Kangaroo and reindeer research may help reduce greenhouse gas emissions

Understanding how gut bacteria in animals affect methane emissions is important for agriculture.

Kangaroo and reindeer research may help reduce greenhouse gas emissions

An Australian study published in Science provides additional insight into how the gut bacteria in wallabies are implicated in lower methane emissions compared to ruminant livestock.

Taking this a step further post-doctoral researcher Phil Pope, first author of the Science paper and now working at the Norwegian University of Life Sciences (UMB), is studying the gut bacteria of Norwegian reindeer to find out more about how biomass is degraded in their gut.

Understanding these processes is hoped to lead to lower methane emissions from livestock and yield novel enzymes for improved bio energy production from non-food biomass.

"About 10 per cent of the digestible energy in cows and sheep is converted to methane, while Tammar wallabies were shown to produce about one-fifth that amount from similar diets. This makes wallabies and their gut bacteria interesting, when trying to find ways of reducing greenhouse gas emissions from livestock," Phil Pope said.

Pope's wallaby research was carried out while he was employed by Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) with Professor Mark Morrison and a number of partners in the USA, Germany and Australia.

Discovery of a new bacterium
Using a new and technologically advanced computational method combined with traditional culture methods, Pope detected and isolated a new bacterium affiliated with the Succinivibrionaceae from the wallaby gut.

The metabolic properties of the bacterium suggest it may be part of the reason why wallabies produce less methane than ruminants. In ruminants, carbon dioxide and hydrogen are common byproducts of fermentation, which are converted by other microbes into methane. However, the new bacterium found in the wallaby gut instead produces succinate, acetate and formate, while also using carbon dioxide.

“I think these differences "downunder” have provided us some new insights into marsupial nutrition, as well as future opportunities that could redirect rumen fermentation and reduce methane emissions from livestock,” Pope said.

Phil Pope
Phil Pope Photo: Hkon Sparre

Further research on Norwegian reindeer
Analysing how gut bacteria degrade plant biomass and finding better enzymes for biomass conversion may also improve bio energy production.

Enzymes are needed to convert biomass such as hard wood and straw to sugar which then can be fermented to ethanol or biomaterials. Therefore, researchers all over the world are looking for enzyme systems which can accomplish this difficult task.

UMB researchers have previously made major contributions to this field, including the discovery of a completely new class of enzymes that improve the efficiency of enzymatic biomass conversion. This discovery was published by Gustav Vaaje-Kolstad, Vincent Eijsink and co-workers in Science last year.

Phil Pope is now teaming up with the Eijsink group to study gut bacteria and their enzymes in reindeer at Svalbard. Svalbard reindeer are interesting in a bio energy perspective, because of their unique diet.

"They often have to get by on very little food and need to make the most of what they eat. Their diet in winter mainly consists of arctic shrubs, which are not easily degradable. We therefore anticipate that reindeer gut bacteria have very efficient enzymes which convert biomass into energy and nutrients. We are now looking to identify bacteria and enzymes in the reindeer gut and for the first time we will have a unique opportunity to compare the microbiology of animals living in different environments and under very different conditions," Pope said.

This work is in collaboration with Monica Sundset, an expert on reindeer physiology at the University of Tromsø, and several international partners, including his colleagues from CSIRO Livestock Industries in Brisbane and Professor Alice McHardy, from the Max Planck Institute for Informatics in Germany.

Strengthening Norwegian bio energy research
In 2010, Phil Pope was awarded a Marie Curie fellowship to work at UMB and he is now part of the University's excellent bio energy and enzyme research group. His top expertise in the field of metagenomics, bioinformatics and enzyme bioprospecting is now being combined with expertise in advanced enzyme characterization, as well as process development for biomass conversion.

"Bringing these two research fields together is very fortunate for both parties. We are pleased to attract researchers of Phil Pope's calibre. Pope's work yields interesting bacteria and enzymes and provides a unique opportunity for targeted bioprospecting. At UMB we can take this to both a deeper and an applied level in our bioenergy, biorefining and enzyme development projects. Eventually this will lead to better use of natural resources,"  says Vincent Eijsink, Professor and group leader at the Department of Chemistry, Biotechnology and Food Science at UMB.

Published 2. September 2014 - 10:20 - Updated 23. May 2017 - 19:39