Yeast Cell Wall Particle Encapsulation of Pro-Terpene Payloads

E. Soto, F. Rus, G. Ostroff
University of Massachusetts Medical School,
United States

Keywords: yeast cell wall particle, terpene, controlled release, microparticle encapsulation


Terpenes are naturally occurring organic compounds produced by plants that have long been recognized for their insecticidal, antibacterial, antifungal, and antioxidant properties. Some terpenes are classified as Generally Recognized As Safe (GRAS) materials and are used in the medical, agricultural, food, consumer and cosmetic industries. However, applications of terpenes have been limited by terpene volatility and poor water solubility resulting in challenges to produce high concentration terpene products without the use of surfactants or alcohols. We have developed methods using Yeast Cell Wall Particles (YCWPs), 3-5 µm hollow and porous microspheres derived from the cell walls of Baker’s yeast (Saccharomyces cerevisiae), to efficiently encapsulate high levels of terpenes. Terpenes are loaded inside the hydrophobic YCWP cavity by passive diffusion through the porous cell walls. Sustained terpene release from YCWPs is the reverse process and is a function of terpene water solubility. This approach has been successfully implemented to develop and commercialize a YCWP-terpene based fungicide for agricultural applications (1-3). To obtain stimuli-responsive control of terpene release, we have synthesized four pro-terpene compounds (carvacrol, geraniol, eugenol, and thymol) (4). The pro-terpenes are (1) solid at room temperature (in contrast three of these terpenes are liquid and volatile at room temperature), (2) water insoluble, (3) stable at neutral pH, and (4) susceptible to chemical (pH) or enzymatic hydrolysis of a biodegradable linker providing for controlled terpene release. YCWP pro-terpene encapsulated materials were synthesized, characterized for stability and controlled terpene release, and their antibacterial (carvacrol) and antifungal (geraniol, eugenol, thymol) properties were evaluated in vitro. This new approach will allow us to use YCWPs encapsulated pro-terpenes to develop products for a broad range of controlled release terpene applications in human and animal health, and agriculture and consumer products. References (1) Franklin, L; Cloud, E; Knapp, L; Ostroff, G. Compositions containing a hollow glucan particle or a cell wall particle encapsulating a terpene component, methods of making and using them. US20100040656A1 (2) Franklin, L; Ostroff, G. Nematicidal compositions and methods of using them. US9655360B2 (3) Franklin, L; Ostroff. G. Compositions and methods comprising terpenes or terpene mixtures selected from thymol, eugenol, geraniol, citral, and l-carvone. US9439416B2 (4) Soto, E; Ostroff, G. Yeast Cell Wall Particle encapsulation of biodegradable pro-payloads. U.S. Provisional Patent Application Serial No. 62/644,219