The glass tubing behind a 22 percent surge in algae production yields

Some of the biggest innovations in algae production can come from the smallest of improvements. Algae companies are hard at work experimenting with variations in equipment and processes, seeking better ways to grow their strains of algae into commercially viable fuels, feed, nutraceuticals, and cosmetics, among other products. These building blocks of progress have improved understanding of algae production and are shifting the way algae is grown. And small changes are making a big difference.

The glass tubing used to grow algae cultures from seed, for example, continues to prove critically important in commercially viable algae enterprises, and small adjustments to the tubing can have a big influence on yield.

How glass tubing aids in algae production

Algae production starts in photobioreactors (PBRs) and is often moved to outdoor tanks to continue growth on a larger scale. But recent advancements to seed PBRs have shown that production on a commercial scale can occur in these closed systems.

Tubular glass PBRs are protected from environmental factors that are detrimental to algae growth, keeping strains safe from bio-contamination. The glass tubing itself is resistant to ultraviolet light, chemicals, scratches, and corrosion. But the most important benefit of closed glass PBR systems is that they’re highly productive, yielding a higher biomass output per production space versus outdoor pools. SCHOTT and other algae companies have been experimenting with PBR tubing, using thinner walls or an oval shape, for example, to extend those yields.

At Heliae, an Arizona-based commercial algae producer, we’ve been testing oval CONTURAX glass tubing in the company’s Helix seed PBRs, and some early results are stunningly positive: This tubing can help increase the growth rate, and ultimately the production, of algae strains in seed reactors.

Heliae retrofitted some Helix seed PBRs with SCHOTT’s oval CONTURAX glass tubes. While these tubes reduce the total internal volume of the PBR by about 15 percent compared to traditional circular tubes, the elliptical structure increases the total surface area and light penetration, which has a profound impact on algae growth rates.

Using the oval tubes, the Helix reactor saw algae growth rate per volume increased by more than 45 percent, and dry biomass output per day increase by more than 22 percent over the course of the multi-month experiment. The thin walls and shape of the tubing allowed more light to penetrate the glass, causing increased photosynthesis and a significant surge in growth.

After these positive findings, Heliae plans to transition the Helix platform from a small seed reactor to a small- to medium-scale production PBR. The company will also equip other reactors with SCHOTT’s oval tubes.

Progress, one step at a time

The progress realized at Heliae is a positive sign for the commercial development of other strains of algae. And because these glass tubes have a 50-year lifespan, the process is highly consistent and reliable for algae production companies. Glass maintains its transparency throughout its lifespan, unlike polymer tubes that become opaque after a few years — or even months — of sunlight exposure, depending on climate conditions and the degree of exposure. By law of nature, 1 percent more sunlight equals 1 percent more algae production, and the higher light transmission of glass tubes brings light to algae for many years.

The CONTURAX installed in the Helix reactor is a small piece to the larger puzzle of enhancing the growth rate and output of algae. But the results were a big leap forward in more efficient, more cost-effective algae production.

April 28, 2015


Suzann Erben
SCHOTT North America, Inc.