Chemical structure and mechanism of polysaccharide on Pb2+ tolerance of Cordyceps militaris after Pb2+ domestication

• Published in: International journal of biological macromolecules Vol. 165; pp. 958 - 969
• Main Authors: Song, Qiaoying, Zhu, Zhenyuan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2020
• Subjects: Cordyceps militaris; Extracellular polysaccharide; Mechanism research; Structure analysis; Extracellular polysaccharide; Mechanism research; Structure analysis; Cordyceps militaris
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.09.243

In this study, the purified polysaccharide (DCP-I) was extracted from Cordyceps militaris domesticated with Pb2+. After that, the structural feature and mechanism of lead resistance of DCP-I were investigated using novel approaches. The results showed that the average molecular weight of DCP-I was 1.206 × 103 kDa and mainly consist of Rhamnose, Galactose, Glucose, Galacturonic acid and Glucuronic acid in a molar ratio of 0.130:47.687:40.784:1.795:0.48. Besides, the main chain of DCP-I was composed by →6)-Galp-(1→, →4)-Glcp-(1→ and →1,4)-Glcp-(6→, while the side chain was →1)-Rhaf-(2→ and D-Glcp-(1→, and the DCP-I contained Alacturonic acid and Glucuronic acid. In addition, the result of Congo red test showed that DCP-I did not exist triple-helical structures. SEM, EDX and XPS analyses results showed that the functional groups of DCP-I related to C, H and O (-OH, -COOH and -C=O) could combined with Pb2+effectively. The adsorption processes were described by the Pseudo-second-order kinetic model (R2 = 0.9978) and Langmuir isotherm (R2 = 0.9979) for Pb2+ indicating that adsorption process of DCP-I to Pb2+ was a kind of single molecular layer chemical adsorption. •A novel polysaccharide DCP-I was isolated from Cordyceps militaris domesticated with Pb2+.•The structure of the DCP-I was accurately characterized.•The adsorption process of DCP-I to Pb2+ was single molecular layer chemical adsorption.•The functional groups of -OH, -COOH and -C=O could combined with Pb2+ effectively.