Lin Jieying, Deng Jinfeng, Huang Zhenyin, Dong Hanyu, Chang Aiping, Zhu Hu
Fujian-Taiwan Science and Technology Cooperation Base of Biomedical Materials and Tissue Engineering, Engineering Research Center of Industrial Biocatalysis, Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, Fujian, China.
ACS Omega. 2023 Feb 8;8(7):7163-7171. doi: 10.1021/acsomega.3c00172. eCollection 2023 Feb 21.
Sphingan WL gum (WL), a kind of exopolysaccharide, is produced by sp. WG, which was screened from sea mud samples of Jiaozhou Bay by our group. The solubility of WL was investigated in this work. First, 1 mg/mL of WL solution was stirred at room temperature for at least 2 h to obtain a uniform opaque liquid, and further the solution became clear with the increased NaOH and stirring time. Subsequently, the structural features, solubility, and rheological properties of WL before and after alkali treatment were compared systematically. FTIR, NMR, and zeta potential results indicate that the alkali causes acetyl group hydrolysis and carboxyl group deprotonation. XRD, DLS, GPC, and AFM results suggest that the alkali destroys the ordered arrangement and inter- and intrachain entanglement of polysaccharide chains. In the same case, 0.9 M NaOH-treated WL presents better solubility (stirring for 15 min to obtain a clarified solution) but, unsurprisingly, worsens rheological properties. All results demonstrated that the good solubility and transparency of alkali-treated WL will help promote its postmodification and application.
斯皮根 WL 胶（WL）是一种胞外多糖，由我们团队从胶州湾海泥样品中筛选出的 sp. WG 产生。本研究对 WL 的溶解性进行了考察。首先，将 1 mg/mL 的 WL 溶液在室温下搅拌至少 2 小时以获得均匀的不透明液体，随着 NaOH 用量增加和搅拌时间延长，溶液进一步变清。随后，系统比较了碱处理前后 WL 的结构特征、溶解性和流变学性质。傅里叶变换红外光谱（FTIR）、核磁共振（NMR）和zeta 电位结果表明，碱导致乙酰基水解和羧基去质子化。X 射线衍射（XRD）、动态光散射（DLS）、凝胶渗透色谱（GPC）和原子力显微镜（AFM）结果表明，碱破坏了多糖链的有序排列以及链间和链内缠结。在相同条件下，0.9 M NaOH 处理的 WL 具有更好的溶解性（搅拌 15 分钟可得到澄清溶液），但不出所料，其流变学性质变差。所有结果表明，碱处理后 WL 良好的溶解性和透明度将有助于促进其后期改性和应用。
