repaired only by a plate (no paste was applied). An unoperated control group was also included. Bone growth was evaluated histologically by examining undecal-cified and decalcified stained sections. The fe-murs were also examined non-destructively by micro-computed tomography (礐T). Defects filled with chitosan bone graft paste demon-strated superior healing across all time periods compared to unfilled defects as examined by histology and micro-computed tomography. Crawfish chitosan has successfully been used as a cell delivery system for osteoblasts for use as a synthetic bone graft material.

Sorption Behavior of Crawfish Chitosan Films as Affected by Chitosan Extraction Processes and Solvent Types

ABSTRACTEffects of chitosan extraction processes and solvent types on sorption behavior of unplasticized crawfish chitosan films were investigated. Four different chitosans prepared from crawfish shell were dissolved in 1% v/v acetic, formic, lactic, or malic acids at 1% w/v concentration. Chitosans dissolved in acetic or formic acid formed flexible and transparent films that are desirable for packaging applications. Chitosan acetate films maintained lower moisture contents at any relative humidity level compared with chitosan formate films. The type of chitosan significantly influenced the sorption isotherms of chitosan formate films but not chitosan acetate films. The Guggenheim‐Anderson‐de Boer, Oswin, and Caurie models (R2= 0.98, 0.95, and 0.95, respectively) could be used to predict sorption behavior of crawfish chitosan acetate and formate films.

Astaxanthin Extraction from Crawfish Shells by Supercritical CO2 with Ethanol as Cosolvent

Astaxanthin is an important pigment in fish and shellfish aquaculture and increases the market value of fish such as salmon and trout. Commercially synthesized astaxanthin costs about $1,000/kg. Carotenoids have been extracted from crustacean wastes with organic solvents, but in many of the methods the pigments are degraded. Astaxanthin extraction yield from crawfish tail shells by supercritical CO2 was optimized for temperature, pressure, and moisture. The cosolvent ethanol (10% w) increased yield significantly. Temperature, pressure, and moisture content were other important independent variables. These were studied using an incomplete 33factorial (Box-Behnken) design. The equation of the model fitted to the data was extracted astaxanthin (mg/kg dry shell) = -169.3 + 5.36 T + 0.061 P + 7.32 M -0.0003 T P -0.10 T M + 0.0003 M P -0.02 T2 -0.000006 P2 -0.033M2, where T = temperature; P = pressure (psi); M = moisture. The maxima for moisture, pressure, and temperature were 13, 24 MPa, and 75, respectively.

Predicting Crawfish Molting with Machine Vision

AbstractThe objective of this project was to develop a vision system that could predict when crawfish will molt. Different sections of the crawfish shell were examined to determine how the color changed as the time of molting approached. A strip on the tail section of the crawfish showed the greatest, most consistent color change. The average red/green × red/blue ratio decreased for every crawfish as the molting time approached. Using this ratio as a predictor, it was possible to predict the molting of a crawfish within 3 d with an accuracy greater than 80%. The limitation on accuracy was primarily the result of the large variations in natural shell color among the crawfish.

Isolation and characterization of chitin from crawfish shell waste

Comparaison des rendements et de la composition en chitine, proteines, calcium et pigments (astaxanthine) des carapaces de crustaces et des farines derivees. Les methodes de dosage sont decrites pour chaque fraction. Utilisations possibles en alimentation animale

Recovery of Amino Acids from Seafood Processing Wastewater with a Dual Chitosan‐Based Ligand‐Exchange System

ABSTRACTCrawfish chitosan, prepared from crawfish shell chitin, was demonstrated to be an effective ligand‐exchange column material for recovery of amino acids from seafood processing wastewater. In comparison with commercial chitosan, crawfish chitosan, loaded with copper or amino copper, showed higher recovery rates of amino acids. Recovery from amino copper‐crawfish chitosan columns was pH dependent, with reduction at higher pH values. Eluatc was completely free of copper ions when treated with a second crawfish chitosan column. The amino acids recovered by this treatment have potential application as seafood flavors in terms of their sensory attributes.