Physiological and genetic studies towards biofuel production in cyanobacteria

The main aim of this thesis was to contribute to the optimization of the cyanobacterial cell factory and to increase the production of cellulose as a biofuel (precursor) via a physiological and a transgenic approach. Chapter 1 provides an overview of the current state of cyanobacterial biofuel research and contains a detailed description of bacterial cellulose synthesis and regulation. Chapters 2, 3 and 4 focus on improving photosynthetic efficiency and describe our findings on how the photosynthetic machinery in the cyanobacteria Synechocystis sp. PCC 6803 responds to conditions of energy limitation and energy excess, we also describe how regulation may occur, specifically regarding state transitions. Additionally, in chapter 2 a new technique to directly measure the redox state of the PQ pool is introduced and we describe how different measuring techniques and growth conditions can affect results. Chapters 5 and 6 describe our efforts in producing cellulose as and extracellular biofuel via a physiological and a transgenic approach respectively. In chapter 5 we try to maximize cellulose production in the natural cellulose producing cyanobacteria Crinalium epipsammum and in chapter 6 we introduce cellulose synthase genes into Synechocystis sp. PCC 6803. In Chapter 7 all aspects of this thesis are discussed.