An increasingly industrialised economy, a booming population and global warming have all renewed interest in research for a green and sustainable fuel source. Biofuels are fuels which are derived from a biological source such as plants, animals or algae. They are strong candidates in research for a feasible and sustainable fuel sources especially in developing countries. Biofuels are produced by processing sugars and oils found in plants to produce bioethanol, biodiesel and other products. Plants which are high in sugars and oils such as sugar crops, palm crop and soy beans are commonly used. Microalgae also accumulate lipids and sugars and so can be used to produce many types of biofuels.
In 1978 the United States Department of Energy launched the Aquatic Species Programme which focused on the production sustainable energy from microalgae . About 3,000 species of microalgae were screened for the feasible production of many biofuels. Lipids accumulated in microalgae can be chemically processed to yield fatty acid methyl esters (FAME). FAMEs can be used to power diesel engines. Carbohydrates in microalgae can be fermented by microbes or yeasts to make bioethanol or biobutanol both of which can be used as substitutes for petrol. Flexible fuel vehicles can used up 85% bioethanol blends.
Microalgae produce hydrocarbons when grown in high temperatures. Hydrocarbons are used in the aviation industry as a fuel. Biogas is produced by microalgae through anaerobic digestion, this can be converted into biomethane which can be a substitute for natural gas in heating, transport and electricity generation. Hydrogen can be directed made by some microalgae in the absence of oxygen, hydrogen is a zero emission fuel that can be used in car engines and liquid propellant rockets.
Microalgae accumulate much higher amounts of lipids than plants Microalgal oil as a replacement for palm oil and so much more efficient production of biofuels can be realised. They have no requirements for arable land and can be grown in sea. Industrial waste water and CO2 can be used as feed for microalgae and they help reduce global warming in this regard. They can also be genetically modified to optimise cost and energy inefficiencies associated with biofuel production. In the US alone now, there are over 30 companies working to produce economically viable biodiesel from microalgae and the research and development investment is in excess of several billion US dollars.
Solazyme is a San Francisco based biotechnology company that uses genetically modified microalgae to produce different types of biofuels including diesel and jet fuel.The microalgae are grown in dark stainless steel containers and fed sugar. some microalgae produce triglycerides like those found in palm oil and soy beans. Others produce hydrocarbons similar to crude oil.
Other companies which use microalgae for biofuel production include;
- Algenol Biofuels
- Blue Marble Production
- Sapphire Energy
- Diversified Technologies
- Origins oil incorporated
Microalgae occupy the same environment as many bacteria, fungi and parasites and naturally there is competition between species for space and resources. Some bacteria produce molecules that act on and kill competing bacteria to reduce competition. In fact, many antibiotics we use such as neomycin, streptomycin and tetracycline are made by one type of bacteria against others. Think of it as a tiny arms race amongst bacteria and we just use the weapons they make against each to combat bacterial infections.
As microalgae also compete with bacteria and many other pathogens for space and resources, perhaps they also make molecules that kill competing bacteria, viruses and fungi. In 1951 Pratt and his colleagues observed that open sewage that contains the microalgae Chlorella was contained fewer bacteria than sewage without Chlorella. This led to isolation of chlorellin an antibiotic made up of a mixture of fatty acids that acts against both gram positive and negative bacteria.
Another family of microalgae called cyanobacteria produce Curacin A which acts on the scaffolding of the cell called microtubules. Rapidly dividing cancer cells assemble these microtubules at a faster rate and so targeting them could stop cancer cells dividing, proliferating and causing disease. Spirulina produces calcium spirulan, a molecule which has been found to stop the replication of several viruses including influenza A virus, human cytomegaly virus, HIV-1 and measles virus.
It is important to note that just because a molecule acts against a pathogen does not mean it can be administered as a drug. There need to vigorous tests and trials to make sure it does no harm to your healthy cells and cause serious side effects. So far no molecules derived from microalgae are used as drugs.
Another way microalgae could be used to produce drugs could be through genetic modification to mass produce new and cheap drugs. I have explored this in Genetic modification of microalgae
Whether you know it or not, you have probably used many liters of palm oil over your lifetime. The stuff is in everything including food, cosmetics, soaps and even candles.
There is large destruction of the environment incurred in the production of palm oil including large scale deforestation and loss of habitat for many species like orangutans and the Sumatran tiger. The equivalent of 300 football fields are being destroyed every hour to make space for palm oil production.
Microalgae can be modified to produce C10 and C12 fatty acids found in palm oil. As they have much less demands for arable land and a considerably less environmental impact compared to palm trees. Microalgae could provide a solution to sustainable palm oil production to meet global demand.
Oil yields of various plants compared to microalgae (Gallons of oil per acre per year)
See more at: http://www.oilgae.com/algae/oil/yield/yield.html#sthash.J72jS924.dpuf
Companies such as Ecoever, a laundry detergent manufacturer have already begun making the switch to microalgae derived synthetic palm oil. Unilever, a consumer products giant has agreed to buy huge amounts of oil derived from microalgae from Solazyme. The oil will be used in its range of personal care products including Dove and Brylcreem.
Genetic engineering of microalgae to produce many viable high value products.
Genetic modification is the process by which altercations in the genes of an organism ultimately lead to changes in its physical characteristics. Genes are what makes us who we are and what makes us different from other people. All living organisms have genes. Genes come in the form of a long string like molecule called DNA and changes in genes called mutations manifest as physical changes in the organisms.
Changes in genes happen all the time. DNA is a relatively fragile molecule that is protected by the nucleus in almost every cell in the body. DNA is damaged and changed by many things including excess sunlight and smoking. It is these changes in DNA that manifest as hereditary diseases and sometimes cancer . It is also these changes in genes that give organisms strategic advantages over competitors and allows for evolution to occur.
Genetic modification is therefore, a worthy subject of scientific study. We have been genetically modifying organisms through selective breeding and other agricultural techniques for thousands of years. More recently however, since the discovery of the structure of DNA in 1953, there have been numerous advances in our understanding of DNA and how it is expressed in organisms. This has paved way for the development of technologies that can engineer the genomes of organisms for the production of many high value useful products.
Microalgae offer attractive potential for genetic modification to produce many high value products such as biofuels and new drugs. They grow very quickly and are safe to handle. Genetic modification of microalgae will aim to do one many things such as improving the efficiency at which microalgae convert sunlight and nutrients into energy. This will allow for the more efficient production of microalgal products.
Genetic engineering of microalgae also offer the prospect of pharming. Pharming is when genes which code for molecules of interest such as drugs and vaccines are inserted into the genome of an organism like microalgae. The microalgae will express the genes inserted and basically offer a cheap and efficient way of mass producing the said molecule. Pharming of microalgae could provide a cheap and sustainable way to mass produce drugs like insulin and many vaccines.
The ebola therapeutic ZMapp was developed using such methods. The genes coding for the protein were inserted into the chloroplast (light harvesting organ) of the tobacco plant. The plant expressed the genes and facilitated additional modifications that produced a fully functional therapeutic molecule against the Ebola virus. In theory then, microalgae also have chloroplast and perhaps they can be used to mass produce similar drugs. The added advantages of using microalgae instead of plants is that they can grow rapidly and be eaten directly by humans. They are quite nutritious in fact. Could microalgae offer the solution to deliver cheap and safe drugs that can be distributed easily around developing countries to combat epidemics?
Genetically engineered Dunaliella salina are being investigated as a way to orally vaccinate against hepatitis B. The New Ohio Sea Grant is currently investigating using genetically modified Chlamydomonas reinhardtii as a means of vaccinating trout from hematopoietic necrosis virus which kills 30% of the US trout population every year. Mosquito larvae feed on the microalgae, Chlorella so it provides a potential target in the global fight against malaria. Chlorella was engineered to produce the protein trypsin-modulating oostatic factor (TMOF) which interferes with the life cycle of the mosquito larvae. All larvae that fed on the microalgae died within 72 hours.