Tailored Bioparticles With the Potential to Reduce Ruminant Methane Emissions

Project background

Agriculture contributes between 3 and 4% to the global gross domestic product (GDP). A growing world population dictates an increasing demand on food suppliers and both crop and livestock production indices have been steadily rising. Such an intensification in production comes at the cost of a growing carbon footprint. Agricultural emissions are a recognized contribution to anthropological climate change and emissions continue to grow annually. In particular, meat, wool, and dairy production relies on ruminants which annually produce ∼80,000,000 metric tons of methane, contributing almost 30% of global methane emissions.

Methane reduction strategies require effective, cost-efficient, and non-toxic (environmentally friendly) mechanisms that specifically target rumen methanogens, the microbes that synthesise methane cells without negatively impacting on the microbial plant fiber degradation or on animal production parameters.

Project Strategy

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One such strategy, phage therapy, has been used in biomedical applications since 1920. Phage lysins, enzymes capable of hydrolyzing bacterial peptidoglycan, provide a range of distinct advantages over intact phage and are under development as a priority antibiotic alternative. Emerging evidence demonstrates that lysins of archaeal viruses are similarly capable of hydrolyzing pseudomurein, a cell wall type common to the main methanogen clades in the rumen.

The main rumen methanogen species comprise Methanobrevibacter gottschalkii, Methanobrevibacter thaueri, Methanobrevibacter smithii, and Methanosphaera stadtmanae and, in New Zealand ruminants Methanobacteriales and Methanomassiliicoccales comprise 99.98% of all rumen methanogens.

Functionalised bioparticles comprised of polyhydroxyalkanoates (PHA) hold the promise of combining the advantages of enzyme immobilization while enhancing the technology with directional enzyme display on the bead surface. By displaying lytic enzymes active against the major rumen methanogen species, inhibition of methanogens may lead to a sustainable reduction in ruminant methane emissions without negatively impacting animal productivity.

[1]

(A) Electronmicrograph of PeiR-displaying bioparticles. (B) Artistic rendition of PeiR-single fusion bioparticles. The lytic enzyme PeiR is directionally displayed on the surface of bioparticles formed by the hydrophilic polyhydroxybutyrate core

Results #1

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

The effect of lytic enzyme displaying bioparticles on the growth of rumen methanogens was qualitatively monitored over time using fluorescence microscopy.

Over the course of 4 days, control cells were metabolically active as exhibited by blue-green autofluorescence, typical for viable methanogens (methanogens without bioparticles (‘M1’) and methanogens with inert bioparticles (‘M1 + PhaC’).

In contrast, exposure of methanogens to lytic enzyme bioparticles reduced cell numbers immediately (‘M1 + PhaC-PeiR’). Over time, the number of visible cells remained almost undetectable, indicating that new methanogen cells continued to be susceptible to bioparticle exposure.

Results #2

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Lytic enzyme bioparticles were added to a continuous flow fermenter, mimicking the native rumen environment.

An intricate interplay emerged between the two major rumen methanogen clades, M. ruminantium and M. gottschalkii. Over the course of the rumen simulation, inverse oscillations in relative abundances between these two clades were observed, seemingly associated with the longitudinal modulation in methane emissions (A and C).

Overall, a ~25-30% decrease in total archaeal cell numbers was observed (B).

[3]

Results #3

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Lytic enzyme bioparticles mediated up to 15% reduction in emissions against non-functionalized bioparticle controls over 11 days of continuous fermentation in the rumen simulation.

[4]

Future Perspectives and Opportunities

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Targeting other methanogens could be mediated through the deployment of bioparticles displaying different bacteriophage lytic enzymes, all with their own host specificity and activity, opening the door for a plethora of functionalized bioparticle, tailored toward different microbes, feeding regimes, and environmental drivers.

[5]

Global emissions by source. Relative contribution of main sources of emissions from global livestock supply chains.

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Tailored Bioparticles With the Potential to Reduce Ruminant Methane Emissions

Project background

Agriculture contributes between 3 and 4% to the global gross domestic product (GDP). A growing world population dictates an increasing demand on food suppliers and both crop and livestock production indices have been steadily rising. Such an intensification in production comes at the cost of a growing carbon footprint. Agricultural emissions are a recognized contribution to anthropological climate change and emissions continue to grow annually. In particular, meat, wool, and dairy production relies on ruminants which annually produce ∼80,000,000 metric tons of methane, contributing almost 30% of global methane emissions.

Methane reduction strategies require effective, cost-efficient, and non-toxic (environmentally friendly) mechanisms that specifically target rumen methanogens, the microbes that synthesise methane cells without negatively impacting on the microbial plant fiber degradation or on animal production parameters.

Project Strategy

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

One such strategy, phage therapy, has been used in biomedical applications since 1920. Phage lysins, enzymes capable of hydrolyzing bacterial peptidoglycan, provide a range of distinct advantages over intact phage and are under development as a priority antibiotic alternative. Emerging evidence demonstrates that lysins of archaeal viruses are similarly capable of hydrolyzing pseudomurein, a cell wall type common to the main methanogen clades in the rumen.

The main rumen methanogen species comprise Methanobrevibacter gottschalkii, Methanobrevibacter thaueri, Methanobrevibacter smithii, and Methanosphaera stadtmanae and, in New Zealand ruminants Methanobacteriales and Methanomassiliicoccales comprise 99.98% of all rumen methanogens.

Functionalised bioparticles comprised of polyhydroxyalkanoates (PHA) hold the promise of combining the advantages of enzyme immobilization while enhancing the technology with directional enzyme display on the bead surface. By displaying lytic enzymes active against the major rumen methanogen species, inhibition of methanogens may lead to a sustainable reduction in ruminant methane emissions without negatively impacting animal productivity.

[1]

(A) Electronmicrograph of PeiR-displaying bioparticles. (B) Artistic rendition of PeiR-single fusion bioparticles. The lytic enzyme PeiR is directionally displayed on the surface of bioparticles formed by the hydrophilic polyhydroxybutyrate core

Results #1

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

The effect of lytic enzyme displaying bioparticles on the growth of rumen methanogens was qualitatively monitored over time using fluorescence microscopy.

Over the course of 4 days, control cells were metabolically active as exhibited by blue-green autofluorescence, typical for viable methanogens (methanogens without bioparticles (‘M1’) and methanogens with inert bioparticles (‘M1 + PhaC’).

In contrast, exposure of methanogens to lytic enzyme bioparticles reduced cell numbers immediately (‘M1 + PhaC-PeiR’). Over time, the number of visible cells remained almost undetectable, indicating that new methanogen cells continued to be susceptible to bioparticle exposure.

Results #2

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Lytic enzyme bioparticles were added to a continuous flow fermenter, mimicking the native rumen environment.

An intricate interplay emerged between the two major rumen methanogen clades, M. ruminantium and M. gottschalkii. Over the course of the rumen simulation, inverse oscillations in relative abundances between these two clades were observed, seemingly associated with the longitudinal modulation in methane emissions (A and C).

Overall, a ~25-30% decrease in total archaeal cell numbers was observed (B).

[3]

Results #3

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Lytic enzyme bioparticles mediated up to 15% reduction in emissions against non-functionalized bioparticle controls over 11 days of continuous fermentation in the rumen simulation.

[4]

Future Perspectives and Opportunities

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Targeting other methanogens could be mediated through the deployment of bioparticles displaying different bacteriophage lytic enzymes, all with their own host specificity and activity, opening the door for a plethora of functionalized bioparticle, tailored toward different microbes, feeding regimes, and environmental drivers.

[5]

Global emissions by source. Relative contribution of main sources of emissions from global livestock supply chains.

Have a question about the programme?

Get in contact with us below!
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.