Корма из метана - это больше, чем сотрясение воздуха (Methane-based animal feed is more than just hot air)

 13.02.2017 06:14:55

Methane-based animal feed is more than just hot air
Using natural gas to create nutrition for fish and pigs benefits a hungry world

FEBRUARY 1, 2017 by: Maija Palmer
Dusty-looking animal feed pellets that taste "something like Marmite" and contain a protein made out of methane gas could be a key to food security as the world population grows.

The pellets are made using methane-eating bacteria - methanotrophs - that are found naturally in soil and lakes. These are fed methane gas, which makes them grow and multiply into a protein-rich biomass that can be dried and turned into animal feed.

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"It is essentially fermentation [the conversion of sugar into acids, gases or alcohol, mainly by yeast and bacteria] but with a twist," says Alan Shaw, chief executive of Calysta, a US-based company that is one of the pioneers of producing the methane-based protein. "With most fermentation the carbon source is sugar, where as here the source is methane."

Though a simple idea, the pellets are not easy to make. Henrik Busch-Larsen, chief executive of Unibio, a Danish company working on a similar meSthane-based animal feed, says: "It is a difficult reaction to control. You need to get as much methane gas as possible into the liquid that the bacteria are in."

The aim is for the bacteria to reproduce efficiently enough to make the process worthwhile.

The technology has only recently reached the point where it can be commercialised. Calysta opened a plant producing the protein in Teesside in the UK in September 2016, and plans to open a US facility that can produce up to 200,000 tonnes of animal feed a year.

The company is backed by Cargill, one of the world's largest agricultural trading groups. Unibio, meanwhile, opened a factory in Denmark last November and aims to open a larger plant in the Baltic region by the end of 2017.

For now, Calysta is focusing on fish feed, while Unibio's product will be sold to fish, poultry and pig producers. The protein has been approved for fish and animal use by the EU, and farmers have so far been enthusiastic about the product, says Mr Busch-Larsen.

1. Leaves and dead fish fall to the lake floor. These decompose releasing a natural gas that is high in methane (CH4) content

2. The methane is released into the water where it combines with minerals and oxygen

3. The bacteria, Methylococcus capsulatus, consume the methane, minerals and oxygen, so growing in size and number, and becoming rich in protein

4. The fish and other lake animals eat the bacteria as a source of protein

The reason for this interest is economic. Many are keen to find a substitute for traditional fishmeal, which can fluctuate in price between about $1,300 and $2,500 a tonne, making financial planning difficult for farmers. A methane-based feed will be in the middle of that price range, so while it will not be cheap the price should be stable.

There are also broader environmental benefits, the companies say. Production of the protein uses little water and land, making it more sustainable than feeds such as fishmeal or soybeans.

"In Denmark we are importing 1.7m tonnes of soy each year just to feed pigs. Growing that ourselves would take up a third of all available farmland," says Mr Busch-Larsen.

"An increased focus on sustainability is part of the reason there is interest in this product now," he says. "There is a growing awareness that humankind is facing a protein scarcity problem as the population grows."

1. Natural gas, fed into a fermenter, is the key component used to convert Methylococcus capsulatus into highly concentrated protein pellets

2. The fermenter is designed to provide the bacteria with optimal growth conditions, including the addition of methane

3. The bacteria are harvested continuously using a downstream process that removes liquid to increase bacterial biomass. The water is recycled

4. The final stages of the process turn the biomass into easy-to-digest granules that are 73% protein

The UN estimates the world's population will rise to 9.7bn by 2050, and that food production will have to increase by 70 per cent. Consumption of meat is also increasing as people in emerging markets grow richer.

"Only so much wild fish can be taken out of the sea to create fishmeal. Taking fish out of the sea to produce more fish is not sustainable, nor is cutting down more rainforest to grow more soy, " says Josh Silverman, co-founder and chief scientific officer at Calysta. "This product, on the other hand, has no impact on the human food chain - the carbon is coming from outside the current food chain."

An added bonus is that making the protein uses up methane, a greenhouse gas. Environmentalists may be somewhat dismayed, however, that the methane source will be natural gas, at least initially.

Using a fossil fuel for food production will not sit well with some, admits Mr Silverman. "Natural gas is a bridge. It allows us to get this into the market quickly," he says.

Eventually he wants the company to move to using methane gas produced from animal effluent, or decomposing waste. This would make production more sustainable. In due course the protein could create a closed-loop system, with methane from pig or chicken waste being used to create feed that is fed back to the animals.

Taking fish out of the sea to produce more fish is not sustainable, nor is cutting down more rainforest
Josh Silverman
Biomethane is often produced in small quantities and difficult to collect. Finland's VTT Technical Research Centre is running a project to see if the technology could be adapted to individual farms or small areas.

"Finnish dairy farmers are growing aware of the environmental problems with methane production and interested in solutions," says Juha-Pekka Pitkänen, who is leading the VTT study.

His team plans to test small reactors that produce the bacteria at two farms this summer. "The main problem is making the reactors cheap enough and to find ways to get economies of scale," Mr Pitkänen says.

It is possible that one day methane-based protein could be consumed directly by humans. "These kinds of products could end up in human protein bars eventually," Mr Shaw believes.

Both Mr Shaw and Mr Busch-Larsen have tried their own food but neither plans to enter the human market as there could be considerable public aversion. "You would have to modify the process," says Mr Busch-Larsen. "It is not for tomorrow."

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