Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan.
Department of Chemical Engineering, National Institute of Technology, Ichinoseki College, Takanashi, Hagisho, Ichinoseki, Iwate 021-8511, Japan.
Carbohydr Polym. 2015 Dec 10;134:718-25. doi: 10.1016/j.carbpol.2015.08.066. Epub 2015 Aug 25.
This study examined the effects of sub- and supercritical water pretreatments on the physicochemical properties of crab shell α-chitin and its enzymatic degradation to obtain N,N'-diacetylchitobiose (GlcNAc)2. Following sub- and supercritical water pretreatments, the protein in the crab shell was removed and the residue of crab shell contained α-chitin and CaCO3. Prolonged pretreatment led to α-chitin decomposition. The reaction of pure α-chitin in sub- and supercritical water pretreatments was investigated separately; we observed lower mean molecular weight and weaker hydrogen bonds compared with untreated α-chitin. (GlcNAc)2 yields from enzymatic degradation of subcritical (350 °C, 7 min) and supercritical water (400 °C, 2.5 min) pretreated crab shell were 8% and 6%, compared with 0% without any pretreatment. This study shows that sub- and supercritical water pretreatments of crab shell provide to an alternative method to the use of acid and base for decalcification and deproteinization of crab shell required for (GlcNAc)2 production.
本研究考察了亚临界和超临界水预处理对蟹壳α-壳聚糖理化性质的影响，及其对获得 N,N'-二乙酰壳二糖（GlcNAc）2 的酶解作用。经过亚临界和超临界水预处理后，蟹壳中的蛋白质被去除，蟹壳残渣中含有α-壳聚糖和 CaCO3。延长预处理时间会导致α-壳聚糖分解。分别研究了纯α-壳聚糖在亚临界和超临界水预处理中的反应，与未经处理的α-壳聚糖相比，其平均分子量较低，氢键较弱。酶解亚临界（350°C，7 分钟）和超临界水（400°C，2.5 分钟）预处理的蟹壳，（GlcNAc）2 的产率分别为 8%和 6%，而未经任何预处理的产率为 0%。本研究表明，亚临界和超临界水预处理蟹壳为酸和碱脱钙脱蛋白提供了一种替代方法，从而用于生产（GlcNAc）2。
