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at AusBiotech’s International BioFest
regarding coal seam gas extraction, the comparison
to coal mining is stark. When coal is mined, the
methane incumbent in the seam is released into
the atmosphere. It’s a potent greenhouse gas and
we release it without extracting energy from it; it’s
Manefield equates coal mining with lying under a
barrique with the tap open, while coal seam gas
extraction is seen as sipping at a mature red from the
Barossa Valley. The former is an environmental disaster
on a planetary scale. The latter is a legitimate play into
the future, not just in the transition to hydro-electric,
wind, solar, geothermal and tidal energy-harvesting
technologies. Gas extraction from coal seams and oil
shale is the pace at which we should be consuming
fossil fuels. This is the approach required to make these
ancient resources last for tens of thousands of years.
But the discovery by Manefield and Beckmann is
equally applicable to gas extraction from renewable
resources that have traditionally not been exploited.
Food and agricultural waste, for example, mostly ends
up in landfill where it is digested, and the methane
produced is ultimately released into the atmosphere
without exploitation. Manefield’s team has shown that
application of their chemical amendment can increase
methane production from food waste tenfold. That’s
like turning one dollar’s worth of gas into $10 of gas.
So, what is this seemingly magical amendment?
During the course of the research, Manefield started
to view communities of different species of microbes
as an electrical circuit board, with electron transfer
reactions (equating to electrical current) as the
foundation of their energy harvesting. Manefield then
realised that if the electrical network could be short-
circuited, it should be possible to channel electrons
towards the methane producers. The chemical
amendment does just this, but through an entirely
The chemical known as ‘neutral red’ is a synthetic
compound invented more than a century ago and used
variously as a textile dye, and more recently in bespoke
applications as a histological stain and pH indicator.
It has been around for a long time, and is well known
for its ability to pick up electrons from one source and
deliver them elsewhere. Such compounds are referred
to as ‘electron shuttles’. They catalyse electron transfer;
they are not consumed. The fact that neutral red has
a crystalline form was unknown until Manefield and
Beckmann discovered the fact, and that the crystalline
form acts like an electron sponge that vends electrons
exclusively to methane-producing microbes.
Never content to leave a discovery in the ivory towers
of university laboratories, Manefield has pushed hard to
conduct field trials of the newly developed technology.
Since 2013, trials have been conducted at the historically
significant Lithgow State Coal Mine in the Western Coal
Fields of New South Wales, with resounding success. A
teaspoon of neutral red was added to wells drilled for
purpose 80 metres below ground into a three-metre-
thick coal seam. Within a week, neutral red had taken
on its crystalline form in the coal seam–associated
groundwater, and over the course of a year, increased
methane yield five- to tenfold.
The discovery is protected by an Australian patent
filed by University of New South Wales’s NewSouth
Innovations and financed by Biogas Energy Ltd, and
was recently published in the esteemed Royal Society
of Chemistry journal Energy & Environmental Science.
It was picked up by science journalists internationally,
and has generated a flood of interest from
professionals in the global biogas industry seeking
improved returns on their infrastructure investments as
government subsidies are wound back.
While there are important technological advances
to be made in translating this discovery to biogas
reactors treating renewable feedstocks, it is clear
that the discovery will have a major impact on biogas
production in the future. Ongoing research and
commercialisation activities are funded through an
Australia-India Strategic Research Fund grant with
industry partners Biogas Energy, Santos and the Indian-
state-owned Oil and Natural Gas Corporation.
Mike Manefield will be speaking at
the 17th International Biotechnology
Symposium 2016 (IBS 2016).
Enhanced biogas production using neutral red crystals (red) in association
with microorganisms (green) and coal particles (black) under fluorescence
microscopy (Image courtesy Dr Sabrina Beckmann)
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