Chitin is the second-most abundant bioresource and widely used in the food, agricultural, biomedicine, and other industries. However, under the mutual restriction of extraction cost and environmental protection, it is relatively difficult to prepare chitin from natural sources by pure separation. The aim of this study is to extract chitin from fresh crab shell waste by decalcification (DC) and deproteinization (DP) using glutamic acid and alkaline protease. The optimum technological conditions for DC and DP were as follows: (1) 5% (w/v) glutamic acid solution was used as decalcifying agent, the ratio of material to liquid was 1:10 (m/v), and the ash content in chitin was 0.83 ± 0.027% after decalcification at 75° C for 12 h. (2) Using alkaline protease as enzymatic hydrolyzer, 1500 U of alkaline protease was added per gram of crab shell. Under the conditions of material-liquid ratio of 1:10 (m/v) and pH value of hydrolysate of 9.0, N content in chitin was 6.63 ± 0.10% after 6 h of enzymatic hydrolysis at 55° C. And the extraction rate of chitin was 92.25 ± 0.51%. As a decalcifying agent, glutamic acid could be recycled with a recovery rate of 77.42 ± 2.16%. Calcium carbonate in crab shell was converted into calcium hydrogen phosphate by calcium glutamate, and protein into amino acids and polypeptides, which could be used as feed additives. The "glutamic acid-enzymolysis" for extracting chitin from crab shell is a relatively closed process, which has the advantages of mild reaction, greatly reducing the discharge of three wastes and high comprehensive utilization rate of raw materials.

中文翻译：

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从蟹壳废料中提取甲壳质及其副产物回收的“谷氨酸酶解”工艺研究。

甲壳质是第二大生物资源，广泛用于食品，农业，生物医学和其他行业。然而，在提取成本和环境保护的相互制约下，通过自然分离从天然来源制备甲壳质相对困难。这项研究的目的是使用谷氨酸和碱性蛋白酶通过脱钙（DC）和脱蛋白（DP）从新鲜蟹壳废物中提取甲壳质。DC和DP的最佳工艺条件如下：（1）使用5％（w / v）的谷氨酸溶液作为脱钙剂，物料与液体的比例为1:10（m / v），灰分75°C脱钙12 h后，几丁质中甲壳素的含量为0.83±0.027％。（2）使用碱性蛋白酶作为酶水解器，每克蟹壳添加1500U碱性蛋白酶。在1:10（m / v）的料液比和9.0的水解液pH值的条件下，甲壳质中的N含量在55°C酶水解6 h后为6.63±0.10％。几丁质为92.25±0.51％。谷氨酸作为脱钙剂可以回收利用，回收率为77.42±2.16％。蟹壳中的碳酸钙被谷氨酸钙转化为磷酸氢钙，蛋白质转化为氨基酸和多肽，可用作饲料添加剂。从蟹壳中提取甲壳质的“谷氨酸酶解”是一个相对封闭的工艺，具有反应温和，大大减少了三废的排放，原料综合利用率高的优点。55℃下酶解6h后，几丁质中的N含量为6.63±0.10％。几丁质的提取率为92.25±0.51％。谷氨酸作为脱钙剂可以回收利用，回收率为77.42±2.16％。蟹壳中的碳酸钙被谷氨酸钙转化为磷酸氢钙，蛋白质转化为氨基酸和多肽，可用作饲料添加剂。从蟹壳中提取甲壳质的“谷氨酸酶解”是一个相对封闭的过程，反应温和，大大减少了三废的排放，原料综合利用率高。55℃下酶解6h后，几丁质中的N含量为6.63±0.10％。几丁质的提取率为92.25±0.51％。谷氨酸作为脱钙剂可以回收利用，回收率为77.42±2.16％。蟹壳中的碳酸钙被谷氨酸钙转化为磷酸氢钙，蛋白质转化为氨基酸和多肽，可用作饲料添加剂。从蟹壳中提取甲壳质的“谷氨酸酶解”是一个相对封闭的过程，反应温和，大大减少了三废的排放，原料综合利用率高。谷氨酸可回收利用，回收率为77.42±2.16％。蟹壳中的碳酸钙被谷氨酸钙转化为磷酸氢钙，蛋白质转化为氨基酸和多肽，可用作饲料添加剂。从蟹壳中提取甲壳质的“谷氨酸酶解”是一个相对封闭的过程，反应温和，大大减少了三废的排放，原料综合利用率高。谷氨酸可回收利用，回收率为77.42±2.16％。蟹壳中的碳酸钙被谷氨酸钙转化为磷酸氢钙，蛋白质转化为氨基酸和多肽，可用作饲料添加剂。从蟹壳中提取甲壳质的“谷氨酸酶解”是一个相对封闭的工艺，具有反应温和，大大减少了三废的排放，原料综合利用率高的优点。