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Fermentative hydrogen production and bacterial community structure in high‐rate anaerobic bioreactors containing silicone‐immobilized and self‐flocculated sludge
Author(s) -
Wu ShuYii,
Hung ChunHsiung,
Lin ChiNeng,
Chen HsinWei,
Lee AnSheng,
Chang JoShu
Publication year - 2005
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20800
Subject(s) - hydraulic retention time , bioreactor , chemistry , sucrose , fermentative hydrogen production , anaerobic exercise , biomass (ecology) , chromatography , hydrogen production , effluent , hydrogen , food science , biohydrogen , environmental engineering , biology , organic chemistry , physiology , agronomy , engineering
A novel continuously stirred anaerobic bioreactor (CSABR) seeded with silicone‐immobilized sludge was developed for high‐rate fermentative H 2 production using sucrose as the limiting substrate. The CSABR system was operated at a hydraulic retention time (HRT) of 0.5–6 h and an influent sucrose concentration of 10–40 g COD/L. With a high feeding sucrose concentration (i.e., 30–40 g COD/L) and a short HRT (0.5 h), the CSABR reactor produced H 2 more efficiently with the highest volumetric rate ( ${\nu}_{{\rm H}_2}$ ) of 15 L/h/L (i.e., 14.7 mol/d/L) and an optimal yield of ca. 3.5 mol H 2 /mol sucrose. The maximum ${\nu}_{{\rm H}_2}$ value obtained from this work is much higher than any other ${\nu}_{{\rm H}_2}$ values ever documented. Formation of self‐flocculated granular sludge occurred during operation at a short HRT. The granule formation is thought to play a pivotal role in the dramatic enhancement of H 2 production rate, because it led to more efficient biomass retention. A high biomass concentration of up to 35.4 g VSS/L was achieved even though the reactor was operated at an extremely low HRT (i.e., 0.5 h). In addition to gaining high biomass concentrations, formation of granular sludge also triggered a transition in bacterial community structure, resulting in a nearly twofold increase in the specific H 2 production rate. According to denatured‐gradient‐gel‐electrophoresis analysis, operations at a progressively decreasing HRT resulted in a decrease in bacterial population diversity. The culture with the best H 2 production performance (at HRT = 0.5 h and sucrose concentration = 30 g COD/L) was eventually dominated by a presumably excellent H 2 ‐producing bacterial species identified as Clostridium pasteurianum . © 2005 Wiley Periodicals, Inc.