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Factors affecting the recovery yield and the purity of n-acetyl glucosamine from chitin hydrolysate

In this study, different ratio of ethanol to hydrolysates obtained by hydrolyzing chitin by chitinase as well as concentration of hydrolysates was investigated to find the optimal value. The result showed that the optimal ratio of absolute ethanol to hydrolysates was 9:1. | Journal of Science and Technology 54 (4A) (2016) 23-30 FACTORS AFFECTING THE RECOVERY YIELD AND THE PURITY OF N-ACETYL GLUCOSAMINE FROM CHITIN HYDROLYSATE Dang Thi Huong1, 2, *, Le Thanh Ha1, Pham Thu Thuy1 1 School of Biotechnology and Food Technology, Hanoi University of Science and Technology, 1 Dai Co Viet, Hanoi, Vietnam 2 Faculty of Food Technology, Ha Tay Community College, Xuan Sen Village, Thuy Xuan Tien Commune, Chuong My, Hanoi, Vietnam * Email: huongbomon@gmail.com Received: 15 August 2016; Accepted for publication: 5 October 2016 ABSTRACT In this study, different ratio of ethanol to hydrolysates obtained by hydrolyzing chitin by chitinase as well as concentration of hydrolysates was investigated to find the optimal value. The result showed that the optimal ratio of absolute ethanol to hydrolysates was 9:1. The further increase of this ratio up to 11:1 resulted only in insignificant increase of N-acetylglucosamine (NAG) recovery yield from 74.47 % to 75.39 % and NAG purity from 93.25 % to 93.44 %. Concentration of hydrolysate also affected the NAG recovery yield and NAG purity. The impurity of crystallization by cooling down the hydrolysates appeared only when hydrolysate was concentrated at a certain level. The mass of crystallization impurity was increased sharply from 0 to 0.082 mg/ml when hydrolysate’s concentration was increased significantly from 1 to 7.9 fold, then slightly from 0.082 to 0.093 mg/ml as its concentration further increased up to 15.7 fold. Higher concentration of hydrolysate resulted in lower recovery yield but purer product. According to HPLC analysis, 93.25 % of NAG purity with recovery yield 74.47% was obtained at optimal ethanol/hydrolysates ratio and optimal concentration of hydrolysate. Keywords: N-Acetyl-D-glucosamine NAG, purification, crystallization, precipitation. 1. INTRODUCTION N- Acetyl Glucosamine (GlcNAc or NAG), the monomer unit of polymeric chitin possesses therapeutic potential for treatment of .