A Techno-economic Analysis of Polyhydroxyalkanoate and Hydrogen Production from Syngas Fermentation of Gasified Biomass DongWon Choi & David C. Chipman & Scott C. Bents & Robert C. Brown Received: 20 November 2008 / Accepted: 3 February 2009 / Published online: 27 February 2009 # Humana Press 2009 Abstract A techno-economic analysis was conducted to investigate the feasibility of a gasification-based hybrid biorefinery producing both hydrogen gas and polyhydroxyalkanoates (PHA), biodegradable polymer materials that can be an attractive substitute for conventional petrochemical plastics. The biorefinery considered used switchgrass as a feedstock and converted that raw material through thermochemical methods into syngas, a gaseous mixture composed mainly of hydrogen and carbon monoxide. The syngas was then fermented using Rhodospirillum rubrum, a purple non-sulfur bacterium, to produce PHA and to enrich hydrogen in the syngas. Total daily production of the biorefinery was assumed to be 12 Mg of PHA and 50 Mg of hydrogen gas. Grassroots capital for the biorefinery was estimated to be $55 million, with annual operating costs at $6.7 million. With a market value of $2.00/kg assumed for the hydrogen, the cost of producing PHA was determined to be $1.65/kg. Keywords Syngas fermentation . Synthesis gas fermentation . Polyhydroxyalkanoate . PHA . Techno-economic analysis . Hydrogen . ASPEN Plus . Rhodosprillum rubrum Introduction The term biorefinery, a concept analogous to a conventional petrochemical refinery, has been widely used to describe the chemical refining of many different processes where the feedstock is organic material from recent biological origin, i.e., biomass or biorenewable resources[1, 2]. Biorefineries offer an alternative to fossil organic-material-based petrochemical refineries but require new and innovative processing methods than those traditionally used in the petroleum industry [1, 2]. One innovative processing method is the gasification of biomass followed by syngas fermentation. Gasification is a thermochemical conversion of biomass into a flammable vapor mixture and char. If gasification is oxygen-blown at temperatures above 900 °C, the non-condensable vapor mixture is mostly hydrogen (H 2 ), carbon monoxide (CO), Appl Biochem Biotechnol (2010) 160:1032–1046 DOI 10.1007/s12010-009-8560-9 D. Choi : D. C. Chipman : S. C. Bents : R. C. Brown (*) Center for Sustainable Environmental Technologies, Iowa State University, 411 Martson Hall, Ames, IA 50011, USA e-mail: rcbrown@iastate.edu