Decarbonisation doesn’t just come from paring back
industrial activities such as the burning of fossil fuels. In recent years
there has been a significant increase in the scrutiny applied to agriculture,
as more and more research shows that this sector is responsible for significant
However, reducing emissions is of little use if people can
no longer be fed, and so much innovation has been directed at making
agriculture more efficient and less carbon intensive. One of the areas being
most heavily targeted has been meat production, as research has shown this to
be a major source of emissions. However, the protein that meat provides is a
necessary part of the human diet – the only way of obtaining amino acids for
the body to produce its own proteins – and so this particular source of food
cannot just be cast aside in the name of carbon reductions, alternatives must
be found. So what are these alternatives and where do they fit into the
The Environmental Impact of Meat
Any ecologist will tell you that the more steps there are in
the food chain, the lesser the energy efficiency, but this does not translate
as well into emissions. The primary sources of emissions associated with meat
production come from the land-use change associated with pasturing, and from
the animals themselves. Cows are ruminant animals, which means they produce
large quantities of methane while processing their own food, which is then
released to the atmosphere. Methane has a stronger greenhouse effect than CO2,
resulting in 25 times more warming over the same time period than for an
equivalent amount of CO2. Large beef herds are therefore significant
sources of methane and thus have dramatic emissions profiles. Per kilogram on
the plate, beef has an emissions profile over seven times greater than palm
oil, with the latter already being a significant source of environmental
It is these environmental concerns, along with increasing
awareness of animal welfare and the need for more land-efficient food
production in the advent of a rising global population, that has spurred the
search for alternative protein sources. Some of these are well known and
already in wide circulation – beans, pulses, and fungi such as Quorn being the
obvious examples – but the bioeconomy has a few potential avenues to explore
that may bring benefits beyond provision of protein for consumption.
Insects: Smaller animals, bigger prospects
From a pure energy-efficiency perspective, eating meat from
non-endothermic animals such as insects and fish is more efficient than eating
meat from endothermic animals such as mammals and birds, since the latter
expend energy in heating their bodies. Insects have been eaten by humans for
millennia, but in western cultures it is still seen as a taboo. Nonetheless, companies like Eat Grub in the UK attempting to market them.
The environmental arguments for eating insects are
palpable: due to the aforementioned energy efficiency, they require less land,
feed, and water to rear than traditional meat animals, and display much faster
growth, making rearing less time-intensive too. Legislations that cover food
animals also apply to insects if said insects are for human consumption, and so
consumers can be assured of the same legal protections.
But perhaps the most interesting aspect of insects as a food
source comes from how they can be reared. Organic waste is always an area of
interest for the bioeconomy, as it forms a useful feedstock for many biobased
processes. The bioeconomy offers a variety of novel methods of processing
organic waste, and rearing insects for food may be one of these. Insects can be
reared on organic waste, as is being trialled by the Scalibur project in the
EU, and their larvae then processed to produce protein for use as a food
ingredient. Widespread use of this would require regulatory approval by
relevant food safety authorities, as it essentially amounts to the production
of food from waste, but the signs are promising, as insect protein products are
already on the market as pet foods.
However, insect proteins come with very obvious barriers to
their widespread acceptance: concerns about animal welfare are not diminished
by rearing insects for food, not to mention consumer revulsion must be
overcome, particularly in western countries where insects do not traditionally
form part of the diet.
Meat Without Animals at All
Of course, were it possible to continue to eat meat without
any of the environmental downsides, this would be the most amenable solution
for meat eaters. As cell-culturing process continue to develop, this is
becoming a more realistic, if expensive, option. Companies such as California’s
Just Meat and Singapore’s Shiok are developing meat products made from animal
cells cultured in labs. Meat is, of course, made from a combination of many
different kinds of cell, and so the challenge comes not from culturing individual
cell types, but from obtaining a cellular structure that behaves the same way
when cooked and eaten.
Currently, this meat produced in this way is not approved by
any food safety authorities and thus remains absent from the market. When it
does eventually land on the market, it will initially be very expensive to the
consumer, but could offer a meat alternative without worries about animal
welfare or carbon emissions. However, the necessity for meat of this kind to be
grown in a lab may raise questions about accessibility, particularly for rural
communities and for less economically developed nations.
Protein from microbes, a familiar process
Obviously, microbes are already a significant presence in
food: from the yeasts used in baking and brewing to the moulds used in
cheesemaking, but these are far from microbes’ only uses in food. The
increasing popularity of Quorn has demonstrated the viability of using microbes
as a protein source. Quorn is made from microfungi grown in fermenters and used
as ingredient in meat-substitute foods.
But it is not just fungi that can be sources of microbial
protein. There has been increasing interest in algal protein, as algae have
been found to have relatively high protein content for plants. Algae can be
genetically modified to produce chemicals that can then be extracted from the
algae themselves – this is the same premise behind algal biofuels – and this
also applies to proteins. Algae have already been trialled as protein sources
for aquaculture, and the UK saw its first algal-protein drink come onto the
market last year.
However, growing algae for food and feed comes with the same
issues that have been found by those looking to grow algae for biofuels: scale.
Algae grow very well in controlled lab conditions, but scaling up the process
to a level that can support commercial operation is challenging, and for a
sector like food that requires huge yields, this will be an interesting barrier
for algal proteins to overcome.
microbes and the bioeconomy have a relationship beyond cultivation for food,
and this could be key in a potential protein avenue being explored by US company Calysta and Danish
Biogas is already utilised as a fuel for transport and energy generation, and
is one of the bioeconomy’s most well-known end-products, but as the global
paradigm shifts in the future to non-combustible renewables such as solar and
wind power, biogas may still have a role to play.
Unibio has developed a process by which methanotrophic
bacteria (bacteria that consume methane as an energy source) can be “fed”
biogas, and their resulting biomass is used a protein source. This process
already occurs naturally in aquatic ecosystems but is difficult to control
therein. By utilisng fermentation technology, biogas that is produced from
waste processing can ultimately become a protein source in food. Like the
insects above, this shows the potential for a bioeconomy process with a twofold
benefit of waste management and food production.
Maximising plant food efficiency
Of course, it is not only animals and microbes that can be
sources of protein: plant matter contains protein too, but usually at lower
levels, hence the need for animals to supplement their diets with meats or
roots. One protein, however, that is present across all plants is Rubisco, a
key enzyme in the process of photosynthesis. This protein has a highly
nutritious amino acid profile, and is digestible by humans, but is rarely eaten
due to its presence in plant leaves, which are not usually the part of the
plant consumed by humans. The Green Protein project is looking to make use of
this potentially valuable protein. By processing the by-products from vegetable
cultivation, additional value (both nutritional and economic) can be obtained.
The project has found that if Rubisco can be extracted,
sugar beet leaves can produce as much protein per hectare as soybeans – already
a widespread source of plant protein – which can be coupled with sugar beet’s
existing uses as a food and biofuel crop to both minimise waste and maximise
yield, which should be the goal of any agricultural system. The project aims to
have a product on the market by 2023.
What barriers remain?
Though research is showing that consumers are increasingly
likely to make more environmentally conscious decisions, there still remain
some barriers to alternative protein sources becoming widespread. The most
prominent of these is consumer acceptance: consumers that are accustomed to
eating meat regularly will need to alter their eating habits and may be
reluctant to do so without significant marketing effort. The other main barrier
is a legal one: novel foodstuffs and food production processes, particularly in
the EU, must meet strict regulations in order to demonstrate suitability for
human consumption, and must be approved by the relevant authority before being
placed on the market.
Despite these barriers, the problems of both agriculture’s
environmental footprint and the need for more efficient food production are not
going away, and alternative protein sources are going to be at the forefront of
those discussions for a long time yet.