Premium
Influence of substrate concentration on the stability and yield of continuous biohydrogen production
Author(s) -
Kyazze G.,
MartinezPerez N.,
Dinsdale R.,
Premier G.C.,
Hawkes F.R.,
Guwy A.J.,
Hawkes D.L.
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.20802
Subject(s) - biohydrogen , chemistry , sucrose , hydraulic retention time , substrate (aquarium) , yield (engineering) , fermentative hydrogen production , propionate , continuous stirred tank reactor , bioreactor , hydrogen production , hydrogen , chromatography , nuclear chemistry , biochemistry , materials science , organic chemistry , waste management , effluent , oceanography , engineering , metallurgy , geology
The effect of substrate concentration (sucrose) on the stability and yield of a continuous fermentative process producing hydrogen was studied. High substrate concentrations are attractive from an energy standpoint as they would minimise the energy required for heating. The reactor was a CSTR; temperature was maintained at 35°C; pH was controlled between 5.2 and 5.3, and the hydraulic retention time (HRT) was 12 h. Online measurements were taken for ORP, pH, temperature, %CO 2 , gas output and %H 2 , and data logged using a MatLAB® data acquisition toolbox. Steady‐state operation was obtained at 10, 20 and 40 g/L of sucrose in the influent, but a subsequent step change to 50 g/L was unsustainable. The hydrogen content ranged between 50% and 60%. The yield of hydrogen decreased as the substrate concentration increased from 1.7 ± 0.2 mol/mol hexose added at 10 g/L, to 0.8 ± 0.1 mol/mol at 50 g/L. Sparging with nitrogen improved the hydrogen yield by at least 35% at 40 g/L and at least 33% at 50 g/L sucrose. Sparging also enabled steady‐state operation at 50 g/L sucrose. Addition of an extra 4 g/L of n ‐butyric acid to the reactor operating at 40 g/L sucrose increased the butyrate concentration from 9,830 to 18,900 mg/L, immediately stopping gas production and initiating the production of propionate, whilst the addition of 2 g/L taking the butyrate concentration to 12,200 mg/L did not do so. It was shown that operation at 50 g/L sucrose in a CSTR in butyrate fermentation is possible. © 2005 Wiley Periodicals, Inc.