应用FTIR和NMR研究短梗霉多糖分子结构

Studies on Structure of Pullulan from Aureobasidium pullulans by FTIR and NMR

短梗霉多糖是出芽短梗霉产生的一种胞外多糖，具有极好的成膜、成纤维、阻气、粘接、易加工、无毒性等特性，是微生物多糖中最令人瞩目的多糖之一．本研究应用ＦＴＩＲ和ＮＭＲ技术对由出芽短梗霉胞外产生的短梗霉多糖进行了分析．短梗霉多糖的红外光谱（４０００～４００ｃｍ－１），具有明显的多糖特征吸收峰，证明多糖是由α－Ｄ－吡喃葡萄糖残基组成．应用先进的一维和二维核磁共振技术，在绝对温度３４３Ｋ下获得短梗霉多糖１Ｈ－ＮＭＲ谱和１３Ｃ－ＮＭＲ谱，确证短梗霉多糖的结构单元是α－１，４麦芽三糖。

Pullulan, a kind of exopolysaccharides produced by Aureobasidium pullulans, has good film forming, high adhesion,low digestibility,nontoxicity and other characters and is used widely in food,pharmaceutical,chemical,petrochemical and light industries etc.It is even drawing more and more attentions.In this paper,the structure of pullulan was studied using fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) techniques. There were the specific characteistic absorbance peaks in the pullulan infrared spectra from 4 000 to 400 cm 1 in the FTIR assay,which indicated that the pullulan consisted of α D glucopyranoses. With the aid of the technique of the one dimensional and two dimensional nuclear magnetic resonance, the clear spectra of 1H NMR, 13 C NMR, 13 C 1H COSY had been recorded at the temperature of 343K.The results confirmed that the unit of pullulan was α 1,4 maltritose and successfully assigned the chemical shifts of pullulan in the 1H NMR and 13 C NMR spectra.