Technology and Patents
Astrea is the brand name of the high end photobioreactors, in reference to the goddess of Greek mythology, in which she embodies purity and integrity.

The basis of the practice tried-and-tested Astrea photobioreactors is a closed circulation system, which, using efficient thin-film technology with minimal energy consumption, provides optimal growth conditions for phototrophic microorganisms. This innovative technology is protected worldwide by the patent WO 2010/115412 A29.

Process specifications of photobioreactors

  • suitable for fresh, brackish and salt water
  • temperature range of 5 to 45°C
  • pH range 1 to 12
  • disinfectable with hydrogen peroxide and chlorine
  • simple, modular scale up
  • suitable for a variety of microalgae species e.g.: Nannochloropsis, Tetraselmis, Phaeodactylum, Haematococcus etc.

Technical characteristics of the Astrea reactors

Plant size
Astrea 30…200K 24…205,000 L production capacity
glass tube diameter
39.6-60.6 mm
Cultural volume/floor space
61…110 L*m⁻²
Glass material
Borosilicate (degree of transmission > 95%, lifespan ≥ 50 years)
Glass tube wall thickness
1.8…3.2 mm
Glass tube loops
11…355 m
Number of modules
module length
1…100 m
Glass tubes in the module
Glass tube spacing
130…152 mm (vertical in module)
Glass tube spacing
156…178 mm (horizontal in the module)
Module distance
500…1,000 mm
System vessel
Stainless steel/PE, 5…9,000 L
System pump
Stainless steel/Noridur ® 1.4593 (duplex stainless steel), 5…1,200 m³*h⁻¹

The reactors consist of three basic units:

Photosynthesis modules with horizontally arranged glass tubes,

  • glass tube construction for the formation of long tube loops
  • glass tube arrangement with a support plate system for the carrier, fixation and height adjustment of the glass tubes
  • stranding for stabilization of the module system

Inoculation and running of a PBR

a long-term stable and innovatively built supply unit

  • functional system vessels for optimization of substance exchange processes
  • CAD-based engineering of manifold and collector systems
  • algae-adapted and process-validated system pump
  • process-optimized peripheral interfaces

a modern product-specific process control unit

  • measurement and regulation of optical density, pH, temperature, level
  • Measurement of oxygen and fluorescence
  • light-dependent pump speed
  • Data recording, exchange, remote access and export of process data via a web server

Reference plant projects

Astrea 115 K

Simris Alg, Hammenhög, Sweden
Floor area
about 1,900 m²
about 120 m³

Astrea 2KC

Salata AG, Ritschenhausen, Germany
Floor area
about 30 m²
about 2.1 m³

PBR 15K…50K

Salata AG, Ritschenhausen, Germany
Base area
about 1,900 m²
about 85 m³