Characterization of terrestrial cyanobacteria to increase process efficiency in low energy consuming production processes

Abstract

Terrestrial cyanobacteria have seldom been used for biotechnological processes, even though they offer great potential for new pharmaceutical products or other value-added substances. Particularly cyanobacteria of xeric habitats are of biotechnological interest, because they tolerate high temperatures, are desiccation-tolerant and feature low water consumption. In addition, the cyanobacteria collected in deserts are able to produce more photoprotective agents than their counterparts from other habitats, because of their genetical preadaptation. In this study, carotenoid and chlorophyll content of two representative terrestrial cyanobacteria strains, i.e. Nostoc muscorum and Leptolyngbya spec. sampled in Columbia (USA) and Soebatsfontein (RSA), were studied after exposure of the strains to different light conditions and cultivation temperatures. A temperature raise from 17°C to 30°C led to an increase of 46% in chlorophyll a content as well as an increase of 39% in carotenoid content of Nostoc muscorum. An irradiation raise from 19 μmol m-2s-1 to 125 μmol m-2s-1 resulted in an increase of a 10 to 20 times higher chlorophyll content. Additional results from light-curves support the potential future use of terrestrial cyanobacteria within low energy biotechnological processes using a novel type of photobioreactor to reduce the downstream process costs and nutrients needed during the cultivation. Results indicate that especially light intensity optimization currently holds unused potential.