Development of a compact stacked flatbed reactor with immobilized high-density bacteria for hydrogen production

We have developed a compact stacked flatbed reactor (CSFR) composed of several pieces of agar plates containing an H 2 -producing bacterium, Escherichia coli. The bacterium was immobilized at high density (8 mg dry cell/ml agar) in the flatbed agar plate with 1.5–2 mm in thickness, producing H 2 under fermentative conditions. These flatbeds were vertically assembled to enable the easy extraction of products from the reactor. In batch reaction at 100 mM glucose as a starting substrate, more than 90% of glucose was consumed, resulting in the maximum H 2 -production rate of 6.7 l H 2 / g dry cell/l reactor/h and total H 2 yield of 1.2 mol H 2 / mol glucose .