"Air Meat" is made by microbes using a process known as biomass fermentation. It's produced by California-based startup Air Protein.
A similar process is used to make Solein, a protein-rich powder. The maker, Solar Foods, says it's 100 times more climate friendly than meat.
Mikael Kuitunen/solar foods
You can already buy proteins made from microbes. Quorn is a meat alternative derived from a fungus. Quorn says its "mycoprotein uses 90% less land and water than producing some animal protein sources."
In Quorn, the fungus is mixed with an egg- or potato-based binder to produce meat alternatives including fake mince, sausages and chicken nuggets.
Marmite -- a savory spread popular in the UK -- is another food made from microbes -- in this case, concentrated yeast extract, which is a by-product of beer brewing.
Meat-free proteins are becoming increasingly popular. Impossible Foods has produced a burger containing a genetically modified version of heme -- an iron-containing molecule from soy plants, which gives it a meaty flavor.
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The company debuted its Impossible Pork product in January 2020. This pork substitute is also made with soy protein.
KFC has a vegan burger available in some countries. It is made from Quorn and served with vegan mayonnaise.
Tyson, one of the world's biggest meat producers, has launched a line of chicken-free chicken nugget alternatives, as well as burger patties made with a combination of beef and plants.
Tyson's chicken nuggets are sold under the brand Raised & Rooted. They are made from pea protein, egg white and flaxseed and bamboo fiber.
Beyond Meat makes plant-based meat alternatives. Its burgers have been trialled by McDonald's, and Dunkin' Donuts sells a breakfast sandwich featuring Beyond Meat's meatless sausage.
British bakery chain Greggs introduced a vegan sausage roll in 2019. The filling is made from Quorn.
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The world's largest food company, Nestlé, is adding vegan sausages to its lineup of imitation meat products. Products will include soy-based bratwurst and chorizo-style sausages, as well as pea protein-based sausages that come in habanero cheddar, Asian ginger scallion and chicken apple flavors.
Memphis Meats is among the companies producing meat by growing stem cells in a lab. Innovators including Bill Gates and Richard Branson are investing $17 million in Memphis Meats. Tyson Foods and Cargill have also invested in the company.
Other meat alternatives are not so new. Tofu as been eaten for thousands of years and is made from dried soybeans that are soaked in water, crushed and boiled. Tofu is around 6-8 percent protein.
Tempeh is a traditional Indonesian product made from fermented soy.
Seitan is a meat alternative that originated in Asia, made from gluten, or wheat protein.