ABSTRACT
In a sustainable society, the major part of transport energy and of the materials will have to be derived directly from oxygenic photosynthesis. Various ways to achieve this, via the use of mass cultures of either cyanobacteria or eukaryotic algae, are currently under development. Most of these initiatives are classified as second-, third-, or fourth-generation biofuel approaches, but another significant difference is whether one initially aims at the formation of biomass or on an intracellular or extracellular product. Nevertheless, the most stringent constraint in all these developments is the energetic efficiency of product formation. In most processes, one makes use of dense suspension cultures in advanced photobioreactors. Light harvesting efficiency is therefore a key element in the overall efficiency of biomass and/or product formation in these processes. This efficiency is not only subject to various endogenous mechanisms of regulation but can also be modulated through genetic engineering, particularly of the antenna content and antenna composition of the production organisms. Here, we will describe how cyanobacteria and microalgae may be used to contribute to increased sustainability of society and review how modulation of their antenna size may contribute to this.
