(228v) Production and Kinetics of Metallic Nanoparticles from Phototrophic Cell Culture

Biosynthesis of nanomaterials, such as noble metal nanoparticles, has experienced a tremendous expansion during the last two decades. Among the proposed biological production platforms, algae have attracted increasing attention from research scientists worldwide because they represent a trend towards greener, more sustainable processes which reduce or eliminate potentially toxic solvents and reagents, minimize energy requirements and use renewable natural resources. These â??greenâ? synthesized nanobiomaterials can be used to fabricate biosensors, therapy and diagnostics tools, medical imaging agents, as well as tissue engineering scaffolds and biomaterials. Indeed, microalgae are produced in photobioreactors in aqueous solutions at ambient temperatures and pressures and at a near neutral pH. Additionally, under the appropriate bioprocess conditions phototrophic algal cell cultures can catalyze the conversion of soluble metal cations, such as silver cation (Ag^+­), to metallic silver nanoparticles (Ag⁰ NPs). It is proposed in the literature that the reducing power required to drive this reaction is derived from the electron flux produced in the algaeâ??s photosynthetic apparatus, or specifically, in the thylakoid membrane. Furthermore, the as-produced NPs show a narrow size distribution because the thylakoid membrane provides a shape-directing template. This research carries out controlled photobioreactor cultivations for the biological production of Ag⁰ NPs. Photon, mass and energy balances are used to determine rate NP production kinetics and identify potential rate-limiting steps. This study represents a path forward towards the scalable, sustainable, economical production of metallic NPs from photosynthetic cell culture.