Electrochemically applied potentials induce growth and metabolic shift changes in the hyperthermophilic bacterium Thermotoga maritima MSB8.

Bioelectrochemical systems are an attractive technology for regulating microbial activity. The effect of an applied potential on hydrolysis of starch in Thermotoga maritima as a model bacterium was investigated in this study. A cathodic potential (-0.6 and -0.8 V) induced 5-h earlier growth initiation of T. maritima with starch as the polymeric substrate than that without electrochemical regulation. Moreover, metabolic patterns of starch consumption were altered by the cathodic potential. While acetate, H, and CO were the major products of starch consumption in the control experiment without electrolysis, lactate accumulation was detected rather than decreased acetate and H levels in the bioelectrochemical system experiments with the cathodic potential. These results indicate that the applied potential could control microbial activities related to the hydrolysis of polymeric organic substances and shift carbon and electron flux to a lactate-producing reaction in T. maritima.