Base-dependent flocculant treatment improves the extraction of latex from guayule

Abstract

The extraction of high-quality latex from guayule (Parthenium argentatum) is highly mechanized. Multiple purification steps are currently required to eliminate non-latex solids and soluble proteins from homogenized shrub to achieve medical-grade guayule latex purity. The present study evaluates flocculant systems to enhance filtration and reduce centrifugal clarification, hence making the extraction process simpler and more efficient. Five polyamine flocculants were tested at four concentrations in homogenates prepared in NH4OH buffer and filtered either through cheesecloth or a mechanical press. The efficiency of the highest latex-yielding flocculant, 1000 ppm Cysep 2707, was enhanced 12-fold by adding 0.1% alginate. Four additional cationic flocculants more effectively sedimented non-rubber solids in KOH-based homogenate and yielded more than double the amount of latex. Additionally, recycling of the bagasse waste enhanced latex yield when fed back into the extraction process. Use of ionic flocculants can enhance latex yield and facilitate commercialization of medical grade guayule latex.