Hydrogen is considered one of the renewable energy sources of the future. It is a major component of fuel cells, which are presently being used in environment-friendly "hybrid cars". The production of biomass-derived hydrogen (by thermochemical or fermentative processes) puts into focus the use of renewable resources such as perennial grasses, fast growing trees, and others. Researchers from the Agrotechnology and Food Sciences Group of the Wageningen University and Research Centre (Netherlands) investigated the use of alkali-pretreated perennial grass (Miscanthus), for hydrogen production by a thermophilic anaerobic fermentation process. Anaerobic bacteria (Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana) were the microorganisms used in the fermentation. The microorganisms were shown to "simultaneously and completely utilize all pentoses, hexoses and oligomeric saccharides up to a total concentration of 17 grams per liter in pH-controlled batch cultures. T. neapolitana showed a preference for glucose over xylose, which are the main sugars in the hydrolysate. Hydrogen yields of 2.9 to 3.4 mol hydrogen per mol of hexose, corresponding to 74 to 85% of the theoretical yield". The full paper appears in the open access journal, Biotechnology for Biofuels (URL above)..