魔芋葡甘聚糖/可得然胶复合气凝胶的生物降解性研究

Study on the Biodegradability of Konjac Glucomannan/Curdlan Composite Aerogel

本文以魔芋葡甘聚糖(KGM)和可得然胶(CUD)两种生物多聚物为基材,使用溶胶-凝胶法和真空冷冻干燥制备了不同质量比(KGM/CUD,1:0.6、1:0.9、1:1.2)的复合气凝胶。利用筛选出的四种优势菌株黑曲霉(Fen)、扩展青霉(L)、意大利青霉(B3)、芽孢杆菌(WE-3)对复合气凝胶进行降解,探究其降解形态、重量变化、微观形貌、分子变化、热稳定性及菌株生长适应性。结果表明,经不同种菌株降解后,气凝胶外观塌陷、皱缩、表面覆盖菌体;气凝胶被降解过程中可能由于KGM的强吸湿性而吸收环境中水分,促进了降解过程;降解后无新基团产生,多糖长链被降解为短链;电镜扫描图显示气凝胶多孔结构被破坏,三维网络结构坍塌;热力学分析表明气凝胶热稳定性明显降低;真菌Fen、L和B3适应于复合气凝胶环境的生长,细菌WE-3难以适应。本研究将为多糖复合材料的生物降解提供理论参考。

In this paper,konjac glucomannan(KGM) and curdlan(CUD) were used to prepare biomass aerogels with different mass ratios(KGM/CUD,K1C0.6,K1C0.9,K1C1.2) based on sol-gel and vacuum freeze-drying methods.The four dominant strains of Aspergillus niger(Fen),Penicillium expansum(L),P.italicum(B3) and Bacillus sp.(WE-3) were used to degrade the composite aerogel,and the degradation morphology,weight change,microscopic morphology,molecular change,thermal stability and strain growth adaptability were investigated.The results showed that the aerogels collapsed and shrinking with abundant thallus on the surface.During the degradation process of the aerogel,the water from the environment was absorbed by the hygroscopicity of KGM,and the degradation process would be accelerated.FTIR showed that the long chains of polysaccharides were degraded into short chains after degradation,and no new groups were produced.SEM pictures expressed that the porous structure of aerogel was destroyed and the three-dimensional network structure collapsed.DSC analysis showed that the thermal stability of aerogel significantly decreased.The fungi Fen,L and B3 were suitable for the growth of KC aerogel environment,while the bacteria WE-3 struggled to adapt.This research was expected to provide theoretical reference for the biodegradation of polysaccharide composites.