Axenic cultivation of anoxygenic phototrophic bacteria, cyanobacteria, and microalgae in a new closed tubular glass photobioreactor

Abstract

A low-cost closed tubular glass photobioreactor allowing axenic cultivation of phototrophic microorganisms was constructed. Standard glass tubes were arranged in a helical array providing a working volume of 80 1. The glass tubes were connected with a degassing chamber, which also provided ports for measuring and regulating oxygen supply, pH, foam, and optical density and for adding substrates and antifoam agents as well as disposing of vent gas. A pump module allowed agitation of the medium in the bioreactor at a laminar flow rate of 1.5 m/s. Upstream of the pump module a gas inlet was located, allowing efficient mixing of the used gases with the medium. The temperature of the medium was controlled by a Pt-100 sensor and by a heat exchanger with an effective surface of 0.12 m2 connected to an external thermostat. Irradiation was provided by three light panels each consisting of ten fluorescent tubes. The entire photobioreactor - apart from the light panels and motor - could be sterilized at 121 degrees C in an autoclave. In addition to a detailed description of this photobioreactor, we report on first experiments to cultivate the anoxygenic phototrophic bacteria Rhodobacter sphaeroides and Rhodospirillum rubrum, the oxygenic phototrophic cyanobacterium Synechocystis sp. strain PCC6803, and the microalga Chlorella sp. in this photobioreactor.

Isolation of Cyanophycin-degrading Bacteria, Cloning and Characterization of an Extracellular Cyanophycinase Gene (cphE) from Pseudomonas anguilliseptica Strain BI

“…strain PCC6308 was cultivated in full-strength BG11 medium (23) in an 80-liter closed tubular glass photobioreactor as described before (24). Also, a recombinant E. coli DH1 harboring plasmid pMa/c5-914::cphA (see above) with a temperature-sensitive inducible promoter was employed for the production of CGP.…”

Synthesis and Accumulation of Cyanophycin in Transgenic Strains of Saccharomyces cerevisiae

“…For the production of CGP at a technical scale, cyanobacteria were shown to be unsuitable due to their low cell densities and polymer contents (3.5% [wt/wt]) and slow growth and circumstantial growth conditions in a photobioreactor (18,19 Also, in the industrially relevant bacteria Pseudomonas putida, Ralstonia eutropha, and Corynebacterium glutamicum, considerable amounts of CGP could be produced after heterologous expression of cphA (3,13,48,49). Recently, CGP production was also achieved for the first time in eukaryotic organisms.…”

“…For the production of CGP at a technical scale, cyanobacteria were shown to be unsuitable due to their low cell densities and polymer contents (3.5% [wt/wt]) and slow growth and circumstantial growth conditions in a photobioreactor (18,19). In contrast, much higher amounts of the polymer were produced with the heterotrophic bacterium Acinetobacter baylyi strain ADP1 (46% [wt/wt]) (14) and with recombinant strains of E. coli (24% [wt/wt] [15] and 34.5% [wt/wt] [21], respectively).…”

Photofermentative Hydrogen Production in Outdoor Conditions

“…The tubes have diameters ranging between 3 and 6 cm and length between 10 and 100 m [31]. The PBRs fall under different categories: simple airlift or agitated bubble column (vertical type) [41][42][43][44], horizontal or nearly horizontal tubular PBRs [28,38,45] and helical type PBRs [46][47][48]. Tubular PBRs can be scaled-up by connecting a number of tubes to manifolds, but the length of the tubes is limited by the accumulation of gas [31].…”