Techno-Economic Feasibility of Polyhydroxybutyrate (PHB) Production from Corn Stover

Abstract

This research evaluated the techno-economic feasibility of polyhydroxybutyrate (PHB) production using corn stover as a substrate for the fermentation process. The target PHB plant production was set at 1000 t PHB per yr, with a daily production of about 3 t PHB. The required corn stover biomass was around 12 000 t per yr. The economic analysis of this study suggested that 91.13 M US$ is needed to put up the targeted plant production capacity, with 94% of the total investment to be allotted to the direct fixed capital cost. Annual operating cost was rated at 4.71 M US$ per yr. Fixing the return of investment (ROI) at 7%, the base selling price of PHB was computed at 11.80 US$ kg -1 . On the other hand, increasing the PHB productivity from 0.34 g PHB L -1 d -1 of the batch operation to a 1.20 g PHB L -1 d -1 of the continuous process may reduce the PHB price to 6.55 US$ kg -1 , which is comparable to the literature. The average cost of PHB was 7.50 US$ kg -1 . To further lower the PHB price, higher sugar yield and productivity, lower enzyme cost, lower pretreatment energy cost, and higher PHB productivity must be established. Furthermore, low-cost sugar or carbon-rich substrate without the need for rigorous upstream processing may also be identified and investigated to produce PHB. Overall, PHB production using agricultural substrates such as corn stover is competitive and feasible.