# Microbial Origin of Breath Volatile Metabolites

> **NIH NIH R21** · WASHINGTON UNIVERSITY · 2021 · $208,438

## Abstract

ABSTRACT
Gut microbial communities influence multiple facets of human health, impacting common disorders such as
obesity, autoimmune diseases, and allergies. These discoveries were enabled by the application of
metagenomic sequencing and mass spectrometric techniques to human fecal samples, leading to remarkable
insights into the interplay between gut microbial communities and human health. However, a major barrier to
translating our growing knowledge about the gut microbiota and its functions to the patient-care setting
is the difficulty in obtaining, storing, processing and analyzing fecal samples. Volatile organic compounds
(VOCs) are present in exhaled breath and are produced by many microbes. By coupling a new method for
analyzing the VOC composition of mouse breath samples with our gnotobiotic model, we find that breath VOC
patterns reflect the gut microbial communities. Based on this preliminary data, our central hypothesis is that
many VOCs observed in breath are produced by the gut microbiota and thus represent biomarkers of
gut microbial community configuration and function. We will test our central hypothesis through the following
specific aims: (1) Evaluate the extent to which gut microbial communities shape breath VOC profiles; and (2)
Characterize human gut microbes that generate VOCs and demonstrate that microbe-produced VOCs are
present in the breath of gnotobiotic mice. Our investigations will be significant, because we will greatly advance
our fundamental understanding of the gut microbial contribution to breath volatile composition, and we will begin
to identify specific, individual volatile-microbe correlations. Our work will therefore launch a new paradigm
towards novel, non-invasive “breathalyzer” diagnostics to interrogate gut microbial dysbiosis.

## Key facts

- **NIH application ID:** 10171781
- **Project number:** 5R21AI154370-02
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Andrew Leon Kau
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $208,438
- **Award type:** 5
- **Project period:** 2020-06-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10171781

## Citation

> US National Institutes of Health, RePORTER application 10171781, Microbial Origin of Breath Volatile Metabolites (5R21AI154370-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10171781. Licensed CC0.

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