Isolation and Investigation of Natural Rubber Latex from Taraxacum kok-saghyz with a High Solid Content

Abstract

Roots of Taraxacum kok-saghyz (TKS) are a promising alternative source of natural rubber latex (NRL). This study demonstrated the novel possibility of extracting, stabilizing, and concentrating NRL from roots of TKS with a high solid content. In addition, some colloidal characteristics of the isolated products, which are of interest for latex processing, were determined. A scaled-up extraction sequence based on previous studies of flow extraction was applied with a setup comprised of an industrial slicer, stirring stations, and a hydraulic press. Significant amounts of natural rubber (NR) were separated along with removed biomass. Stabilization of NRL was successfully maintained during latex isolation using ammonia-free stabilizing solutions consisting of an ethanolamine/ethanolamine hydrochloride (ETA/ETA-HCl) buffer, sodium oleate, sodium sulfite, and benzalkonium chloride. Purified and preconcentrated raw latex was obtained through repeated creaming and redilution. While a direct further concentration of raw latex proved difficult, the isolation of latex with a high solid content was achieved through redilution before the final centrifugation. Gravimetry indicated a solid content of >54%. The products were characterized by a high viscosity, and dilution was possible without coagulation. ζ-potential (ZP) was determined to be −60 mV and approved the successful stabilization of high solid latex. Dynamic light scattering (DLS) confirmed the possibility of maintaining a bimodal particle size distribution (PSD) with hydrodynamic diameters of 104–231 nm for the first mode and 522–830 nm for the second mode.

Insight into Mechanical Extraction Mechanisms of Natural Rubber Extraction from Taraxacum kok-saghyz

“…For the NR extraction from TKS-root material, the following groups of extraction methods were previously used: Solvent extraction, , enzymatic pre-extraction of lignocellulose, − bacterial/fungal pre-extraction of lignocellulose, − latex extraction, − or a variation of different mechanical extraction methods. − For mechanical extraction, Eskew , developed a two-stage ball mill (pebble mill) extraction. The function of the first stage was to separate softened or degraded cells from rubber tubes, thus elevating the rubber content relative to dry mass in the ball mill and to exclude biomass so that a higher throughput was achieved in the extraction system .…”

Extraction process and characterization of Taraxacum kok-saghyz (TKS) latex

“…Researches on latex extraction are also focused by some scholars because of its simplicity, efficiency, and high purity [ 7 , 17 , 18 ]. When extracting the TKS latex, it is necessary to prevent the latex from agglomeration during the extraction process while ensuring the freshness of the roots, which further increases the difficulty of latex extraction.…”