title: The role of silica nanoparticles on long-term room-temperature stabilization of water-in-oil emulsions containing microalgae.
abstract: Prior research has demonstrated that microalgae can be stored for extended periods of time at room temperature in water-in-oil (W/O) emulsions stabilized by surface modified silica nanoparticles. However, little research has been done to examine the impact of nanoparticle concentration on emulsion stability. Such information is important for large-scale production of emulsions for microalgae storage and delivery. Studies were done to examine the impact of silica nanoparticle concentration on emulsion stability and identify the lower limit for nanoparticle concentration. Emulsion physical stability was determined using internal phase droplet size measurements and biological stability was evaluated using cell density measurements. The results demonstrate that nanoparticle concentrations as low as 0·5wt% in the oil phase can be used without significant losses in emulsion stability and microalgae viability.
  
  
  CONCLUSIONS
  Stabilization technologies are needed for long-term storage and application of microalgae in agricultural-scale systems. While prior work has demonstrated that water-in-oil emulsions containing silica nanoparticles offer a promising solution for long-term microalgae storage at room temperature, little research has been done to examine the impact of nanoparticle concentration on emulsion stability. Here, we show the effects of silica nanoparticle concentration on maintaining physical stability of emulsions and sustaining viable cells. The results enable informed decisions to be made regarding production of emulsions containing silica nanoparticles and associated impacts on stabilization of microalgae.
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA.|Bayer Crop Science, Davis, CA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Fernández
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA.
authors.forename: H
authors.initials: H
authors.lastname: Scher
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: VanderGheynst
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002708:Chlorella / Q000187:drug effects* / Q000502:physiology; D004655:Emulsions / Q000737:chemistry / Q000494:pharmacology*; D058086:Microalgae / Q000187:drug effects* / Q000502:physiology; D053758:Nanoparticles / Q000737:chemistry*; D009821:Oils / Q000737:chemistry / Q000494:pharmacology*; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D004655:Emulsions; D009821:Oils; D014867:Water; D012822:Silicon Dioxide
keywords: Chlorella; biological stability; microalgae storage; physical stability; silica nanoparticles