Stickland fermentation or TheStickland Reaction[1] is the name for a chemical reaction that involves the coupledoxidation andreduction ofamino acids to organic acids. Theelectron donor amino acid is oxidised to a volatilecarboxylic acid one carbon atom shorter than the original amino acid. For example,alanine with a three carbon chain is converted toacetate with two carbons. The electron acceptor amino acid is reduced to a volatile carboxylic acid the same length as the original amino acid. For example,glycine with two carbons is converted to acetate.
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. Onlyhistidine 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 inhydrogen production. Under very low hydrogen partial pressures, increased uncoupled anaerobic oxidation has also been observed.It occurs in proteolytic clostridia such as:C. perfringens,Clostridioides difficile,C. sporogenes,andC. botulinum.
Additionally,sarcosine andbetaine can act as electron acceptors.[2]
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