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Photobioreactor set to mass produce biodiesel fuel from algae

LOS BANOS, LAGUNA, Sept. 29 –- Scientists at the College of Engineering and Agro-Industrial Technology (CEAT) and Institute of Biological Science of the College of Arts and Sciences (ULPB have developed an unassuming, and somewhat crude looking equipment that could mass produce biodiesel fuel from algae, commonly known as “pond scum.”

The contraption, called “photobioreactor, houses and cultivates algae, providing them a suitable environment for growth and supplying light, nutrients, air and heat to the culture, UPLB scientists said.

During the past many years and until today, the cultivation of the rapidly-growing algae is mostly done through the 'batch system' on ponds of seawater, minimizing the use of fertile land and fresh water.

”While the process (ponds or open system) processing succeeded in producing “Microalgae” referred to the “Third Generation” biofuel that is expected to become the ultimate source of energy in the future, especially for the transport sector, it can only produce at least 15 times more oil per hectare than alternatives such as grape seed, palm soya and jatropha, scientists said.

Today, solution to the problems or at least some part it, could very well be found in the CEAT complex in the form of an unassuming, if somewhat crude looking equipment.

The photobioreactor, which comes in two prototype variants, was developed by CEAT with Prof. Rex B. Demafelis, convenor of the UPLB Alternative Energy RDE, at the helm.

The development of the photobioreactors was funded by the Philippine Council for Aquatic and Marine Research and Development or PCAMRD under the program leadership of Dr. Milagrosa M. Goss, a UPLB Professor Emeritus.

A photobioreactor is an enclosed, illuminated culture vessel designed for controlled biomass production of phototrophic liquid cell suspension cultures.

Phototrophs are organisms that carry out the process of photosynthesis to acquire energy like plants, planktons, certain bacteria, and algae.

The design and fabrication of the photobioreactor prototypes fell on the able hands of Prof. Demafelis. With the help of CEAT undergraduate students, he came up with two prototypes: an internally illuminated vertical column photobioreactor and an externally illuminated vertical column draft-tube airlift photobioreactor. The externally illuminated photobioreactor uses natural light (direct sunlight or any ambient light) while the internally illuminated prototype uses artificial light.

Inside the closed vessel, algal cells grow in aqueous suspension where they have more efficient access to water, carbon dioxide, and dissolved nutrients. Through the photobioreactors, microalgae are capable of producing large amounts of biomass and usable oil which can then be turned into biodiesel.

Prof. Demafelis said that after establishing the viability of C.vulgaris (algae specie) as a fuel feedstock, they validated its efficacy through the engineering design of the photobioreactors.

“We are confident that once we have the oil we can convert it to biodiesel. Where do we get the oil? Everything points to third generation biofuel feedstock,” he said.

Although the photobioreactors have several major advantages over open systems (ponds), i.e., they can prevent or minimize contamination and prevent water evaporation, their use typically entails huge production and processing costs.

Certain requirements of photobioreactors such as cooling, mixing, and control of oxygen accumulation make these systems more expensive to build and operate than ponds.

But the photobioreactors developed by CEAT are noteworthy for their simplicity and use of cheap, if not somewhat crude materials, that work effectively just the same.

Moreover, they can be easily constructed and replicated, Demafelis said.

The best part is that baseline results of the prototypes have been very encouraging so far. Compared to conventional methods like batch system, the photobioreactor prototypes showed good benchmark results in the laboratory setting. For one thing, algae harvest is far bigger. And because it is a continuous system, it is cost-efficient in terms of productivity volume and mass of harvested algae, he stressed, UPLB scientists said.

Conversely, like other photobioreactors of its kind, CEAT’s photobioreactors are prone to innate disadvantages of such systems like contamination.

But Prof.Demafelis says the practical solution is to simply seed the microalgae continuously so it will overcome the contaminants.

The basic technology is commendable enough as it is but Demafelis insists that there’s more to be done to further enhance the design and efficiency of the photobioreactors.

He said they are looking forward to eliminating the artificial light because it is energy intensive.

Eventually, they also want to make use of raw materials that have negative cost index such as water effluents, waste water, and agri-run off which contain the necessary nutrients for the algae to thrive.(PNA)


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