Algae photobioreactor is a type of bioreactor which is used to cultivate micro and macroalgae. In a photobioreactor, the system uses the Sunlight to feed the photosynthetic organisms such as algae. However, photobioreactors are not so much popular as other bioreactors, but they are definitely developing rapidly for the ongoing research works on algae as well as a better understanding of the many advantages of algae culture. They are truly capable of efficiently growing algae culture by using only wastes from several industrial processes.
No doubt, algae are mostly grown in an open-air cultivation system until recently. However, there is always a chance of facing lots of challenges when cultivating algae in an open-air cultivation system, such as:
- Water evaporation
- Predators eating the algae culture
- Requirement of a large land
Besides that, setting up an open-air cultivation system is usually an expensive investment. So there is always a growing need of inventing a new cultivation system for algae cultures. In this regard, photobioreactors play a major role in solving the above challenges while increasing yields and production efficiencies simultaneously.
Types of Algae Photobioreactors
Nowadays, there are three types of algae photobioreactors, commonly used for algae cultivation, and they are:
- Flat Plate Photobioreactors
This type of photobioreactor simply consists of vertically arranged or inclined translucent rectangular boxes. These boxes are often separated into two parts to influence an agitation of reactor fluid. Additionally, these boxes are internally linked with each other for starting the process of emptying/filling and transporting nutritive substances. Quite often, flue gas is used at the bottom portion of the box to make sure that the CO2 has enough time to react with algae present in the flat plate photobioreactors.
- Tubular Photobioreactors
A tubular photobioreactor is made up of a series of horizontal or vertical arranged tubes that are connected together to a pipe system. These tubes are usually made from borosilicate glasses or transparent plastics. A pump is used for the constant circulation of algae-suspended fluids in this system. However, this type of photobioreactor often causes several problems like CO2 deficiency, high concentration of O2 at the end of the unit during the circulation, and many more. So, ultimately it makes the process inefficient. Besides that, there is always a chance of growing algae substances in the wall of this photobioreactor. As a result, it can inhibit the penetration of Sunlight.
- Bubble Column Photobioreactors
Bubble Column Photobioreactor comprises vertically arranged cylindrical columns consisting of transparent material. The introduction of gas occurs at the bottom of the column and discharges a turbulent stream to activate an optimum gas exchange. Usually, light is projected from outside the column. However, recent developments in the bubble column photobioreactor provide us the opportunity to introduce lights inside the column. As a result, it increases light distribution as well as light penetration.
Advantages of Algae Photobioreactors
No doubt, algae photobioreactors provide more advantages than the open-air cultivation system. Some of these advantages are listed below:
- Algae grow in such a place where no other crop will grow
- Very easy to grow algae
- Energy received from algae is totally renewable
- Able to sequester the same amount of carbon compared to other open-air cultivation systems
So, there is no way to deny the usefulness of algae photobioreactors. Algae photobioreactors have truly unleashed the greater potential for algae cultivation in a wide variety of commercial and industrial applications.