Title: Comprehensive characterization of toxicity of fermentative metabolites on microbial growth

Abstract

Background Volatile carboxylic acids, alcohols, and esters are natural fermentative products, typically derived from anaerobic digestion. These metabolites have important functional roles to regulate cellular metabolisms and broad use as food supplements, flavors and fragrances, solvents, and fuels. Comprehensive characterization of toxic effects of these metabolites on microbial growth under similar conditions is very limited. Results We characterized a comprehensive list of thirty-two short-chain carboxylic acids, alcohols, and esters on microbial growth of Escherichia coli MG1655 under anaerobic conditions. We analyzed toxic effects of these metabolites on E. coli health, quantified by growth rate and cell mass, as a function of metabolite types, concentrations, and physiochemical properties including carbon number, chemical functional group, chain branching feature, energy density, total surface area, and hydrophobicity. Strain characterization revealed that these metabolites exert distinct toxic effects on E. coli health. We found that higher concentrations and/or carbon numbers of metabolites cause more severe growth inhibition. For the same carbon numbers and metabolite concentrations, we discovered that branched chain metabolites are less toxic than the linear chain ones. Remarkably, shorter alkyl esters (e.g., ethyl butyrate) appear less toxic than longer alkyl esters (e.g., butyl acetate). Regardless of metabolites, hydrophobicity of a metabolite, governed bymore » its physiochemical properties, strongly correlates with the metabolite’s toxic effect on E. coli health. Conclusions Short-chain alcohols, acids, and esters exhibit distinctive toxic effects on E. coli health. Hydrophobicity is a quantitative predictor to evaluate the toxic effect of a metabolite. This study sheds light on degrees of toxicity of fermentative metabolites on microbial health and further helps in the selection of desirable metabolites and hosts for industrial fermentation to overproduce them.« less

Authors:

Wilbanks, Brandon; Trinh, Cong T.

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• Search DOE PAGES for ORCID "0000-0002-8362-725X"

Publication Date:

Thu Nov 30 00:00:00 EST 2017

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE; USDOE Office of Science (SC), Biological and Environmental Research (BER), BioEnergy Science Center

OSTI Identifier:

1618692

Alternate Identifier(s):

OSTI ID: 1626989

Grant/Contract Number:  

AC05-000R22725; AC05-00OR22725; NSF#1553250

Resource Type:

Published Article

Journal Name:

Biotechnology for Biofuels

Additional Journal Information:

Journal Name: Biotechnology for Biofuels Journal Volume: 10 Journal Issue: 1; Journal ID: ISSN 1754-6834

Publisher:

Springer Science + Business Media

Country of Publication:

Netherlands

Language:

English

Subject:

Biotechnology & Applied Microbiology; Energy & Fuels