High-throughput screening assay for biological hydrogen production.

This paper describes a screening assay, compatible with high-throughput bioprospecting or molecular biology methods, for assessing biological hydrogen (H-2) production. While the assay is adaptable to various physical configurations, we describe its use in a 96-well, micro-titer plate format with a lower plate containing H-2-producing cyanobacteria strains and controls and an upper, membrane-bottom plate containing a color indicator and a catalyst. H-2 produced by cells in the lower plate diffuses through the membrane into the upper plate, causing a color change that can be quantified with a microplate reader. The assay is reproducible, semi-quantitative, sensitive down to at least 20 nmol of H-2, and largely unaffected by oxygen, carbon dioxide, or volatile fatty acids at levels appropriate to biological systems.