Evaluating scaling of capillary photo‐biofilm reactors for high cell density cultivation of mixed trophies artificial microbial consortia

Capillary biofilm reactors (CBRs) are attractive for growing photoautotrophic bacteria as they allow high cell-density cultivation. Here, we evaluated the CBR system's suitability to grow an artificial consortium composed of Synechocystis sp. PCC 6803 and Pseudomonas VBL120. The impact reactor material, flow rate, pH, O2, medium composition on biomass development long-term stability at different scales was studied. Silicone superior over other materials like glass or PVC due its excellent O2 permeability. High rates 520 μL min−1 prevented sloughing in 1 m capillary reactors, leading a 54% higher dry weight combined with lowest concentration inside compared standard operating conditions. Further increase length 5 revealed limitation trace elements. Increasing elements by factor five allowed complete surface coverage 36.8 g m−2 and, thus, successful scale-up 25. Practical application: Cyanobacteria use light energy upgrade CO2, thereby holding potential carbon-neutral production processes. One persisting challenges is low cell density limitations accumulation often occurring established flat panel tubular photobioreactors. Compared planktonic cultures, much densities (factor 10 100) can be obtained cyanobacterial biofilms. (CBR) offers good growth conditions biofilms, but applicability has been shown only laboratory scale. first study based sizing up performed, testing feasibility this system large-scale applications. We demonstrate that optimizing nutrient supply conditions, could enlarged 25 enhancing reactor. This concept, biofilms numbering up, holds applied flexible, platform value-added compounds.