Algae and Biofuels
alternative to the alternative - algal biofuels
- Algae biofuels - young founding - Is producing hydrocarbon-like product without too much change to infrastructure that can enter cars and engines well - Incredibly expensive - Much more microbial
photobioreactors
- Bioreactors that incorporate a light source for phototroph growth - Have CO2 bubbled in to allow autotrophy - Prevent water evapoartion - Provide nutrients - algae need a lot of nitrogen and phosphorous - Prevent CONTAMINATION (due to closed system) - Flow through the containers (end is dense and full of molecules we want to collect)
whats algae
- Eukaryotes from various supergroups - Photosynthetic organisms - Autotrophs..... or a mix of auto/hetero - Single-celled, colonial, sometimes multi-cellular - Botryococcus braunii colonial algae - Found naturally, grows in colonies - Phototrophic - Produces Triterpenes >>Hydrocarbons >>C30-36 >>Can be up to 30 - 40 % dry weight >>Some strains reported at >80 % cell mass >>Excretes hydrocarbons easy to isolate - Easy to grow in culture - Grown in photobioreactors
alternative energy
- Not derived from drilled petrochemicals - Stop taking C from C sinks, and have it coming from the atmosphere (don't want influx of C coming into atmosphere) - Includes ethanol, biodiesel from vegetable oil, algal biofuel - Ethanol is currently a focus in the industry - Ethanol biofuel produced from fermentation of plant material (i.e. corn, sugar cane, sugar beet, etc) Raises two problems - energy and ethics
raceway type pond systems
- Open to the environment -> susceptible to contamination - Can not control temperature or light - Cheap! - Large production capacity to cost ratio - Possible to exploit different growth conditions >>Salt content - Huge scale - Put in a very warm area - Lots of light to feed algae - Put in desert so not using agricultural land
biorefinery concept
- Renewable biomass feedstock put in - Microbial activities act on feedstock - Useful materials can be harvested out - used to form biofuels
biofuels - ethanol production
- Yeast can be used to ferment sugars to produce 2-carbon ethanol. - Ethanol can be used in internal combustion engines with little modification - Corn, corn husks, add yeasts and allow to ferment - heated so ethanol is heated off and collect it as fuel commercial scaling expensive - Growing corn takes water, and fuel to work land, good soil, and people good use of resources - Some lignin/cellulose feedstocks are difficult to breakdown. - These feedstocks are usually waste products, so environmentally friendly and value added...if cost is lowered
advantages of algal biofuel
- can grow in freshwater, saltwater, or even wastewater! - needs large area, but does not have to be farm land (deserts? oceans?) - potential for water recycling - can require less energy to maintain (less working of land) - Carbon neutral (fixed C is released with hydrocarbon combustion) - leftover biomass is value-added product! can be fermented to ethanol - Doesn't need to be heated or cooled so low energy - Carbon coming from atmosphere wihtout too much energy cost - Sustainable fuel - Carbon-neutral fuel
ethical dilemma
- growing corn (or other crops) for biofuel also... >>>Requires fresh water & fertilizer (and lots of it) >>>Uses farmable land (often high quality and lots of it) >>>Removes crops / displaces lands from the food supply - The increase in corn ethanol production in the US, canola biofuel in Canada, etc. has contributed to significantly higher food prices worldwide - Not tremendous deal here but in poor countries where you stop growing food to get cheaper gas, isn't good
alternative energy - energy dilemma
- growing corn (or other crops) is more readily incorporated into the ethanol "pipeline" - BUT farming requires energy working the land - conversion from crop to glucose ...reduces the amount of energy gained from the production of ethanol BEFORE - not efficient in getting ethanol so net negative in energy (biofuel process not worth it) NOW: - gaining energy so worth it (in developed countries) - CO2 produced from ethanol combustion is coming from the atmosphere (via the C cycle) rather than from C sinks (i.e. petroleum from the ground!) - Closer to a Carbon neutral energy source
difficulties of large-scale algaculture
- monocultures hard to maintain - need algae that produce high yield of hydrocarbons, resistant to the conditions of industrial scale, able to somehow deal with contamination - Synthetic algae / genetically-modified algae >>millions of genes discovered during ocean expedition >>may be able to design the perfect biofuel algae >>may increase yield 10/100 x >>$8.7 a litre right now TOO EXPENSIVE
alternate closed system
large long bags to prevent contamination but still making use of natural light and temperature
