利用黑曲霉菌丝体制备壳聚糖的研究

本试验以试验室发酵的黑曲霉菌丝体为原料,采用酸碱交替法从中提取甲壳素,然后将甲壳素脱乙酰转化为壳聚糖。运用碱煮法由甲壳素脱乙酰基制备壳聚糖时,在反应前采用盐酸对甲壳素进行预处理,并通过单因素试验和正交试验分析了反应时间、碱液浓度、温度等对壳聚糖脱乙酰度和产率的影响,得出了制备高脱乙酰度壳聚糖的最优条件为：NaOH浓度40%,反应温度110℃,反应时间6h。     

蝇蛆壳制备壳聚糖的工艺条件研究

本试验探索了蝇蛆壳制备壳聚糖的最佳工艺条件。以蝇蛆壳中甲壳素为原料,采用碱液法制备壳聚糖。通过单因素试验考察了碱液浓度、液料比、反应时间对壳聚糖脱乙酰度的影响;根据Box-Benhnken中心组合试验设计原理,采用三因素三水平响应面分析法优化脱乙酰基反应条件,依据回归分析确定工艺条件的主要影响因素,以壳聚糖脱乙酰度为响应值作响应面和等值线图。通过分析各个因素的显著性和交互作用,得出脱乙酰基反应的最佳工艺条件为:液料比57.49:1(V/m),碱液浓度50%,反应时间7.3 h。在此条件下所得壳聚糖的脱乙酰度理论值为83.18%,实测值为79.45%,并得到白色粉末状壳聚糖。     

蚕蛹壳聚糖制备条件研究

对蚕蛹甲壳素脱乙酰制备壳聚糖的条件进行了研究。通过单因素实验考察了NaOH浓度、处理温度、时间以及甲壳素与NaOH溶液的配比对脱乙酰的影响,在此基础上经正交实验优化蚕蛹壳聚糖制备条件。结果表明,NaOH浓度对蚕蛹甲壳素脱乙酰的影响最大,其次为处理温度,处理时间和固液比影响较小,优化后的处理条件为:NaOH浓度50%、处理温度90℃、时间10h、固液比1:15。经验证实验,在该条件下,制得的蚕蛹壳聚糖脱乙酰度可达到74%。     

梭子蟹壳酶解余料制取甲壳素和壳聚糖的工艺研究

研究采用酸碱法从梭子蟹壳再利用后的余料中制取甲壳素和壳聚糖的工艺条件。提取甲壳素工艺中,通过单因素试验确定脱钙最优工艺参数为:温度30℃、盐酸浓度6%、酸浸时间4h;脱蛋白最优工艺参数为:温度90℃、NaOH浓度6%、碱煮时间2h。通过正交试验确定制取壳聚糖最优工艺条件为:温度90℃、NaOH浓度50%、时间9h。制取的甲壳素和壳聚糖质量指标均达到食品级标准。     

葡萄糖酸钠发酵废弃菌丝体提取壳聚糖的研究

以产葡萄糖酸钠的废弃菌丝体为原料,探究了从废弃黑曲霉（Aspergillus niger）菌丝体提取壳聚糖的工艺条件。对废弃菌丝体进行了各组分分析后,在单因素的基础上对提取工艺进行优化,得出了碱法提取壳聚糖的最佳优化条件：料液比为1∶30（g∶mL）,6% NaOH处理2 h,反应温度为95 ℃时,菌体蛋白去除率达到77.26%;碱（NaOH）浓度为30%,处理温度为120 ℃,脱蛋白处理后样品采用重复碱处理的方式脱乙酰,样品分两次重复用30% NaOH溶液在120 ℃下各处理1 h,得到壳聚糖的脱乙酰度为78.85%,壳聚糖得率为10.53%;后续用12%醋酸纯化处理,得到脱乙酰度为84.49%的壳聚糖,得率为9.56%。     

柠檬酸废渣制取壳聚糖中微波辅助脱蛋白工艺研究

以生产柠檬酸的发酵废渣为原料制取壳聚糖为目标,首次对微波技术辅助稀碱法脱除柠檬酸废渣中蛋白的工艺进行了研究.采用单因素实验分别探讨了四个因素对废渣脱氮的影响,并用正交实验进行了工艺条件优化,所得的甲壳素采用微波浓碱法脱乙酰制取壳聚糖.结果表明,当NaOH浓度2.5%(w/w)、NaOH与湿渣用量比22:1(碱液量mL:废渣g)、微波时间9min、微波功率250W时,甲壳素含氮5.85%,得到的壳聚糖脱乙酰度为80.1%、黏度为396mPa·s.该法大大减少目前加热稀碱法脱除柠檬酸废渣中蛋白的时间,降低了能耗.     

甲壳素微波法脱乙酰制备壳聚糖的研究

本文采用微波技术由甲壳素脱乙酰制备壳聚糖，首次对在微波反应前采用乙醇浸泡对甲壳素进行预处理的条件进行了较为系统的研究，并通过单因素试验和正交试验分析了微波反应时间、碱液浓度、乙醇浸泡时间、乙醇浓度、微波功率对壳聚糖脱乙酰度和粘均分了量的影响，提出了制备高脱乙酰度、高粘均分予量壳聚糖的最优条件为（微波功率462W）：微波反应时间20min，NaOH浓度50％，乙醇浸泡时间2、5h，乙醇浓度80％。在该条件下制得的壳聚糖脱乙酰度为77.07％，粘均分子量为43．13万，得率为68．98％。     

高脱乙酰度蛹渣壳聚糖制备工艺优化

制备高脱乙酰度蛹渣壳聚糖。在蛹渣壳聚糖制备工艺单因素试验研究的基础上,应用二次回归正交旋转组合设计方法研究无水乙醇浸泡时间、氢氧化钠溶液质量分数、处理温度、处理时间及料液比对壳聚糖脱乙酰度的影响,建立脱乙酰度对5 个试验因素的正交回归模型,通过频率分析法确定蛹渣壳聚糖较优的制备条件范围并得到蛹渣壳聚糖的最佳制备工艺。最佳工艺为：无水乙醇浸泡1.7h、氢氧化钠溶液质量分数44%、处理温度94℃、处理时间9h、料液比1:28(g/mL)、每2h 换碱1 次。在此工艺条件下,壳聚糖的脱乙酰度95.96%、相对分子质量7.45 × 105、产率56.98%、水分含量3.20%、灰分含量0.35%,产品为原白色,外观色泽好,主要指标均达到相关企业标准。     

红曲废菌渣中有效成分的综合提取工艺

为提高废弃红曲霉菌丝体有效成分的利用率,在单因素实验的基础上,通过正交实验对红曲色素和粗蛋白的提取条件、麦角固醇的皂化条件及壳聚糖的脱乙酰条件进行了优化。结果表明:红曲色素提取条件为乙醇体积分数为80%,温度为50 ℃,时间为30 min,料液比为1:34 (g:mL);粗蛋白提取条件为pH为9,温度为45 ℃,时间为2 h;麦角固醇皂化条件为NaOH溶液浓度为14%,温度为90 ℃、时间为2 h、料液比为1:8 (g:mL);壳聚糖碱法脱乙酰条件为碱液浓度为45%,温度为110 ℃,时间为3 h。采用该工艺,最终红曲废渣中红曲色素、粗蛋白、麦角固醇和壳聚糖的得率分别达到94.41%、65.23%、4.16%、3.64%。通过该途径可一次性综合提取红曲色素、粗蛋白、麦角固醇和壳聚糖,达到资源利用的最大化。     

蛹渣甲壳素的提取和壳聚糖的制备研究

以提取蛹油和蛹蛋白后的蛹渣为原料,提取蛹渣甲壳素,研究制备蛹渣壳聚糖的最佳工艺条件,并对产品质量进行分析.结果表明,间歇碱处理制备壳聚糖方法的脱乙酰度高于连续碱处理方法,制取蛹渣壳聚糖的最佳工艺条件为:NaOH溶液浓度为50%,处理温度为95℃,处理时间为14h,甲壳素与NaOH溶液配比(m:v)为1:25,每2h换碱一次,产品水洗至中性,反复进行7次,可得到脱乙酰度为80.61%,黏度为245mPa·s,水分含量为7.68%,灰分含量为0.40%的白色粉末状壳聚糖,产率为56.38%.产品质量指标符合相关企业标准,本法具有较强的操作性和可行性.     

Production,properties, and some new applications of chitin and its derivatives

Chitin is a polysaccharide composed from N-acetyl-D-glucosamine units. It is the second most abundant biopolymer on Earth and found mainly in invertebrates, insects, marine diatoms, algae, fungi, and yeasts. Recent investigations confirm the suitability of chitin and its derivatives in chemistry, biotechnology, medicine, veterinary, dentistry, agriculture, food processing, environmental protection, and textile production. The development of technologies based on the utilization of chitin derivatives is caused by their polyelectrolite properties, the presence of reactive functional groups, gel-forming ability, high adsorption capacity, biodegradability and bacteriostatic, and fungistatic and antitumour influence. Resources of chitin for industrial processing are crustacean shells and fungal mycelia. Fungi contain also chitosan, the product of N-deacetylation of chitin. Traditionally, chitin is isolated from crustacean shells by demineralization with diluted acid and deproteinization in a hot base solution. Furthermore, chitin is converted to chitosan by deacetylation in concentrated NaOH solution. It causes changes in molecular weight and a degree of deacetylation of the product and degradation of nutritionally valuable proteins. Thus, enzymatic procedures for deproteinization of the shells or mold mycelia and for chitin deacetylation were investigated. These studies show that chitin is resistant to enzymatic deacetylation. However, chitin deacetylated partially by chemical treatment can be processed further by deacetylase. Efficiency of enzymatic deproteinization depends on the source of crustacean offal and the process conditions. Mild enzymatic treatment removes about 90% of the protein and carotenoids from shrimp-processing waste, and the carotenoprotein produced is useful for feed supplementation. In contrast, deproteinization of shrimp shells by Alcalase led to the isolation of chitin containing about 4.5% of protein impurities and recovery of protein hydrolysate.     

Mycelia of Mucor rouxii as a source of chitin and chitosan

Mycelia of M. rouxii may be used as a source of chitosan for medical, cosmetic and other purposes. The contents of chitin and chitosan in the mycelia from 2-day old cultures were 8.9 and 7.3% on a dry basis, respectively. Prolonged growth did not significantly influence the available amount of these polysaccharides. Chitin and chitosan isolation involved deproteinization of the mycelia with 2% NaOH solution at 90 °C for 2 h, extraction of chitosan with 10% acetic acid at 60 °C for 6 h and subsequent precipitation of chitosan at pH = 9.0. The recovery yield of aminosugars during the isolation process was about 94% of their total content in the mycelia. The chitosan contained 81.3% of glucosamine and its degree of acetylation was about 27.3%.     

酶在壳聚糖制备中的应用

综述了酶在壳聚糖制备中的应用;详细介绍了虾蟹壳酶法脱蛋白、甲壳素酶法脱乙酰及壳聚糖酶法降解这三方面的研究概况。     

壳聚糖金属配合物对黑曲霉的抑制活性研究

通过观察黑曲霉菌丝体的生长及孢子萌发情况,考察壳聚糖(CS)及壳聚糖锌(CS-Zn)、壳聚糖镍(CS-Ni)的抗真菌性能。结果表明：壳聚糖、壳聚糖锌和壳聚糖镍对黑曲霉孢子萌发和菌丝体生长均具有明显抑制作用,且壳聚糖金属配合物的抑菌效果比壳聚糖本身更强,其中壳聚糖镍最强。壳聚糖镍对黑曲霉的抑菌活性受壳聚糖分子质量、环境pH 值、质量浓度因素的影响较大。分子质量为5kD 的CS 制备的CS-Ni 抗真菌效果最好;CS-Ni 抑菌效果在pH3～7.5 时随pH 值降低而增强;随CS-Ni 质量浓度(0～0.75mg/mL)的增加而增强。     

虾壳不同部位制备甲壳素、壳聚糖的研究

本文采用红外光谱、扫描电镜作为为甲壳素、壳聚糖的性能参数的主要分析手段,分析了用EDTA脱钙法制备甲壳素、壳聚糖时,虾壳组织发生的变化以及由虾壳不同部位制得的甲壳素、壳聚糖在结构、性能参数等方面的异同。其结果为:本文所采用的EDTA脱钙法制备甲壳素、壳聚糖的工艺合理;由虾壳不同部位:虾头、虾身、虾足和虾头内容物三组试样所制得的甲壳素、壳聚糖其结构基本一致,但其脱乙酰度和相对分子量有较大差别,其中以虾头壳制备的甲壳素、壳聚糖的相对分子质量最大,而脱乙酰度则是虾足、虾头内容物所制得的试样较高。     

甲壳素与壳聚糖在印染工业中的应用

叙述了甲壳素与壳聚糖的化学性质。介绍了甲壳素作为印染助剂的特点以及在纺织品功能整理和印染废水处理中的用途。     

Purification and properties of extracellular chitinases from the parasitic fungus Isaria japonica

Two chitinases (P-1 and P-2) induced with colloidal chitin were purified from the culture supernatant of Isaria japonica by chromatography on DEAE Bio-Gel, chromatofocusing and gel filtration with Superdex 75 pg. The enzymes were electrophoretically homogeneous and estimated to have a molecular mass of 43,273 (+/-5) for P-1 and 31,134 (+/-6) for P-2 by MALDI-MS. The optimum pH and temperature was 3.5-4.0 and 50 degrees C for P-1 and 4.0-4.5 and 40 degrees C for P-2. P-1 acted against chitosan 7B (degree of deacetylation, 65-74%) = glycol chitin > colloidal chitin = chitosan 10B (degree of deacetylation, above 99%) and P-2 against chitosan 7B > glycol chitin = chitosan 10B > colloidal chitin in order of activity. The products of hydrolysis of chitin and chitosan hexamer were analyzed by MALDI-MS. The products from the chitin hexamer obtained with P-1 were almost all dimers with only a small amount of trimer whereas those obtained with P-2 were mainly trimers with some dimer and tetramer. No hydrolysis of chitosan hexamer was observed. High homology in the amino-terminal sequence for chitinase P-1 was exhibited by chitinases from Trichoderma harzianum, Candida albicans and Saccharomyces cerevisiae in the range of 48-39%. The highest homology for Chitinase P-2 was shown by an endochitinase from Metarhizium anisopliae of 66%, while 44% homology was exhibited by chitinases of Leguminosae plants.     

甲壳素传统法与微波法制备壳聚糖的比较

针对甲壳素脱乙酰制备壳聚糖采用的两种方法——微波法与传统法,从反应时间、壳聚糖的得率和品质(脱乙酰度和粘均分子量)等方面进行了比较分析。结果表明,甲壳素传统法一次脱乙酰反应很难制备脱乙酰度大于78%高粘均分子量的壳聚糖;与传统方法相比,甲壳素微波法脱乙酰制备壳聚糖不仅大大减少了反应时间,同时还能避免高温长时间处理导致壳聚糖产品的分子量和粘度下降,从而提高壳聚糖的质量指标。     

Chitin--the undisputed biomolecule of great potential

Of the truly abundant polysaccharides in Nature, only chitin has yet to find utilization in large quantity. Chitin is the second most abundant natural biopolymer derived from exoskeletons of crustaceans and also from cell walls of fungi and insects. Chitin is a linear beta 1,4-linked polymer of N-acetyl-D-glucosamine (GlcNAc), whereas chitosan, a copolymer of GlcNAc (approximately 20%) and glucosamine (GlcN, 80%) residues, is a product derived from de-N-acetylation of chitin in the presence of hot alkali. Chitosan is, in fact, a collective name representing a family of de-N-acetylated chitins deacetylated to different degrees. Both chitin/chitosan and their modified derivatives find extensive applications in medicine, agriculture, food, and non-food industries as well. They have emerged as a new class of physiological materials of highly sophisticated functions. Their application versatility is a great challenge to the scientific community and to industry. All these are the result of their versatile biological activity, excellent biocompatibility, and complete biodegradability in combination with low toxicity. Commercial availability of high-purity forms of chitin/chitosan and the continuous appearance of new types of chitin/chitosan derivatives with more and more useful and specific properties have led to an unlimited R&D efforts on this most versatile amino polysaccharide, chitin to find new applications, which are necessary to realize its full potential. Incidentally, this too has become an environmental priority. No doubt, chitin is surely an undisputed biomolecule of great potential.