Chitin oligosaccharides production fromenzymatic hydrolyzing crab shells

In order to find an environment friendly way of producing chitin oligosaccharides from pretreated crab shells, we hydrolyze emulsified pretreated crab shells with chitinase whose gene is from Aspergillus fumigatus YJ-407 and cloned and expressed in E. coli (Xiaet al., 2001; Anonymous, 2008). After optimizing chitinase enzymatichydrolysis conditions using Orthogonal Experimental Design, we conduct the hydrolysis experiment under the conditions which is adding 5 g chitinase to every 0.022 g emulsified crab shells and keeping this 2ml solution in 50 ◦C and pH 5.0 environment. After 75 min reaction, we analyze the hydrolyzed products by HPAECPAD (Anonymous, 2008) and TLC (Anonymous, 2008). The results showed that crab shells without fierce acid and alkali pretreatment can be readily hydrolyzed by this chitinase. There are mainly three kinds of chitin oligosaccharides in the hydrolyzed solution. They are N-acetyl-glucosamine, chitobiose and chitotriose, and chitobiose is the most abundant product. The production efficiencies are separately 7.21%, 1.15%, and 0.29% for chitobiose, N-acetyl-glucosamine and chitotriose. The result can be used as a base for the more valuable development about the trash crab shells