Stickland fermentation
From Biocrawler, the free encyclopedia.
Stickland fermentation is coupled oxidation and reduction of amino acids to organic acids. The electron donor amino acid is oxidised to a volatile fatty acid one carbon molecule shorter than the original amino acid (e.g., alanine; C3 → acetate; C2). The electron acceptor amino acid is reduced to a volatile fatty acid the same length as the original amino acid (e.g., glycine; C2 → acetate; C2). In this way, amino acid fermenting microbes can avoid using hydrogen ions as electron acceptors to produce hydrogen gas. Amino acids can be Stickland acceptors, Stickland donors, or act as both donor and acceptor. Only histidine cannot be fermented by Stickland reactions, and is oxidised. With a typical amino acid mix, there is a 10% shortfall in Stickland acceptors, which results in hydrogen production. Under very low hydrogen partial pressures, increased uncoupled anaerobic oxidation has also been observed.
