A novel bioreactor containing self-flocculated anaerobic granular sludge was developed for high-performance hydrogen production from sucrose-based synthetic wastewater. The reactor achieved an optimal volumetric hydrogen production rate of ~7.3 L/h/L (7.150 mmol/d/L) and a maximal hydrogen yield of 3.03 mol H2/mol sucrose when it was operated at a hydraulic retention time (HRT) of 0.5 h with an influent sucrose concentration of 20 g COD/L. The gasphase hydrogen content and substrate conversion also exceeded 40 and 90%, respectively, under optimal conditions. Packing of a small quantity of carrier matrices on the bottom of the upflow reactor significantly stimulated sludge granulation that can be accomplished within 100 h. Among the four carriers examined, spherical activated carbon was the most effective inducer for granular sludge formation. The carrierinduced granular sludge bed (CIGSB) bioreactor was started up with a low HRT of 4-8 h (corresponding to an organic loading rate of 2.5-5 g COD/h/L) and enabled stable operations at an extremely low HRT (up to 0.5 h) without washout of biomass. The granular sludge was rapidly formed in CIGSB supported with activated carbon and reached a maximal concentration of 26 g/L at HRT = 0.5 h. The ability to maintain high biomass concentration at low HRT (i.e., high organic loading rate) highlights the key factor for the remarkable hydrogen production efficiency of the CIGSB processes.

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Among four cellulolytic microorganisms examined, Cellulomonas biazotea NCIM-2550 can grow on various cellulosic substrates and produce reducing sugar. The activity of cellulases (endoglucanase, exoglucanase, and cellobiase), xylanase, amylase, and lignin class of enzymes produced by C. biazotea was mainly present extracellularly and the enzyme production was dependent on cellulosic substrates (carboxymethyl cellulose [CMC], sugarcane bagasse [SCB], and xylan) used for growth. Effects of physicochemical conditions on cellulolytic enzyme production were systematically investigated. Using MnCl(2) as a metal additive significantly induces the cellulase enzyme system, resulting in more reducing sugar production. The efficiency of fermentative conversion of the hydrolyzed SCB and xylan into clean H(2) energy was examined with seven H(2)-producing pure bacterial isolates. Only Clostridiumbutyricum CGS5 exhibited efficient H(2) production performance with the hydrolysate of SCB and xylan. The cumulative H(2) production and H(2) yield from using bagasse hydrolysate (initial reducing sugar concentration = 1.545 g/L) were approximately 72.61 mL/L and 2.13 mmol H(2)/g reducing sugar (or 1.91 mmol H(2)/g cellulose), respectively. Using xylan hydrolysate (initial reducing sugar concentration = 0.345 g/L) as substrate could also attain a cumulative H(2) production and H(2) yield of 87.02 mL/L and 5.03 mmol H(2)/g reducing sugar (or 4.01 mmol H(2)/g cellulose), respectively.

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