"Fermentario" ("Fermentative") appeared in 1938. Most of the fermentative substrates are organic molecules. It is an obligate anaerobe with fermentative metabolism. Several potential causes for the decline in fermentative activity have been investigated. These methanogens can often be found in environments containing fermentative organisms. Instead, this process eliminates inhibitory H produced from fermentative growth. They are not spore forming, strictly aerobic and not fermentative. They have a respiratory and fermentative type of metabolism. There are many anaerobic fermentative reactions. This state of fermentative glycolysis is catalyzed by the A form of LDH. Ultrasonication pretreatment has been effective in increasing fermentative bioenergy production from "Scenedesmus oliquus" YSW15. This disproportionation reaction is catalysed by methanogen archaea in their fermentative metabolism. Not all fermentative organisms use substrate-level phosphorylation. Photo fermentative bacteria are able to generate hydrogen from VFAs. As oxygen is not required, fermentative organisms are anaerobic.