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Veganism, Synthetic Biology and Me

By Polly Wells

Photo credit: Pixabay

“Sorry, are you using this se-?”

“Actually, I’m a vegan.”

We’ve all encountered them. Their pride overspills when Costa calls out their soy flat white and their eyes taint with disgust when they see you with your towering large cup of full-fat cow’s milk hot chocolate.

Okay, you’ve caught me, I order soy flat whites. I don’t give other people bad looks though.

But soy is the barista’s nemesis: the proteins within the soy react poorly with the acidity of the coffee and can often curdle (curdled soy is how you make tofu), and heating the milk to drinking temperature can denature the proteins, leading to further coagulation. [1]

Think I’ll be changing my drinks order to just a black coffee from now on.

Genetically modified organisms could be the saviour that baristas have been desperately craving. Muufri is start-up synthetic biology company that produce cow’s milk, without the cow.

Six proteins: αS1, αS2, β, and κ of the casein family, α-lactalbumin and β-lactoglobulin. There are other proteins within cow’s milk, but these are considered to not contribute to its flavour or behaviour. [2] The bovine genes that yield these six key proteins were identified, isolated, and inserted into the genome of yeast. In a similar way as yeast produces beer, these GM organisms produce milk proteins.

The proteins are then mixed with plant-based oils and fatty acids, a pinch of sugar, a scattering of various minerals, and water. And you have milk “without the moo”.

Whilst Muufri milk has not become commercially available (yet), it would solve the problems baristas face with soy. Looking further than Costa, animal-free milk can also have beneficial impact upon the environment.

Globally, there are approximately 270 million dairy cows. [3] With population rising and westernisation of diets in countries such as China and India, the demand for dairy is high. But dairy farming is highly water intensive, can be damaging to soil, and emit vast quantities of the powerful greenhouse gas, methane.

Water

The global water footprint of dairy farming is over 460 billion cubic metres. [4] Why so much?

A single cow can drink up to 23 gallons of water a day. [4] The food to keep the cow nourished requires water to produce: it takes approximately 6 lb of alfalfa for a cow to produce 1 gallon of milk, and it takes 683 gallons of water to produce those 6 lb of alfalfa, and a cow can produce up to seven gallons of milk in 1 day. [5] Cows also excrete this food; a dairy farm using an automated “flushing” system to clean the facility can use up to 150 gallons of water for 1 cow in just 1 day. [6]

That gives a total of 4,954 gallons of water used per cow, per day.

Soil

Over two-thirds of the world’s agricultural land is used for livestock farming, including dairy cows. Overgrazing and soil impaction from the cow’s hooves can deplete topsoil levels, as well as damage organic matter within the soil, making this a major contributor to soil erosion. [3] In addition, the depletion of soil nutrients is often counteracted by fertilisers, which, in turn, have their own negative environmental effects. Feeding the huge cattle industry also requires a lot of crops, grown on a lot of land. The crops, too, require water and can leave soil void of nutrition.

Greenhouse gases

It is estimated that 4 % of total global anthropogenic greenhouse gas emissions can be attributed to the dairy sector. Approximately 52 % of these harmful gases are methane, and 27 % are nitrous oxide. [7] Methane is 100 times as strong a greenhouse gas than carbon dioxide: the chemical bonds within the molecule absorb UV at such frequencies to induce bond vibration. The vibrating C – H bonds can transmit kinetic energy to neighbouring gas molecules, increasing the overall energy of the system, hence increasing temperature. Nitrous oxide is 3 times stronger than methane (300 times stronger than carbon dioxide) due to its action as a reactive oxygen species (ROS), forming a free radical when exposed to specific wavelengths of UV.



Animal-free milk alternatives have much fewer, and less damaging, environmental impacts than dairy farms: the water footprint of soy is 28 % of that of dairy farms, [8] and the plants absorb greenhouse gases rather than emit them. However, growing the crops has its own problems, such as the depletion of soil nutrients. Yeast, on the other hand, requires even less water, and land, and produces far fewer waste products. The only materials required for yeast to grow are:

  • Yeast extract- yes, Marmite. It’s all the components of a yeast cell, but without the cell wall. This is necessary to provide the biomaterials for the growth and replication of yeast
  • Peptones- amino acids extracted from natural sources. These amino acids are converted into the desired gene products by the yeast, i.e. milk protein
  • Sugar- to provide the energy for cellular respiration [9]

With these 3 simple materials, yeast will happily grow, metabolise, and replicate. The proteins produced will then need to be extracted and isolated from the yeast, but this is achieved easily with a mild alkali treatment followed by boiling in buffer for a couple of minutes [10].

The ease and comparatively low environmental impacts of growing yeast means synthetically designed and genetically modified microorganisms could be the future of eco- and animal-friendly foods. Other synthetically designed organisms are being used to create a range of other vegan products; Clara Foods have produced egg whites without a hen, [11] and Impossible Foods have produced a beef burger made from plant material. [12]

Synthetic biology also has applications outside of the food industry, including therapeutics and pharmaceuticals: these will be discussed in a separate article.

If you are concerned with the environmental impacts of the dairy industry, or the environment on a whole, try veganism. The Great Vegan University Challenge is taking place this February and it is great way to begin your vegan journey. With the field of synthetic biology rapidly expanding, disappointing meat-substitutes could be a thing of the past, and in their place, meat made from modified microorganisms. And no more tofu in my coffee.


References

  1. J. Hartley, The Trouble With Soy. [Online] 2014. [Cited: 21 January 2016.] http://www.fivesenses.com.au/blog/2014/05/28/the-trouble-with-soy.
  2. R. Pandya, Milk Without The Moo. New Scientist. 28 June 2014.
  3. World Wild Life (WWF). Stable Agriculture: Dairy. [Online] [Cited: 21 January 2016.] http://www.worldwildlife.org/industries/dairy.
  4. A. Y. Hoekstra, Animal Frontiers, 2012, 2, 3-8
  5. K. Good, Milk Life? How About Milk Destruction: The Shocking Truth About the Dairy Industry and the Environment. [Online] 2014. [Cited: 21 January 2016.] http://www.onegreenplanet.org/animalsandnature/the-dairy-industry-and-the-environment/.
  6. US Department of Agriculture, Soil Conservation Service. Agricultural Waste Management Field Handbook. 1992, pp. 4-8.
  7. Food and Agriculture Organisation of the United Nations (FAO): Animal Production and Health Division. Greenhouse Gas Emissions from the Dairy Sector: A Life Cycle Assessment. 2010.
  8. E. A. Ertug, M. M. Aldaya and A. Y. Hoekstra, Ecological Indicators, 2012, 18, 393-402.
  9. JoVE Science Education Database. Essentials of Biology 1: yeast, Drosophila and C. elegans. Yeast Maintenance. JoVE, Cambridge, MA, doi: 10.3791/5095 (2016)10.
  10. V. V. Kushnirov, Yeast, 2000, 16, 857-860
  11. Clara Foods. Clara Foods. [Online] 2015. [Cited: 23 January 2016.] http://www.clarafoods.com/.
  12. Impossible Foods. The Impossible Burger. [Online] 2015. [Cited: 23 January 2016.] http://impossiblefoods.com/.


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