i) Forest crops, for example sweetgum, cultured hybrid poplar, alder and further hard woods.
iii) Sugar crop, for example sugarcane refuse or bagasse.
iii) Herbaceous crops, for example non woody plants.
Human and Animal waste are indirect land crop as of which ehtylene and methane can be formed as retaining fertilizer value of manure. An aquatic crop grows in fresh, sea and brackish waters contain seaweeds, mavine algae and different kelps. There are three type of bioconversion method.
1. Direct combustion, for example wood waste and bagasse.
2. Biochemical conversion.
3. Thermochemical conversion.
Fermentation is break of difficult molecules in natural compounds by the help of ferment for example yeast, enzymes, bacteria and so on. Grains and sugar crops are changed through fermentation into ethanol. Ethanol with gasoline (called as gasohol) can use as an auto fuel.
Biochemical conversion too takes place with two ways that is anaerobic fermentation and digestion. Anaerobic diagestion is bacterial rotting of natural matter (biomass) in nonexistence of air or oxygen to eventually make a gaseous combination of methane and carbon dioxide in irregular volume ratio as 2 : 1. Carbon dioxide created by anaerobic digestion can removed to make synthetic natural gas, as the remain sludge retains it’s nitrogen to make a good fertilizer.
Thermochemical conversion takes place through two ways that is gasification and liquefaction. Gasification is prepared through heating the biomass by limited oxygen to make low heating value gas. The latter can be subjected to liquifaction through converting it into ethanol and methanol.