The main objective of this study was to develop a system for the production of "renewable"
hydrogen. Paper sludge is a solid industrial waste yielding mainly cellulose, which
can be used, after hydrolysis, as a feed-stock in anaerobic fermentation by (hyper)thermophilic
organisms, such as Thermotoga elfii and Caldicellulosiruptor saccharolyticus. Tests
on different medium compositions showed that both bacteria were able to produce hydrogen
from paper sludge
hydrolysate, but the amount of produced hydrogen and the requirement for other components
differed. Hydrogen production by T. elfii strongly depended on the presence of yeast
extract and salts. By contrast, C. saccharolyticus was less dependent on medium components
but seemed to be inhibited by a component present in the sludge hydrolysate. Utilization
of xylose was preferred over glucose by C. saccharolyticus.