Biofuels Flashcards
what does electricity split water into
oxygen and hydrogen
what do the bacterium use as an energy source, and for what
hydrogen, to take in Co2 and convert it to a biofuel
what are the 4 types of fuels
alcohols - bioethanol and biobutanol
vegetable oils and biodiesel
biogas
biohydrogen
what are the two main production strategies
grow crops high in starch
grow crops high in oils
an example of crops high in starch and how they are used
corn, maize - high in sugar - yeast fermentation - ethanol
examples of crops with high amounts of oil and how it is used
soybean, algae - chemically processed into biodiesel - can be burned directly in diesel engine
what are the problems with using corn/sugar cane
more energy in than out, low yield, competes for crop land
what are the problems with rapeseed oil/ biodiesel
compete for crop land, low yield, reduces diversity in cleared areas
problems with biogas
not concentrated enough, not enough demand
what are second generation biofuels made from
biomass - living and dead biological material
what are cellulosic biofuels and what is cellulose
wood/grasses - the non edible parts of plants
complex carb, supports most plant structures, most abundant naturally occurring molecule
How are cellulosic biofuels made
enzymes used to break down cellulose - sugar - microbes ferment sugars to ethanol, then purified
what are 3rd generation biofuels
biofuel carbon derived from light and Co2
Co2 produced from powerstations and industrial plants used to feed the process - biofixation of Co2
3 benefits of bioethanol
high oxygen content
less toxic
uses renewable energy
3 disadvantages of bioethanol
highly corrosive
food vs fuel debate
higher production costs
what is biobutanol
4 carbon alcohol produced by the fermentation of biomass
3 benefits of biobutanol
higher energy content, less corrosive, can be blended with petrol at higher concentration
2 disadvantages of biobutanol
higher production costs
low yield
what bacterium produces a high ethanol yield, has a higher rate of sugar uptake, and a higher ethanol tolerance
Zymomonas mobilis - causes cider sickness and the spoiling of beer
describe this bacterium
rodshaped, gram -ive non-sporulating, facultative anaerobic
what is clostridia
a bacteria, oxygen is toxic to them - they lack aerobic respiration, gram +ive, wide spread in soil
what is ABE fermentation
Acetone Butanol Ethanol fermentation
most common way to produce biobutanol
what differs about the sugars bacteria use vs yeast
bacteria use pentose sugars, yeast don’t
if you ferment a bushel of corn, which method of fermentation would produce the highest concentration of ethanol
yeast fermentation, not ABE
why is butanol superior to ethanol
low product yield vs solvent toxicity - waste - acetone
substrate costs - sugar and starch competition with food
costs of downstream processing - distillation expensive
what is CBP
consolidated bioprocess
organism degrades lignocellulose and ferments the sugar released into fuel
what is the name of gas eating/carbon fixing bacteria
clostridium
what is the pathway called that the carbon fixing bacteria use and what do they produce from it
wood-ljungdahl pathway
acetyl-CoA
what are homoacetogenic bacteria and what do they do
acetogens - anaerobic microos that make Acetate from carbon units in their energy metabolism - they can have Co2 as their sole energy source
what did lanzatech do
made a fermentation process that used industrial waste gas as sole energy and carbon source - completely outside of the food chain
what is in synthetic gas
hydrogen, carbon monoxide, carbon dioxide
2 problems with acetate production
toxic at low concentrations
takes away from ethanol production
what is the future for biofuels
using cellulosic biomass
what are the challenges in cellulosic biofuel production
sustainable feedstock availability
the cost of biomass deconstruction
construction of better more efficient biofuel pathways
