Extracellular electron transfer increases fermentation in lactic acid bacteria via a hybrid metabolism
Abstract
Energy conservation in microorganisms is classically categorized into respiration and fermentation; however, recent work shows some species can use mixed or alternative bioenergetic strategies. We explored the use of extracellular electron transfer for energy conservation in diverse lactic acid bacteria (LAB), microorganisms that mainly rely on fermentative metabolism and are important in food fermentations. The LAB Lactiplantibacillus plantarum uses extracellular electron transfer to increase its NAD+/NADH ratio, generate more ATP through substrate-level phosphorylation, and accumulate biomass more rapidly. This novel, hybrid metabolism is dependent on a type-II NADH dehydrogenase (Ndh2) and conditionally requires a flavin-binding extracellular lipoprotein (PplA) under laboratory conditions. It confers increased fermentation product yield, metabolic flux, and environmental acidification in laboratory media and during kale juice fermentation. The discovery of a single pathway that simultaneously blends features of fermentation and respiration in a primarily fermentative microorganism expands our knowledge of energy conservation and provides immediate biotechnology applications.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 11, 2022
- Source ID
- 10.7554/elife.70684
Entities
People
- Andre Knoesen
- Caroline M Ajo-Franklin
- Eric T. Stevens
- James Nelson
- Maria L Marco
- Peter Finnegan
- Samuel H Light
- Sara Tejedor-Sanz
- Siliang Li
Organizations
- Cancer Prevention and Research Institute of Texas
- Lawrence Berkeley National Laboratory
- National Science Foundation
- Office of Naval Research
- Rice University
- United States Department of Agriculture
- United States Department of Energy
- University of California, Davis
- University of Chicago