Subitec GmbH

Spirogyra is a green filamentous freshwater algae on which recent studies reveal several promising properties and potential application possibilities in biotechnology. However, little is known about cultivation of Spirogyra and even less about large-scale cultivations in closed growth systems. Therefore, the aim of the present study was to elaborate the growth kinetics of Spirogyra sp. in a commercially available and scalable photobioreactor. For this purpose, Spirogyra sp. was grown indoors in distinct flat-panel airlift photobioreactors equipped with culture-flow directing installations. Hereby, special attention was laid on light administration and specific light availability and it was found that Spirogyra sp., in combination with the photobioreactor in question, required high photon-flux densities (100 µmol m^-2 s^-1 g_DW^-1) for maximum proliferation which is in accordance with its abundance in epipelagial waters in nature. Applying photon-flux densities of up to 1400 µmol m^-2 s^-1, a maximum volumetric productivity and final biomass concentration of 1.15 g_DW L^-1 day^-1 and 14.28 g_DW L^-1 were achieved, respectively, the highest to be reported for the alga. To the knowledge of the authors, this is the first report on the growth of Spirogyra in a flat-panel photobioreactor.

A review.Global net primary production of biomass has faded dramatically over the past few decades as a consequence of the increasing population and its infrastructure demands.Photosynthetic microorganisms constitute the substructure of the water based food chain and are characterized by a five- to tenfold higher surface area productivity in comparison to traditional terrestrial crops.Based on their larger areal productivity they are an expandable and so far sparsely utilized resource in terms of biotechnol.In addition, extended utilization in a sustainable form decreases anthropogenic carbon dioxide emission.Furthermore, the production of valuable compounds, for example, for pharmaceutical and cosmetically applications without genetic modification, is broadly possible by simple modification of cultivation parameters.For application of these benefits to the preservation of the livelihood of mankind, sustainable (phototrophic) production and utilization paths need to be designed beyond arable land use for food productionThe present chapter describes the basics of microalgal biol. as well as basic and advanced process design aspects.Industrially relevant open and dosed cultivation systems, namely, open ponds and photobioreactors, are elucidated and compared in terms of design, costs, and process stability as well as performance, energy consumption, and potential products.The conclusion gives an overview of prospects and future challenges.