Related Experiment Video
Updated: Mar 20, 2026

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System
Published on: August 23, 2024
Coexistence of two d-lactate-utilizing systems in Pseudomonas putida KT2440
Yingxin Zhang1, Tianyi Jiang1,2, Binbin Sheng1
1State Key Laboratory of Microbial Technology and School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China.
Abstract:
It is advantageous for rhizosphere-dwelling microorganisms to utilize organic acids such as lactate. Pseudomonas putida KT2440 is one of the most widely studied rhizosphere-dwelling model organisms. The P. putida KT2440 genome contains an NAD-dependent d-lactate dehydrogenase encoding gene, but mutation of this gene does not play a role in d-lactate utilization. Instead, it was found that d-lactate utilization in P. putida KT2440 proceeds via a multidomain NAD-independent d-lactate dehydrogenase with a C-terminal domain containing several Fe-S cluster-binding motifs (Fe-S d-iLDH) and glycolate oxidase, which is widely distributed in various microorganisms. Both Fe-S d-iLDH and glycolate oxidase were identified to be membrane-bound proteins. Neither Fe-S d-iLDH nor glycolate oxidase is constitutively expressed but both of them can be induced by either enantiomer of lactate in P. putida KT2440. This study shows a case in which an environmental microbe contains two types of enzymes specific for d-lactate utilization.
Related Concept Videos
Inducible Operons: lac Operon
Fates of Pyruvate
In aerobic organisms, pyruvate is metabolized via the citric acid cycle to produce reduced coenzymes NADH and FADH2. These coenzymes are then oxidized in the electron transport chain to produce ATP and, in the process, regenerate the NAD+ and FAD. As seen in some cell types and organisms, fermentation...
Other Glycolytic Pathways
Microbial Fermentation

