Fig. 2.

Proposed scheme for the methanogenic degradation of amino acids in a psychrophilic up-flow anaerobic sludge blanket (UASB) reactor treating synthetic soy sauce wastewater. In each pathway, representative microbial population(s) are shown as a number in a panel. “Many” indicates that more than 7 representative populations have the corresponding metabolic capacities. Amino acids are shown as a common three-letter abbreviation according to the International Union of Pure and Applied Chemistry (IUPAC). Other abbreviations: PRPP, 5-phospho-alpha-d-ribose 1-diphosphate; THF, tetrahydrofolate; 5-MTHF, 5-methyltetrahydrofolate TRDred, reduced thioredoxin; TRDoxi, oxidized thioredoxin; Fum, fumarate; Pyr, pyruvate; Oxa, oxaloacetate.