Identification of Gut Microbiome Composition Responsible for Gas Production

Authors

Erasme Mutuyemungu, University of Nebraska-LincolnFollow

First Advisor

Dr. Devin Rose

Date of this Version

11-2022

Document Type

Article

Citation

Mutuyemungu,E. (2022). Identification of Gut Microbiome Composition Responsible for Gas Production. (Master Thesis, University of Nebraska- Lincoln, Lincoln, NE, United States).

Comments

A THESIS Presented to the Faculty of The Graduate College of the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Food Science and Technology, Under the Supervision of Professor Devin J. Rose.

Lincoln, Nebraska: November 2022

Copyright © 2022 Erasme Mutuyemungu

Abstract

Gas production remains a significant barrier to increasing intake of dietary fiber-containing foods for many consumers. Therefore, this thesis is comprised of two studies focusing on the role of the gut microbiome in contributing to gas production during fermentation of dietary components. Previous studies have reported significant correlations between Megasphaera elsdenii and gas production during fermentation of pulses. Therefore, the objective of the first study was to determine the role of M. elsdenii in gas production by the microbiome during fermentation of foods commonly associated with gas production. Human fecal microbiomes were separated based on the presence (Me+) or absence (Me-) of M. elsdenii. After 48 of fermentation, Me+ microbiomes produced significantly more gas than the Me− microbiomes. Furthermore, Me+ microbiomes were more butyrogenic than Me- microbiomes, while Me- microbiomes were more acetogenic and propiogenic. This study suggested that M. elsdenii may be responsible for high gas production during consumption of flatulogenic foods. In the second study, raffinose, an oligosaccharide found in pulses and implicated in gas production, was used as a substrate for in vitro fermentation. The objective of this study was to determine the relationship between raffinose utilization and gas production and identify microbial features that were responsible for gas production during fermentation of raffinose. Unexpectedly, raffinose utilization was negatively correlated with gas production. Raffinose utilization was also positively correlated with acetate production, while gas production was positively correlated with butyrate production. Taxa from Bifidobacterium and Blautia were associated with raffinose degradation and acetate production. Several taxa from Megasphaera, Anaerostipes, Faecalibacterium, and Collinsela, were associated with gas and butyrate production. This study suggested that gas production was not produced directly from the metabolism of raffinose, but rather through cross-feeding between raffinose-degrading, acetate-producing bacteria and acetate-utilizing, butyrate-producing bacteria. Overall, this research has revealed substantial variation in gas production among microbiomes and identified commensal members of the microbiome and cross-feeding pathways that contribute to elevated gas production by the microbiome. These findings will be important in the development of strategies to reduce undesirable gas production during consumption of flatulogenic foods.

Advisor: Devin J. Rose