Speciality glass manufacturer Schott has said its new oval glass tubes for photobioreactors (PBRs) increase maximum dry biomass output by more than 22% a day.

In a study in partnership Heliae, a technology-driven algae production company, the Schott round glass tubes were retrofitted with oval tubes in Heliae’s Helix seed PBR.

An indoor study over multiple cycles in several months found that the algae growth rate per volume increased by more than 45%, while the oval shape reduced the total internal volume of PBR tubes by 15% compared to standard circular tubes, resulting in the overall output increase stated above.

The oval cross section increased the tube's surface area that is oriented towards the light source. More of the algal culture was reached by light, stimulating photosynthesis and enhancing algae growth.

Also, the final maximum culture density increased by more than 25% due to the efficient light exposure of the algae culture.

"The results of this study reflect the hypotheses presented in our original computer simulations, and demonstrate the advantages of glass tubing for algae production,” said Dr Nikolaos Katsikis, Director of Business Development at Schott Tubing.