title: Monoseptic cultivation of phototrophic microorganisms--development and scale-up of a photobioreactor system with thermal sterilization.
abstract: The use of phototrophic microorganisms as sources of biological active substances in photoautotrophic and mixotrophic cultivation modes requires an adequate cultivation system with thermal sterilization. A corresponding photobioreactor system in the 10, 25 and 100 l scales was developed. This "Medusa"-photobioreactor system represents a concept based on the air-lift loop principle, whose working volume is irradiated by external light sources. The incident irradiation can be varied by a light control system. An effective CO(2)/O(2) gas exchange is enabled due to the efficient supply with process gas by several gas supply nozzles within the system and a large degassing surface. Using a model to describe the growth characteristics of the organisms, the volumetric irradiation coefficient I(DX) was defined as scale-up parameter. On this basis the scale-up from 1 l bubble columns to the 10 and 100 l scales was realized. The scale-up was performed successfully with Chlorella salina as model organism. A maximum biomass concentration of 7.89 g (dry weight) l(-1) at a maximum specific growth rate of 0.058 h(-1) and a yield of 35 mg l(-1) h(-1) was obtained in a batch cultivation in the 100 l scale under photoautotrophic conditions with an initial biomass concentration of approx. 0.03 g l(-1).
authors.affiliation: Bioprocess Engineering, Friedrich-Alexander University Erlangen-Nuremberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany. christian.walter@bvt.uni-erlangen.de
authors.forename: Christian
authors.initials: C
authors.lastname: Walter
authors.forename: Torsten
authors.initials: T
authors.lastname: Steinau
authors.forename: Norbert
authors.initials: N
authors.lastname: Gerbsch
authors.forename: Rainer
authors.initials: R
authors.lastname: Buchholz
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D002455:Cell Division / Q000502:physiology / Q000528:radiation effects; D002708:Chlorella / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects*; D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D008027:Light; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism*; D010865:Pilot Projects; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D013242:Sterilization / Q000379:methods*
chemical_list: D002734:Chlorophyll; D010100:Oxygen; D000077194:Chlorophyll A