摘要
将壳聚糖置于不同盐酸浓度的反应体系中进行降解反应,制备得到不同聚合度的壳寡糖混合物;采用凝胶过滤法分离混合物,旨在获得特定聚合度(DP=5-6)的壳寡糖。实验表明:在不同温度(40℃、60℃、80℃)和不同盐酸浓度(6 mol/L、9 mol/L、11 mol/L)下,壳聚糖均能被有效的降解;不同降解液中各种聚合度壳寡糖组成不一;其中,在9mol/L盐酸和60℃的反应条件下,降解液中壳五糖和壳六糖含量最高,达到16.2%。采用以葡聚糖凝胶Sephadex G-15为介质的层析法,实现了对降解液中壳低聚糖混合物的初步分离,获得主要含壳五糖和壳六糖的组分。该组分经高效液相色谱法鉴定,除预期的壳五糖和壳六糖外,还含有另一未知化合物。通过13C和1H核磁共振分析,并结合专一性壳聚糖酶的酶解实验,对其进行表征和鉴定,结果表明:该化合物为聚合度为7的壳七糖。
This study outlines a method to prepare chitooligosaccharides with a specific degree of polymerization （5 -6）. It was carried out by hydrochloric acid hydrolysis in a chitosan-degradcd system and a following procedure by gel filtration chromatography to fractionate chitosan oligomers. The degradation of ehitosan over a range of temperatures （40 ℃, 60 ℃ and 80 ℃ ） and hydrochloric acid concentrations （ 6 mol/L, 9 mol/L and 11 moL/L） was investigated. The results showed that chitosan was degraded effectively and various chitooligosaccharide mixtures with different oligomer constitutions were obtained. Among them, the optimum conditions were 9 mol/L HC1 at 60 ℃ and the yield of chitopentaose and chitohexose reached 16.2%. A procedure using Sephadex G-15 onto size-exclusion column was further developed to narrow the range of oligomers and obtain expected fraction containing mainly chitosan pentamer and hexamer detected by thin layer chromatography. Furthermore, it was identified by high performance liquid chromatography. Alongside peaks for chitopentaose and chitohexaose, a new peak designating an unknown compound occurred. It was identified as ehitooligosaeeharide by ^13C and 1H nuclear magnetic resonance. Enzymatic depolymeriza- tion by chitosanase produced mainly trimer and tetramer, further confirming the presence of a heptamer.
出处
《上海海洋大学学报》
CAS
CSCD
北大核心
2013年第4期634-640,共7页
Journal of Shanghai Ocean University
基金
上海市科学技术委员会工程中心建设项目(11DZ2280300)
关键词
壳聚糖
壳寡糖
酸水解
聚合度
chitosan
chitooligosaccharides
acid hydrolysis
degree of polymerization
