Ciliates Removal in Microalgae Culture using Foam Column Separation Technique

Over the years algae has drawn the attention of various groups within the field of biotechnology. However, its production and efficient harvesting at scale still pose considerable challenges. Similarly, obtaining a desired algae specie/strain free from contaminants is another bottleneck that needs to be tackled as most algae are contaminated by other unwanted organisms such as ciliates.

To overcome these biological contaminant challenges, many techniques have been employed. These techniques include but are not limited to the use of chemicals additives, filtration techniques and the manipulation of the environmental conditions such as light, air and pH level. The employment of these techniques is not without challenges, such as negative effects on the desired algae specie and lack of in-depth research in some areas.

However, to overcome these problems, this research work will focus on the use of a low cost foam column separation technique that could be used to remove the biological pollutants from the algae culture leaving behind the desired algae specie in the culture medium for further downstream processing or dewatering. The algae “Chlorella vulgaris” and ciliates “Tetrahymena pyriformis” will be used as the desired test organisms. The surfactants SDS will be used to aid the removal of the ciliates. The harvesting will be conducted in a semi-batch foam column apparatus with different factors of gas flow rate, column height, residence time and surfactant concentration. To get the optimum conditions, these variables and their various combinations will be assessed using Minitab 17 and other factorial design software.

Finding a cost effective way in dealing with biological pollutants in algae culture would improve the economics of algae biofuel production as well as the production of monospecific algae that could be used in the food and cosmetics industries.