Acetate utilization strategy in chain-elongating bacteria determines butyrate versus medium-chain carboxylate production (opens in new tab)

Chain-elongating bacteria (CEB) are a unique guild of anaerobes that upcycle organic waste into valuable short- and medium-chain carboxylic acids (MCCAs), enabling a circular bioeconomy. However, the metabolic rules that determine product chain length have remained elusive. Here we combine 13C isotope tracing, proteomics, enzyme assays and metabolic modelling to show that distinct acetate utilization strategies underlie the divergence between MCCA-producing CEB and those solely producing less...