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Title: Metabolism and Evolution of a Biofuel-Producing Microbial Coculture

Technical Report ·
DOI:https://doi.org/10.2172/1459596· OSTI ID:1459596
 [1]
  1. Indiana Univ., Bloomington, IN (United States)

Specialized features of individual microbial species can be combined in coculture to produce useful fuels and chemicals. Cocultures can also be used to address how microbes cooperate in nature through metabolic interactions but with a level of experimental control that is not possible in natural systems. However, the challenge of maintaining stable microbial relationships and the limited assays available for studying single strains in consortia has impeded progress in characterizing and implementing synthetic communities. In this project, my lab developed a stable and highly reproducible H2 biofuel-producing coculture between fermentative Escherichia coli and phototrophic Rhodopseudomonas palustris. In this coculture each species provides or 'cross-feeds' a nutrient that the other requires for growth. My lab used this coculture along with mathematical modeling to uncover basic principles governing mutualistic interactions between microbes, including (i) the potential for cross-fed nutrients to alternatively act as toxins depending on the level to which they are produced, (ii) how mutualistic cross-feeding can establish and persist in nutrient-deprived environments where the highest biofuel yields were observed, and (iii) the potential for competition between mutualistic partners for a cross-fed nutrient when that nutrient holds value for both species involved. In using ethanol-producing Zymomonas mobilis in place of E. coli in the coculture, my lab also discovered that Z. mobilis can use N2 gas as a nitrogen source, with potential cost-savings for the industrial production of cellulosic ethanol.

Research Organization:
Indiana Univ., Bloomington, IN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
DOE Contract Number:
SC0008131
OSTI ID:
1459596
Report Number(s):
DOE-INDIANA-08131
Resource Relation:
Related Information: https://github.com/McKinlab/Coculture-Mutualismhttps://patents.google.com/patent/WO2016109286A1/en
Country of Publication:
United States
Language:
English