On the Greek island of Crete, goats spend their summer days idly snacking on dry grass. Then they poop it out, leading to epiphanies for materials engineers like Dr. Alexander Bismarck of the University of Vienna. Bismarck was watching the goats one day when he realized that goat excrement is partially digested plant material — and where there’s plant material, there’s paper.
“Animals eat low-grade biomass containing cellulose, chew it and expose it to enzymes and acid in their stomach, and then produce manure,” Bismarck said in a statement on Wednesday. “Depending on the animal, up to 40 percent of that manure is cellulose, which is then easily accessible.”
In research presented to the American Chemical Society in New Orleans on Wednesday, Bismarck explained how his realization could shake up the paper industry. Move over trees: Bismarck and his team have demonstrated that manure can be used to sustainably make paper.
Cellulose is the raw material that is used to make paper. That means that some animal excrement could be an absolute gold mine of potential paper. And while it may seem like a last resort to make paper from poop, Bismarck says that it actually can offer advantages compared to raw wood. For one, it takes less energy, and less chemical treatment, to process cellulose because an animal’s digestive tract has already done some of the work.
Most importantly, the promise of deriving paper from manure is a big deal from a sustainability standpoint — especially considering that cellulose could be mined from the poop of creatures as big as cows and elephants. All of a sudden, mountains of manure can transform from irksome excrement into a lucrative resource.
To tap into this supply, Bismarck and his team treated the manure with a sodium hydroxide solution and bleached it with sodium hypochloride. This process left them with pulp that could be turned into filters and other paper products.
Bismark is currently working with the paper industry to see what other uses can be found for the poop pulp. If there is any joy in this world, then hopefully they will be able to transmute manure into toilet paper — not just because it would be poetic, but because there might actually be a very dire need for toilet paper in some parts of the world.
Last month, there was a toilet paper shortage in Taiwan, in part due to forest fires in Canada and “production problems” in Brazil. Given rampant deforestation, it’s not inconceivable that paper production will become more costly in the future as people chop down too many trees. If we could switch our raw material for toilet paper from plants to poop, it could go a long way in protecting forests under siege and keeping toilet paper cheap and accessible.
Ah, the circle of life.
Abstract: The interest in cellulose fibres, in particular micro- or nanofibrillated cellulose, utilized in paper and composite materials as alternative to conventional fibre materials, has recently grown significantly. Thereby, particularly in countries without access to large forest areas, an alternative to wood as raw material for natural fibres is highly desirable. In order to promote an environmentally sustainable, widely available and cheap raw material, elephant manure was proposed as potential source. As elephants digest only 30 to 40% of their diet, their manure contains large quantities of fibrous cellulosic material. In addition, the mechanical, acidic and enzymatic pre-treatment during ingestion and digestion initiates break down of the fibres. This makes this animal waste a suitable candidate for the use as precursor for the production of micro- or even nanofibrillated cellulose. Nanocelluloses are commonly prepared by mechanical disintegration of plant material, optionally with chemical pre-treatment, thus requiring a lot of energy and chemicals during the fibrillation process. Therefore, utilizing the elephant as the first-stage bioreactor for the defibrillation of cellulose fibres by mechanical and chemical means would constitute an energy-efficient approach.
We demonstrate that by chemical purification of elephant manure, microfibrillated cellulose with controllable properties can be isolated. The fibrils were characterized regarding their cellulose content and physico-chemical properties in order to optimize the extraction process. Optimized fibrils were initially used for the preparation of papers that were characterized regarding their physico-chemical and mechanical properties and served as reference material. Moreover, the fibrils were further mechanically refined and papers produced from these refined elephant manure nanofibrils that were compared to the non-refined elephant manure papers and cellulose nanopapers.