Hacker News Reader

Comment by lvs | Hacker News Reader

> If cement manufacturing alone were a country, it would be the third-largest emitter of CO2 on the planet. Since mushrooms are relatively easy to feed, can be grown anywhere, and are appealing to increasingly environmentally aware consumers, we expect to see significant growth in mushroom tech solutions in building materials.

Mushrooms are not plants. They don't photosynthesize and fix carbon dioxide from the air. Growing mushrooms is still carbon positive. It's important to understand that this is an organism that respires, so these generic claims about a carbon benefit need much more analysis to understand whether there is in fact a benefit at scale.

View on HN

By themselves they may not remove carbon from the air but they do sequester carbon by consuming carbon stores and converting them into different products.

You could, in theory, make a wolffia farm (Wolffia being the fastest growing plant on the planet and very carbon hungry to boot) and feed the wolffia to mushrooms to convert them into building, clothing, and packing materials and thus create a cycle of utilitarian carbon sequestration

https://www.cshl.edu/how-to-bury-carbon-let-plants-do-the-di...

https://cleantechnica.com/2013/04/04/mushrooms-could-be-key-...

> they do sequester carbon by consuming carbon stores

They can't sequester any more carbon than was in the feed stock. And when you're trying to sell a biodegradable thing (which I think is laudable), this would have a minimal net effect on carbon for a material that is readily disposed and biodegrades within a few weeks. The benefits of reducing plastic waste, landfill, and pollution are obvious. The carbon benefits are less clear. Paper packaging from pulp waste comes directly from a photosynthetic resource, and may be found to be equivalent materials. So the argument for mushrooms as an intermediate seems like it needs more explanation -- to me anyway. Obviously, a bioplastic that never degrades is a far better carbon sink than a material that degrades readily, but then you are generating waste that must be stored somewhere indefinitely. Not a problem for a building material, but obviously not great for packaging. But I don't see how a building material made from mushrooms could ever sequester more carbon than, you know, wood.

It's about speed. Wolffia can double in size every day whereas the fastest growing woods can take years to double in size.

Also, while Wolffia is human and livestock edible, to make it safe for consumption would require precise control over the growth media to prevent unhealthy buildup of contaminants whereas using it as feed for self-growing building materials, clothing materials, and packaging materials is a viable alternative.

It would require little by way of energy, be a carbon-negative process practically from the start, help supplant a more dangerous industry (plastics and foams) with a safer one, and the waste products would be compostable organics.

Further, Wolffia prefers mildly acidic, highly carbonated water for optimal growth, so you could boost production by percolating carbon-heavy air into the water, and for secondary utility you could also grow fish in the vats to provide additional fertilizer for the Wolffia while also farming a secondary source of income, or failing that you could incorporate these farms into wastewater cleanup plants, allowing them to help provide clean drinking water for cities while also absorbing carbon out of the air, locking that carbon into static pieces, and then growing useful materials from them all in one fell swoop.

So, yeah, wood has its uses and is a great carbon sink, but for sheer quantity and speed Wolffia and mushrooms have it beat.

There is a problem though, and that is getting Wolffia to grow in a farm is a difficult process that we do not have mastered. It can be done but it takes time and skill to get started, and would require maintenance above and beyond traditional farm work, but if that problem were solved then it would be a good thing all around.

Reply on news.ycombinator.com