4.7 Article

Effect of Freezing on Gut Microbiota Composition and Functionality for In Vitro Fermentation Experiments

Journal

NUTRIENTS
Volume 13, Issue 7, Pages -

Publisher

MDPI
DOI: 10.3390/nu13072207

Keywords

gut microbiota; freezing; storage; foods; bioactive compounds

Funding

  1. Plan propio de Investigacion y Transferencia of the University of Granada under the program Intensificacion de la Investigacion, modalidad B
  2. Plan propio de Investigacion y Transferencia of the University of Granada under the program Perfeccionamiento de Doctores
  3. European Research Commission (Research Executive Agency) under the research project Stance4Health [816303]

Ask authors/readers for more resources

The freezing of fecal material does not significantly alter the functionality of the microbial communities, as potential functionality remains preserved due to functional redundancy. Though the microbial community structure may differ slightly between fresh and frozen samples, the variation introduced by freezing is minimal compared to the variation among individuals. The most affected genus by freezing is Bacteroides, a fiber degrading bacteria.
The gut microbiota has a profound effect on human health and is modulated by food and bioactive compounds. To study such interaction, in vitro batch fermentations are performed with fecal material, and some experimental designs may require that such fermentations be performed with previously frozen stools. Although it is known that freezing fecal material does not alter the composition of the microbial community in 16S rRNA gene amplicon and metagenomic sequencing studies, it is not known whether the microbial community in frozen samples could still be used for in vitro fermentations. To explore this, we undertook a pilot study in which in vitro fermentations were performed with fecal material from celiac, cow's milk allergic, obese, or lean children that was frozen (or not) with 20% glycerol. Before fermentation, the fecal material was incubated in a nutritious medium for 6 days, with the aim of giving the microbial community time to recover from the effects of freezing. An aliquot was taken daily from the stabilization vessel and used for the in vitro batch fermentation of lentils. The microbial community structure was significantly different between fresh and frozen samples, but the variation introduced by freezing a sample was always smaller than the variation among individuals, both before and after fermentation. Moreover, the potential functionality (as determined in silico by a genome-scaled metabolic reconstruction) did not differ significantly, possibly due to functional redundancy. The most affected genus was Bacteroides, a fiber degrader. In conclusion, if frozen fecal material is to be used for in vitro fermentation purposes, our preliminary analyses indicate that the functionality of microbial communities can be preserved after stabilization.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available