BIOFUEL FROM ALGAE- MORE LIMITATIONS THAN POSSIBILITIES

If I am not mistaken, this is the second time when the possibility of using algae in biotechnology exploitation is receiving massive publicity. In the early seventies the focus is more in the production of SCP or single cell protein for animal feed. Nowadays, there is more talk about getting biofuel from the algal cells.
In theory this is a good idea as algal cells in the presence of light used photosynthesis to use carbon dioxide and release oxygen. In return not only you get the spin off benefits which are not only environmental friendly but even produce products as the substrate for fermentation to generate energy. It is simply a great ‘win- win’ situation for all.
However, in reality things are simply not as easy as it looks. From the point of mass culturing of the algal cells we have to depend on special bioreactors or fomenters called photo bioreactors. It is the kind of bioreactor where the algal culture are grown and mixed or circulated under conditions of light source to illuminate the algal culture for its source of energy.
The problems of bioreactors are clearly more seen at the level of scale up or using industrial size photobioreactors
At a large scale there are going to be problems faced in photo bioreactors. As we know the ideal photobioreactor is to get well mixed condition that encourage mass transfers. It is clear that there will be problems faced due to the lack of mechanical stirrers to carry out this job.
Using mechanical stirrers might create problems of shear forces which can break up the algal cells.
There is also the problem of supplying carbon dioxide mass transfers to supply to the algal cells at the scale of large photobioreactors
Light penetration into the medium is a real engineering biochallenge. Algal cell as suspended solids tend to block the penetration of light to all the algal cells.
The medium used for the algal cultivation must also clear enough to allow light penetration while at the same time provide nutrients to the algal cells
Sad to say, despite the potential or promises that algal cells can be used for biofuel it is still basically studies carried on laboratory scale and require a lot more research and heavy capital investments
Just because you are living in the sunny tropical country doesn’t always guarantee that the cultivation of algal cell by photo bioreactors is practical!!!



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