[cratermoon]

Plants use water, sunlight, and organic chemicals. In plants, protein is made from soil nitrates. Bacteria don't feed the plants, but they can fix nitrogen from the air into the soil. If we really wanted to cut out the middleman, we'd turn the nitrogen we breathe directly into proteins. For now, we have to eat to obtain the essential amino acidd, Histidine; Isoleucine; Leucine; Lysine; Methionine; Phenylalanine; Threonine; Tryptophan; and Valine