Thermophilic biohydrogen production from glucose with trickling biofilter

Thermophilic H 2 production from glucose was studied at 55–64°C for 234 days using a continuous trickling biofilter reactor (TBR) packed with a fibrous support matrix. Important parameters investigated included pH, temperature, hydraulic retention time (HRT), and glucose concentration in the feed. The optimal pH and temperature were 5.5 and 60°C, respectively. With decreasing HRT or increasing inlet glucose concentration, volumetric H 2 production rate increased but the H 2 production yield to glucose decreased gradually. The biogas composition was almost constant at 53 ± 4% (v/v) of H 2 and 47 ± 4% (v/v) of CO 2 . No appreciable CH 4 was detected when the reactor was under a normal operation. The carbon mass balance showed that, in addition to cell mass, lactate, n ‐butyrate, CO 2 , and acetate were major products that comprised more than 85% of the carbon consumed. The maximal volumetric H 2 production rate and H 2 yield to glucose were 1,050 ± 63 mmol H 2 /l·d and 1.11 ± 0.12 mol H 2 /mol glucose, respectively. These results indicate that the thermophilic TBR is superior to most suspended or immobilized reactor systems reported thus far. This is the first report on continuous H 2 production by a thermophilic TBR system. © 2004 Wiley Periodicals, Inc.