Algal bloom

Having been recently involved on a research project, I asked myself “What has a mechanical engineer got to do with microalgae?” The first thing that came to my mind was their biological nature and small size. It would probably be best to leave biologists to study these things. But curiosity got the better of me, while researching I found an article on a book entitled Physics of the Future written by renowned physicist and futurist Michio Kaku. He mentioned that in the next 50 to 100 years algae would play a vital role in the advancement of technology and the human race.

So what are microalgae? Microalgae are mostly unicellular organisms with a measurement from a few micrometers to hundreds of micrometers, 1x10-6 m. In Filipino terms, they are collectively known as “lumot.” They live through the photosynthesis process which would require sunlight and carbon dioxide to produce oxygen as a by-product. With proper amounts of light, carbon dioxide, and essential nutrients, they reproduce in a short amount of time, with some species having just four to six hours doubling time. Algae usually thrive in a wide range of conditions, from the tropics to the coldest climates. They are usually cultured and grown for fish feeds. However, researchers have also long known that algae contain oil which can be converted to biofuels. Biofuels from microalgae are more environmental friendly than fossil fuels as they generate less greenhouse gas emissions over their life cycle.

At the De La Salle University, we recently hosted Dr. Joel Cuello, the lead researcher of the Biosystems Engineering group at the University of Arizona. He gave a talk on the potential of microalgae as a raw material for various products in the Philippines. He also mentioned that the Philippines is blessed to have a lot of indigenous species of microalgae. Another advantage is that our tropical climate is conducive to year-round cultivation of algae. Since various types of microalgae can produce high-value commodities such as antioxidants, carotenoids, fatty acids, enzymes, polymers, toxins, and even hydrogen, the economic potential of a microalgae-based industry is significant. Its products can be used in pharmaceutical goods, pet feeds, cosmetics, biofuel, and so much more. Microalgae are very good mediums for CO2 sequestration. For example, power plants can set up a microalgae cultivation pond to capture CO2 from flue gas that would otherwise just be released into the atmosphere.

In the energy sector, production of biofuels (e.g., biodiesel and bioethanol) is one of the potential applications of microalgae. Microalgae produce fatty acids which can be processed to biodiesel. At the same time, they also produce carbohydrates which can be used for bioethanol production. In the Philippines, there are existing government mandates that prescribe the blending of biofuels with gasoline and diesel to enhance energy security and reduce CO2 emissions. The drive to meet the policy demand creates pressure to produce large quantities of biofuels in the country. The gap lies in the implementation of the technology to support the goal of the legislation.

The processing of microalgae to biofuels presents a different path compared to the conventional agricultural processing of feedstock to biofuels which uses much land area for production. Microalgae can be grown in lesser land areas since they can be cultivated in photobioreactors or in raceway ponds. Photobioreactors present a very reliable and productive process; however, its operating cost is high. On the other hand, the raceway pond is a cheaper way of producing microalgae but the yield depends on the weather, which makes production unpredictable. Upon harvesting, the microalgae are dewatered, dried, and made ready for oil extraction or fermentation to produce biodiesel or bioethanol.

Aside from biofuels, microalgae can also be converted to hydrogen used in fuel cells that can power vending machines, vacuum cleaners and highway road signs. Furthermore, miniature fuel cells can be used for cellular phones, laptop computers and portable electronic devices. Multiple pathways in a system can be combined to generate multiple products which would greatly maximize the production of microalgae. An example is the integrated biorefinery system. My current research involves the optimization of a microalgal biorefinery system which considers the water footprint, carbon footprint, and land footprint as main constraints. This entails qualifying the different pathways to produce multiple products while maximizing economic potential.

Algae are an untapped resource and we are blessed with more than a thousand species. The weather is in our favor too for cultivating these algae. Moreover, we have the manpower and technology to implement a pilot project on algal system. However, we need the collaboration of our brightest engineers and researchers plus the support from the government and private sectors to finance and develop such studies. The possibilities are countless… algal bloom might just be what we need for a brighter tomorrow.

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Engr. Aristotle T. Ubando is a graduate of Masters of Science in Mechanical Engineering at the University of the Philippines-Diliman. He is currently an assistant professor of the mechanical engineering at the De La Salle University (DLSU) and an active researcher of DLSU’s Center for Engineering and Sustainable Development Research (CESDR). His research interests include process cybernetics, energy systems modeling, life-cycle assessment, and computational fluid dynamics. As a Ph.D. candidate in the mechanical engineering department, his dissertation leads to the design of microalgal biorefinery systems. He may be contacted via e-mail [email protected].