Introduction
Current situation
Expected scientific breakthroughs in production of photosynthesis-based biofuels
Improvement of photon-to-fuel conversion efficiency (PFCE)
Second generation biofuels–sourced from biomass not competing with food production
Bioenergy crops grown on marginal lands
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Enhancement of photosynthesis. This concerns both the optimising of the light-capturing antenna size and the electron transduction efficiency to maximally sustain the CO2 fixation capacity (Maurino and Weber 2013). Big efforts are currently put to introduce the C4 carbon fixation pathway to less efficient C3 plants and similar benefits, i.e. elimination of energy-consuming photorespiratory pathways, can be obtained by introducing inorganic carbon pumps from photosynthetic microorganisms, like algae and cyanobacteria, to C3 plants (Singh et al. 2014). Introduction of entirely new CO2 fixation and metabolic pathways in plants is likewise possible by making use of approximately 5000 metabolic enzymes known to occur in nature (Bar-Even et al. 2010).
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Enhancement of stress tolerance of plants. It has been envisioned that, e.g. by intervention of ABA signalling by small molecules could help plants to combat stresses like drought, cold and soil salinity, typical to marginal lands suitable for bioenergy/biofuel crop cultivation. Similarly, many strategies are under development to improve plant strategies to combat against biotic stress. Further, the nutrient stress is often strongly limiting the yield and novel results from metabolome studies have recently given new hopes to design plants more tolerant, for example, against phosphorus deficiency.
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Breeding of plants for improvement of nutrient uptake and water use efficiency or the shaping of plant architecture to optimise light use efficiency are all important traits to improve biofuel production.