A sustainable and nondestructive method to high-throughput decolor Lycium barbarum L. polysaccharides by graphene-based nano-decoloration.

Lycium barbarum L. polysaccharides (LBPs) with outstanding biological activities are of increasing interest. Traditional purification approaches are time-consuming and often involve toxic solvents that destroy the functionality and structure of polysaccharides. Herein, we report a sustainable and nondestructive strategy for purifying LBPs using graphene-based nano-decoloration. The amination of graphene oxide (GO) enables the resulted aminated reduced GO (NH2-rGO) with abundant sp2-hybridized carbon domains, displaying high adsorption capacity toward pigments in crude polysaccharides. As such, within 5 min, NH2-rGO can highly effectively and fast to decolor LBPs, with a high decoloration ratio of 98.72% and a high polysaccharides retention ratio of 95.62%. Importantly, compared with traditional decoloration methods, NH2-rGO is nondestructive toward LBPs and has good reusability. Moreover, it exhibited widespread-use decoloration performance to decolor several common plant species. Overall, our proposed nano-decoloration approach is a general-purpose, sustainable, and nondestructive method to purify LBPs.

An advanced and universal method to high-efficiently deproteinize plant polysaccharides by dual-functional tannic acid-feIII complex.

Deproteinization is a crucial step for the purification of polysaccharides from natural biomass. However, traditional deproteinization technologies often suffer from complicated operating processes and the usage of toxic chemical reagents. Herein, an advanced and universal deproteinization method based on dual-functional adsorbent consisted of preferential protein adsorption coating of tannic acid-FeIII (TA-FeIII) and magnetic Fe3O4 (Fe3O4@TA-FeIII, abbreviated as FTF NPs) was developed. The proposed FTF NPs showed remarkable efficiency to remove protein from Lycium barbarum L. polysaccharides (LBPs) with deproteinization ratio of 96%, higher than the typical Sevag method (85%). Detailed adsorption kinetics studies demonstrated deproteinization process reached equilibrium after 10 min, faster than other reported deproteinization adsorbents. Furthermore, FTF NPs are structurally and functionally nondestructive as regards LBPs without using organic reagents. Also, it exhibited widespread-use deproteinization performance to several common plant species. Therefore, the proposed nano-separation based on TA-FeIII complex is an advanced and universal tool to high-efficiently deproteinize plant polysaccharides.