Canine Extremity Wound Treatment with Chitosan Extracted from Shrimp Shells： A Case Report

The aim of this case report was to demonstrate the effectivity of chitosan as topical agent on the treatment of severely infected canine extremity wound. The dog was hit by a bus and presented severe friction wounds accompanying with bilateral hip and extremity fractures. Local and generalized infections were observed on the post operational period. The dog was unresponsive to the standard therapeutic protocols and health status was getting worsened. The regenerative sutures did not hold the tissues because of the infection and the tissue eruption. Chitosan samples were extracted from shrimp shell wastes. The milled form of chitosan was topically used to treat the open and heavily mix infected wound areas located at skin and rear extremities accompanying with fever and Canine coronavirus diarrhea. It was decided to use the chitosan as a bio barrier and anti-bio affect over the damaged and erupted tissues. Macroscopic fmdings indicated chitosan promoted the natural blood clotting and absorbed the inflammation fluid. Microscopic findings indicated the infiltration of polymorph nuclear leukocytes （PMN） accelerated with the topical use of chitosan in the early phase of wound healing. The wound healing was observed daily. This veterinary practice wound treatment result indicated that chitosan is effective to medicate topically the canine open and mix infected wounds with bacteria and viruses and promotes the granulomatosis in four weeks period.

Extraction and Characterization of Chitosan from Shrimp Shells

Chitosan is one of the most studied polysaccharides nowadays. Because it is non-toxic, widely used in food, pharmaceutical processes, agricultural, and presents excellent biological properties such as biodegradation in the human body, and antibacterial. In the present study we reported the extraction of low cost chitosans (Cs1, Cs2, Cs3 and Cs4) from shrimp shells by extraction of chitin (Egypt: case study), then alkaline deacetylation of chitin with strong alkaline solution at different period of time. The different prepared chitosans (Cs1, Cs2, Cs3 and Cs4) were characterized by FTIR spectroscopy, thermal stability, morphology, crystallography, elemental analysis and degree of deacetylation. The data showed that the prepared chitosan Cs2 has the most thermal stability and the highest degree of deacetylation.

Single Cu atom dispersed on S,N-codoped nanocarbon derived from shrimp shells for highly-efficient oxygen reduction reaction

Recently,Cu-based single-atom catalysts(SACs)have garnered increasing attention as substitutes for platinum-based catalysts in the oxygen reduction reaction(ORR).Therefore,a facile,economical,and efficient synthetic methodology for the preparation of a high-performance Cu-based SAC electrocatalyst for the ORR is extremely desired,but is also significantly challenging.In this study,we propose a ball-milling method to synthesize isolated metal SACs embedded in S,N-codoped nanocarbon(MNSDC,M=Cu,Fe,Co,Ni,Mn,Pt,and Pd).In particular,the Cu-NSDC SACs exhibit high electrochemical activity for the ORR with half-wave potential(E_(1/2))of 0.84 V(vs.reversible hydrogen electrode(RHE),20 mV higher than Pt/C)in alkaline electrolyte,excellent stability,and electrocatalytic selectivity.Density functional theory(DFT)calculations demonstrated that the desorption of OH*intermediates was the rate-determining step over Cu-NSDC.This study creates a pathway for high-performance ORR single atomic electrocatalysts for fuel cell applications and provides opportunities to convert biowaste materials into commercial opportunities.

广东罗定龙塘碱性花岗岩锆石SHRIMP定年及地质意义

龙塘碱性花岗岩位于广东云开大山地区,属罗定泗纶混合岩田区,其中的锆石均为具有老核新壳的变质复合型锆石。SHRIMP定年结果,新壳6个测点加权平均年龄为265±1·8Ma,反映该岩体的成岩年龄,相当于中二叠世,属于海西晚期。老核获得最大的U-Pb年龄为1098Ma,相当于中元古代;457Ma和414Ma可能是新壳和老核的混合年龄。根据锆石的成因类型,结合微观所见的岩石结构(反映沉积变质成因的粒状变晶结构和花岗变晶结构等),表明该碱性花岗岩的成因可能是砂泥质沉积物经变质而成。

Extraction and Characterization of Litopenaeus vannamei’s Shell as Potential Sources of Chitosan Biopolymers

Chitin is the second most abundant polysaccharide,produced mainly as an industrial waste stream during crustacean processing.Chitin can be derived into chitosan through the deacetylation process.Conversion of shrimp waste into chitosan via the deacetylation process could be considered a practical approach for shell waste remediation.In this study,chitosan’s physicochemical characteristics extracted from two types of Pacific white leg shrimp,L.vannamei’s shell(i.e.,rough and smooth),were compared with commercial chitosan.The yield,moisture,ash,solubility,water and fat binding capacity were measured.The degree of deacetylation(DDA)was calculated using FTIR,and their chemical Structure was confirmed using XRD and SEM-EDS.Both extracted chitosan showed no significant difference in yield,moisture,ash,solubility and water binding capacity but showed a significant difference with commercial chitosan.Moreover,the fat binding capacity of commercial chitosan showed the lowest percentage(408.34±0.83%)as compared to extracted chitosan(smooth shell 549.59±12.48%;rough shell 500.55±12.10%).The DDA indicated that extracted chitosan from the smooth and rough shell was considered good chitosan as compared to commercial chitosan with 84.08±1.27%,80.78±0.79%and 74.99±1.48%,respectively.Additionally,the presence of hydroxyl and amino groups from FTIR and a good crystallinity index was recorded using XRD of extracted chitosan.Based on observed characteristics,shrimp shell waste from L.vannamei can achieve chitosan standard quality as a biopolymer and highly potential to be applied in various industrial applications.

Production of Glucosamine Hydrochloride from Crustacean Shell

The use of chitin as raw material to obtain glucosamine hydrochloride at laboratory level was investigated. Chitin was extracted from shrimp shells by deproteinization, demineralization and depigmentation. Afterwards, glucosamine hydrochloride was produced in four main stages： （1） acid hydrolysis of chitin with 12 M hydrochloric acid using the reflux technique; （2） filtration of the solution to discard solid impurities; （3） recrystallization of the product using 95% ethyl alcohol as solvent, and （4） filtration, washing and drying of final product at 50 ℃. The FTIR spectrum of the product was compared to a commercial glucosamine hydrochloride of 99.86% purity, and a coincidence between 96.90% and 99.66% was obtained. The influence of temperature, solid/liquid ratio （g/mL）, and agitation （with-without） on acid hydrolysis was studied. The best correlation corresponds to the hydrolysis product obtained at solid/liquid ratio of 1：20, temperature of 85 ℃, and with agitation. The yields of glucosamine hydrochloride with respect to chitin were 42, 58, 36 and 48% for solid/liquid ratios of 1：10, 1：20, 1：30, and 1：40 respectively, at high hydrolysis reaction temperature and with agitation. These results showed that in the range examined, glucosamine hydrochloride with high quality is produced with solid/liquid ratio of 1：20.

超声波和碱性蛋白酶处理对克氏原螯虾脱壳及虾仁品质的影响

为研究超声波和碱性蛋白酶处理对克氏原螯虾脱壳及虾仁品质的影响,通过壳分离功、虾仁得率、虾仁质构、色泽、气味、嫩度、离心损失、肌原纤维蛋白含量等指标进行分析,确定克氏原螯虾脱壳的最佳前处理方式。结果表明:相对于传统加工方式,0.5%碱性蛋白酶和300 W超声波联合处理,能有效降低壳分离功21.8%,提高虾仁得率31%,并且显著提高了虾仁的嫩度和肌原纤维蛋白含量,硬度有所下降,气味和色泽方面无显著变化,研究结果为克氏原螯虾加工工艺的优化提供参考。

地衣芽孢杆菌对几丁质的降解作用及其发酵工艺优化

本试验筛选到一株高效产几丁质酶的地衣芽孢杆菌(Bacillus licheniformis bl3)菌株,为了提高该菌产几丁质酶的能力,提高降解虾壳的效率,对bl3菌株的发酵条件和培养基组分配比进行了优化。结果表明,bl3产几丁质酶的最适条件为pH 4.5~5.5,温度37~45℃,转速120 r·min^(-1),接种量0.40%,酶活性最高时间为36 h。通过Plackett-Burman设计试验、最陡爬坡试验和响应面试验,得到bl3产几丁质酶的最优培养基配方为虾壳11.406 g·L^(-1),KH_(2)PO_(4)0.601 g·L^(-1),MgSO_(4)·7H_(2)O0.263 g·L^(-1),酵母粉3.500 g·L^(-1),FeSO_(4)·2H_(2)O 15.00 mg·L^(-1),ZnSO_(4)0.750 mg·L^(-1)。优化后bl3发酵产几丁质酶活性达98.122 U·mL^(-1),相较于初始培养条件提高2.43倍。优化组合培养基中的虾壳、KH_(2)PO_(4)和MgSO_(4)·7H_(2)O含量以及维持稳定pH,可促进地衣芽孢杆菌持续生长和高效合成几丁质酶量。研究结果可为bl3菌株在降解几丁质方面的应用提供科学依据。

“虾壳生物质炭活化过硫酸盐降解2,4-二氯酚”创新实验设计

将科研成果与创新创业实践教学相结合,设计实施创新综合探究实验,以虾壳为原料制备虾壳生物质炭,用于活化过硫酸盐降解2,4-二氯酚。实验结果表明,虾壳生物质炭在酸性和中性条件下可以有效活化过硫酸盐去除2,4-二氯酚,去除率可达96%。通过该实验,学生能够掌握纳米材料的制备、表征等基本实验技能,能够对数据进行处理和分析,树立“以废治废”理念,增强解决实际问题的能力,提高创新意识。

虾壳源多肽酶解条件的优化及其抗冻活性和作用机制的探究

目的优化从虾壳中提取多肽的酶解条件,并探究虾壳多肽的抗冻活性及作用机制。方法以小龙虾虾壳为原料,使用复合酶酶解提取多肽。在单因素实验的基础上,通过正交实验得到虾壳最佳酶解条件。以面包酵母菌为抗冻测试对象测试其抗冻能力。采用液相色谱-串联质谱法(liquid chromatography-mass spectrometry,LC-MS/MS)对虾壳多肽的组成进行鉴定,基于多肽的理化性质和序列,结合抗冻预测平台筛选抗冻肽(antifreeze peptides,AFPs)。使用分子动力学模拟探究了AFPs的作用机制。结果在酶解温度40℃,底物质量浓度20mg/mL,加酶量12000U,酶比0.33的最佳酶解条件下,多肽提取率达到了70%以上。虾壳多肽中含有1004种肽段,能明显提升酵母菌存活率。从具有抗冻活性且置信度靠前的20条多肽中进一步筛选出了潜在的抗冻肽AFP1、AFP2。AFP2和冰面之间形成的氢键数量为14,部分水分子同时与2个氨基酸残基形成氢键,充当水桥稳定多肽的构象,AFP2与冰之间的结合能为-105.08 kcal/mol,冰结合模拟效果理想。结论AFPs与冰结合并抑制冰晶生长可能归因于带电荷的亲水性氨基酸残基与水分子形成的氢键、范德华力等分子间作用力,可开发为有益的冷冻保护剂,用于冷冻食品加工,具备良好的应用前景。

镧改性虾壳低温热解制备的生物炭对池塘养殖废水磷吸附的研究

为提高生物炭对磷的去除效果和将厨余废弃物的资源化利用,文章以废弃虾壳为原料,用NaOH将LaCl_(3)以La(OH)_(3)沉淀形式附着在虾壳表面,进行热解得镧改性生物炭(CSLa)。采用XRF、SEM、BET、FTIR和XRD对改性前后的生物炭表征分析。采用吸附等温线模型和吸附动力学模型拟合生物炭的吸磷特征。研究了改性剂用量、初始pH、共存干扰离子对生物炭吸附磷的影响。结果表明镧化合物负载在生物炭表面,对磷吸附能力明显提高,最大理论吸附量为160.51 mg/g,与CS400磷最大吸附量(100.60 mg/g)相比约提高60%。在低浓度或高浓度磷溶液条件下,CSLa对磷吸附量和去除率均高于CS400,在实际水产养殖废水中更实用。吸附过程主要受化学吸附、颗粒内扩散控制。有关机理分析的结论表明表面沉淀作用、静电吸引、配体交换和内层络合作用是CSLa吸附磷的主要机理。CSLa更适合在弱酸性环境中除磷,不过在碱性环境条件下其吸附量也比较高。HCO_(3)^(-)和CO_(3)^(2-)对CSLa磷吸附有一定的抑制作用。研究以低温400℃为热解温度制备镧改性生物炭,不仅提升了生物炭对磷的吸附量和去除率,而且消耗热能较少,更有利于实际应用。

天然调味虾粉的研制及其贮藏品质分析

我国是水产品进出口大国,对虾因肉质鲜美、营养丰富,居于水产品食用之首。近年来,随着人们对对虾食用的需求日益增大,虾加工副产品的产量也逐年递增,目前对虾副产品已用于虾酱、虾油、虾壳粉的制备。虾壳粉因其独特的鲜香味可用作日常调味品,在提供营养的同时带给人们味蕾的享受,但虾壳粉品质会随着贮藏时间的延长而逐渐下降,产生氧化反应、内源酶活性丧失等问题。该研究以对虾虾壳为原料制备虾壳粉,研究虾壳粉在常温贮藏过程中氨基酸含量、蛋白质含量、脂肪含量、虾青素含量、过氧化值(POV)、酸价(AV)、硫代巴比妥酸(TBA)值的变化规律。结果表明,在常温贮藏75 d后,蛋白质含量、脂肪含量、虾青素含量分别由0.78%、4.7%、295.75μg/g逐渐降低至0.25%、3.9%、80.6μg/g。同时,POV、AV出现明显升高趋势,TBA值先上升后下降。因此,在虾壳粉常温贮藏过程中发生了脂质氧化和营养成分流失的问题。该研究结果对延缓和控制虾壳粉贮藏过程中品质的变化提供了理论依据。

响应面法优化猴头菇虾仁辣椒酱工艺研究

为丰富辣椒酱的口味,提高猴头菇资源的综合利用率,在现有辣椒酱的基础上添加猴头菇和虾仁,开发一款具有猴头菇风味的新型辣椒酱。该研究通过单因素试验和响应面试验设计构建多元回归模型,优化猴头菇虾仁辣椒酱生产工艺,测定其亚硝酸盐含量、pH值、色泽等指标,并对最优产品的营养物质及理化、卫生指标进行分析。结果表明,猴头菇虾仁辣椒酱的最佳工艺配方为猴头菇干添加量101.55 g、大红辣椒添加量364.85 g、植物油添加量450 g、虾仁添加量65.90 g、豆瓣酱添加量8.45 g、香辛料添加量12 g、盐添加量3 g。按此配方生产的猴头菇虾仁辣椒酱的感官评分达到(90.86±2.05)分,且产品颜色红润有光泽,风味协调,酱体浓稠适中。经测定,产品的蛋白质含量为8.0 g/100 g,氨基酸态氮含量为0.17 g/100 g,膳食纤维含量为8.68 g/100 g,钠含量为538 mg/100 g,钙含量为55 mg/100 g,且微生物指标测定结果均符合国家标准要求。该研究结果为食用菌调味品的精深加工提供了理论依据,也为实现猴头菇产品的开发和综合利用奠定了基础。

高效虾壳脱蛋白菌株的筛选、产酶条件优化及酶学性质研究

该研究旨在筛选高效虾壳脱蛋白菌株并进行工艺优化及酶学性质研究。先通过单因素、Placket-Burman(PB)和正交优化试验对筛选菌株虾壳脱蛋白工艺优化,进一步对酶学性质和降解产物进行研究。结果表明,菌株铜绿假单胞菌(Pseudomonas aeruginosa)Gxun-7脱蛋白效果最好;最优产酶条件为:虾壳粉40 g/L,玉米浆5 g/L,接种量1%(体积分数),初始pH 7.0,发酵温度35℃,发酵时间48 h,优化后酶活性达(617.13±22.11)U/mL,较优化前提高了43.50%,此时,虾壳脱蛋白率为(82.61±0.54)%;菌株Gxun-7所产蛋白酶为诱导酶,酶的耐盐性较好,最适温度和pH值分别为60℃和7.0,除Cu^(2+)和Al^(3+)对酶活性有显著抑制外,其他金属离子对酶活影响不大,十二烷基磺酸钠(sodium dodecyl sulfate,SDS)和十六烷基三甲基溴化铵(hexadecyl trimethyl ammonium bromide,CTAB)抑制酶活性超过40%,而β-巯基乙醇却能提高酶活性到468%;降解液中共检测出17种氨基酸,含量达1856.14 mg/L。因此,Gxun-7对虾壳具有高效脱蛋白能力,所产蛋白酶稳定性强,降解液中氨基酸含量丰富,为虾壳蛋白降解及利用提供理论依据。

不同接种量下不同浓度虾壳粉对红曲霉发酵产红曲色素对比研究

目的:小龙虾虾壳废弃物排放造成环境污染和资源浪费,红曲霉可以转化利用虾壳蛋白质,达到对红曲色素生产的工艺优化。方法:以小龙虾虾壳废弃物蛋白质为唯一氮源,利用红曲霉菌种MonascusGN01进行液态发酵,探究不同接种量对红曲霉液态发酵产红曲色素和桔霉素的影响,得到低桔霉素高红曲色素生产工艺。结果:在5%接种量下,虾壳粉添加量为0.5%的发酵液红曲红色素的色价最高,为10U/mL,其桔霉素含量为0.004mg/L;在10%接种量下,虾壳粉添加量在1.1%时的发酵液红曲红色素色价最高,为49.75 U/mL,其桔霉素含量为0.032mg/L。结论:在实际生产中应根据不同的目的选用合适的接种量,为红曲霉发酵虾壳确定初步的工艺参数。

虾蟹壳废弃物中几丁质的制备及应用进展

随着虾蟹生产和消费量的逐渐增加,大量虾蟹壳直接当做垃圾处理,造成很大的环境压力。虾蟹壳中含有丰富的几丁质,如能对其进行提取制备,既有助于减轻环境污染又能提高资源利用率。受现有制备技术、生产成本和节能环保的影响,目前利用废弃虾蟹壳制备几丁质仍处于中小型规模。科研人员一直致力于开发新的制备方法及优化工艺,希望能够扩大虾蟹壳几丁质的生产规模,提高废弃资源利用效率。本文主要阐述了利用化学法、生物法、物理法从虾蟹壳废弃物中制备几丁质的研究现状,分析各种制备方法的优缺点、存在的问题和发展前景,以及几丁质在抑菌剂、吸附剂、生物膜等方面的应用情况。目前工业上主要采用传统酸碱法制备几丁质,其优势在于技术成熟,工艺流程简单,操作方便,但该方法使用强酸强碱,存在对环境二次污染的问题。与之相比,低共熔溶法、酶解法及微生物发酵法更具环境效益,因此开发低成本天然低共熔溶剂、构建重组酶、构建功能菌群,是未来虾蟹壳废弃物中制备几丁质的研究重点。

南美白对虾虾头、虾壳化学成分的对比研究

对比研究了南美白对虾虾头、虾壳的一般化学成分及氨基酸、脂肪酸、矿质元素组成。结果表明,虾头、虾壳水分含量最高,分别为78.44%和75.15%;蛋白质、灰分、甲壳素含量丰富,以湿重计,虾头中分别为6.38%、3.62%和3.33%,虾壳中分别为5.22%、5.30%和6.67%;虾头中脂肪、总糖及总酸度以湿基计分别为2.42%、0.27%和2.30%,虾壳中则依次为1.09%、0.16%和2.29%。虾头、虾壳中氨基酸种类齐全,矿质元素含量丰富,含有人体8种必需氨基酸、4种呈味氨基酸以及7种对人体有益的微量元素。虾头、虾壳中油酸、亚油酸、DHA和EPA含量丰富,不饱和脂肪酸含量分别占游离脂肪酸总量的55.57%和48.42%(以干基计)。对比而言,虾头中脂肪、总糖、蛋白质高于虾壳,分别为虾壳的2.22倍、1.69倍和1.22倍;虾头中氨基酸总量及游离脂肪酸总量也明显高于虾壳,分别为虾壳的1.37倍和2.96倍;但虾壳中甲壳素含量显著高于虾头,为虾头的2.00倍;此外,虾壳中钙元素含量极高,占原料干重的19.6%,比虾头高1.87倍。

壳聚糖的改性及在印染废水处理中的应用

以海洋渔业废弃物虾壳为原料,采取去矿化、脱蛋白、脱色、碱洗的方式制备壳聚糖,通过聚合氯化铝、聚合氯化铁和五水硫酸铜对壳聚糖进行改性,得到3种改性壳聚糖:聚铝-壳聚糖、聚铁-壳聚及硫酸铜-壳聚糖,并通过扫描电子显微镜和红外光谱表征改性壳聚糖的形貌及化学组成。以模拟印染废水为研究对象,在适宜条件下对改性壳聚糖加以应用,以废水的COD去除率和脱色率为考察指标,评价壳聚糖的改性效果,为改性壳聚糖处理印染废水提供理论支持。由扫描电子显微镜结果可知,聚铝-壳聚糖的表面颗粒为类球形,粒径尺寸均一且壳聚糖分布均匀,聚铁-壳聚糖和硫酸铜-壳聚糖的表面颗粒为块状,而壳聚糖主要是以带状的形式存在;由红外光谱可知,通过聚铝和聚铁对壳聚糖进行改性,引入更多的O-H和N-H振动峰,有利于印染废水的吸附沉降。研究表明:3种类型的改性壳聚糖中,聚铝-壳聚糖处理印染废水的效果最好,废水的COD去除率和脱色率最高;对聚铝-壳聚糖处理印染废水的p H、改性壳聚糖质量配比及投加量进行优化,可知,聚铝-壳聚糖对印染废水的处理效果受p H值的影响较小,在聚铝与壳聚糖质量配比为3∶1及投加量为1.6 g·L-1的条件下,p H为5.5时,模拟印染废水的COD去除率和脱色率分别达到90.5%和97.3%,p H升高至9.5时,模拟印染废水的COD去除率和脱色率仍能高达85.1%和94.2%。在最佳条件下,采用聚铝-壳聚糖处理实际印染废水,其COD去除率及脱色率分别为88.7%及96.9%。

高效液相色谱法测定虾壳中的虾青素

建立高效液相色谱法(HPLC)测定虾壳中虾青素的方法。通过正交试验考察虾壳中虾青素的最佳提取条件。结果表明,以乙酸乙酯为提取剂,超声波辅助处理30min,后振荡15min,重复两次,虾青素可被充分提取。该方法虾青素质量浓度在0.2～10μg/mL内具有良好的线性关系(R2=0.9999),回收率在80.41%～109.21%之间,相对标准偏差在4.65%～7.45%之间,虾青素定量限为0.075mg/kg。该法分析快速准确、灵敏度高、重现性好,回收率高。

生物技术清洁生产替代高污染化学法制备甲壳素的研究与应用

从虾壳中分离到一株乳杆菌BR-3,研究发现其最佳发酵起始pH为6.50,最佳培养温度为35℃,在此培养温度下达到对数生长期的时间为42h。采用乳杆菌发酵方法,进行了虾壳制备甲壳素的研究,比较了接种量、葡萄糖加入量、发酵时间等因素对产品质量的影响。结果表明,当接种量为10%、葡萄糖浓度为4.5%、固液比为1︰3、发酵温度为(35±2)℃、发酵时间为3—4d时,平均灰分去除率达95.67%,甲壳素产品灰分含量均小于6%,最低可达1%,产品质量等于或优于传统的酸碱生产方法。发酵液可部分或全部回收,洗涤废水可作下一轮发酵用水,生产废水接近零排放。虾壳乳酸发酵法生产甲壳素是一种清洁生产方法。BR-3培养时间短,培养条件粗放,温度和pH适应范围宽,产酸效率高,残糖少,适合于工业化生产。