The low cost substrates proposed by the initiatives include agricultural residues (corn stover, wheat straw, barley straw, rice straw, sweet sorghum bagasse, and sugar cane bagasse), process coproducts (rice hulls, wheat bran, corn fiber, and glycerol), and energy crops (switchgrass, miscanthus, alfalfa, reed canary grass, and Napier grass) [6–8].