The most widely produced biofuel globally is first generation bioethanol from cr
ID: 31703 • Letter: T
Question
The most widely produced biofuel globally is first generation bioethanol from crops like maize (corn) or sugar cane.
a) Besides the costs of buying the feedstock, list the other steps in the process in the manufacture of first generation biofuels that have associated costs.
b) Despite these other costs, the feedstock still makes up a large percentage of the overall costs of the process. How is ethanol from feed wheat made cost effective? And what needs to be done to make this so for straw based ethanol?
Explanation / Answer
a)
Milling
Steaming (to sterilise)
Enzyme hydrolysis (amylase)
Fermentation
Distillation
b) Processing efficiencies may make some differences but the key is in valorising the by-products, so called biorefining. From wheat ethanol production, the spent grains and solubles are combined, dried and sold for animal feed creating as much value as the ethanol. For straw, we need to find ways to add value from the lignin and arabinoxylans that make up 60% of the feedstock by using them to increased the yield of biofuel or by deriving other high value products from these materials