New Tube Format Speeds Up Photosynthetic Algal Growth

The “self-shading,” or “shadow,” effect happens when algae cells cast a shadow over their neighbors within a growing culture. The result is that cells in the shade do not receive the photons they need to grow. This reduces the algal growth rate, as well as it would for other cultures of photosynthetic microorganisms.

By designing a specialized tubing product with greater surface area than a comparable standard tube, Photosynthetic Technologies (PT) is offering an interesting option for algae cultivators to address this limitation.

With an undergraduate degree in Biology from Harvard University and an MBA in entrepreneurship from the FW Olin Graduate School of Business at Babson College, Jonathan L. Gal is the inventor of the AlgaTube™, the founder of Photosynthetic Technologies, and a PhD student in the Department of Microbiology and Molecular Biology at Brigham Young University.

Representation of the cross sections of the two tube types.

In a lab study, Mr. Gal demonstrated that a prototype of the AlgaTube produced 41% greater cumulative biomass production after 10 days of growth, when compared to a standard, cylindrical tube. A formal paper describing the four-times repeated experiment has been published by Applied Phycology, a British scientific journal affiliated with the British Phycological Society.

“The enhanced surface area causes the growth improvement by reducing the self-shading effect,” said Mr. Gal. “The AlgaTube prototype has a Photon Surface Area to Volume (PSA/Vol) ratio of 1.1x, compared to a PSA/Vol ratio of 0.5x for the Control tube. That is what makes the difference. Increasing the surface area exposes greater numbers of cells to incident photons at any moment in time. This boosts photon utilization and the overall growth rate of an aqueous, photosynthetic culture.”

The study was conducted with Arthrospira platensis, but Mr. Gal is confident that the results are transferrable to other photosynthetic microorganisms. “I believe that there will be statistically significant growth enhancement for any aqueous photosynthetic microorganism that is grown in the AlgaTube,” he said. “The scientific principle that drives the growth improvement applies equally to all photosynthetic microorganisms in aqueous culture, not just to A. platensis.

The AlgaTube will be manufactured by a contract manufacturer and marketed by Photosynthetic Technologies. PT launched a website earlier this month and is now taking pre-orders for the product.