Economic assessment of an integrated bioethanol–biodiesel–microbial fuel cell facility utilizing yeast and photosynthetic algae

Abstract

A strategy for the integration of a novel CO 2 photosynthetic culture and power generation system into a commercial bioethanol plant is presented. Photosynthetic microalgae column photobioreactors, acting as cathodic half cells, are coupled with existing yeast fermentors at a bioethanol plant, acting as anodic half cells, to create coupled microbial fuel cells. The microalgae photobioreactors also sequester CO 2 emitted by the yeast fermentors. Incorporating microbial fuel cells into an existing bioethanol plant generates some of the power used in bioethanol production and the microalgae species Chlorella vulgaris contains oil, which acts as a byproduct for the production of biodiesel. The goal of the study is to determine the required design specifications of novel, airlift PBR cathodes to make the integrated system economically feasible at an existing bioethanol plant. Data from previous experimental studies was used to develop the optimum integration strategy. The reported parameters include PBR size, number of integrated MFCs, fuel cell outputs, oil (for biodiesel) production rate, and CO 2 consumption rate.