By means of phototrophic biotechnology we aim to biologically incorporate valuable nutrients, such as nitrogen and phosphorus, from side and waste streams into high value microbial biomass (SCP). Depending on the final application of the produced biomass (food, feed, slow release bio-fertilizer), the influent scope ranges from domestic over industrial to agricultural or aquacultural streams (e.g. struvite (NH4MgPO4·6H2O), human urine,…).
In our current research the growth and nutritional composition of the commercially well-known green microalgae Chlorella vuglaris, Arthrospira platensis (Spirulina) and Dunaliella salina is studied and optimized. Microalgae offer an attractive solution in capturing and fixating nitrogen and phosphorus in aqueous waste streams and CO2 in gaseous waste streams. Moreover, microalgal biomass grows fast in comparison with conventional crops and contains a variety of interesting compounds such as essential amino and fatty acids, vitamins and antioxidants.
Also the influence of inhibitory and toxic components, i.e. NOx, SOx, on the growth, productivity and biomass composition of microalgae are important parameters to develop an economically feasible technology. In our research the tolerance level for CO2, O2 and some inhibitory components is determined in cultures of Nannochloropsis oculata. Furthermore, the effect of different concentrations of gaseous components (CO2, O2, NOx, SOx) and the ratio O2:CO2 on specific growth rate, productivity and biomass content is investigated.
Not only green microalgae receive our attention, diatoms are an extremely diverse group of unicellular algae that self-assemble a porous, intricate siliceous cell wall, called frustule. Such frustules possess a unique combination of physical and chemical properties (chemical inertness, high mechanical strength, large surface area, low density, good porosity and highly ordered features on nano to micro scale). The research aims to both, produce diatoms as a sustainable feed in aquaculture and to incorporate trace levels of titanium into their biosilica frustules (Photocatalysis). Diatoms are a promising feed for larvae in aquaculture to replace the conventional and unsustainable fish meal.
Purple Non Sulfur Bacteria (PNSB)
Next to the green microalgae and diatoms, the research aspires to grow Purple Non Sulfur Bacteria (PNSB) such as Rhodopseudomonas palustris and Rhodobacter capsulatus. The PNSB possess the interesting characteristics to be able to immobilise organic carbon extremely efficient and use light with wavelengths in the infra-red area (minimal energy input and prevent contamination).
Besides the terrestrial context, a dedicated focus is oriented toward biological life support systems for Space.