Microbiome metabolism: Scientists reveal how gut bacteria break down complex carbohydrates

An international team of researchers have uncovered the cellular mechanisms that allow bacteria a single group of bacteria found in our microbiota to break down complex sugars and fibres.

The team of scientists from the UK, Sweden, Canada and the US, have begun to uncover how our gut bacteria metabolise the complex dietary carbohydrates found in fruits and vegetables by revealing the 'genetic machinery' that allow gut bacteria called Bacteroidetes to digest complex sugars known as xyloglucans.

Writing in Nature, the team of researchers behind the study suggested that the findings begin to illuminate the specialised roles that are played by key members of our vast microbiome, and could inform the development of further research and development aimed at improving human health via the microbiota.

"While they are vital to our diet, the long chains of natural polymeric carbohydrates that make up dietary fibre are impossible for humans to digest without the aid of our resident bacteria," explained lead researcher Professor Harry Brumer from the University of British Columbia. "This newly discovered sequence of genes enables Bacteroides ovatus to chop up xyloglucan, a major type of dietary fibre found in many vegetables – from lettuce leaves to tomato fruits. 

"B. ovatus and its complex system of enzymes provide a crucial part of our digestive toolkit."

Indeed, understanding how these bacteria digest complex carbohydrates can informs studies on a wide range of nutritional issues including prebiotics and probiotics, according to Professor Gideon Davies - who led the UK arm of the research.

"Our findings reveal that the metabolism of even highly abundant components of dietary fibre may be mediated by niche species, which has immediate fundamental and practical implications for gut symbiont population ecology in the context of human diet, nutrition and health," wrote the research team.

"The possible implications for commerce and industry extend beyond the realm of human nutrition, however," added Davies. "The study of how enzymes break down plant matter is also of direct relevance to the development of processes for environmentally-friendly energy solutions such as biofuels."

Probiota 2014

Invested in pre- and probiotics? Probiota 2014 will explore the prebiotic-probiotic scientific frontier, its evolution and commercial application in food, nutraceuticals, pharmaceuticals and cosmetics across the globe.

The 2-day, 2-stream event – formerly Probiotech and Microbiota - will be held in Amsterdam on February 4-5 this year. Will you be joining your peers there?

To know more click here.

Source: Nature

Published online ahead of print, doi: 10.1038/nature12907

"A discrete genetic locus confers xyloglucan metabolism in select human gut Bacteroidetes"

Authors: Johan Larsbrink, Theresa E. Rogers et al