High-rate ethanol production at low pH using the anaerobic granular sludge process

High-rate ethanol production at low pH using the anaerobic granular sludge process

Tamis, J. (TU Delft BT/Environmental Biotechnology; Paques B.V.)
Joosse, B.M.
de Leeuw, K.D. (TU Delft Education and Student Affairs)
Kleerebezem, R. (TU Delft BT/Environmental Biotechnology)

2021

In this study, we investigated the operational performance and product spectrum of glucose-fermenting anaerobic granular sludge reactor at pH 4. A selective environment for the growth of granules was implemented by the introduction of a 2 min settling phase, a hydraulic retention time of 6 h and a solid retention time of 12 ± 3 days. The fermentation products were ethanol, lactate, and volatile fatty acids (VFA) with yields of 0.55 ± 0.03, 0.15 ± 0.02, and 0.20 ± 0.04 gram chemical oxygen demand (gCOD)/gCOD glucose, respectively. The obtained product spectrum was remarkably different from the VFA-dominated product spectrum reported in a previous study when the same system was operated at higher pH (4.5–5.5). The shift in product spectrum coincided with a shift in the microbial community structure with the dominance of eukaryotic Candida tropicalis, Pichia jaroonii, and prokaryotic Lactobacillus species instead of the Clostridia species obtained at higher pH-values. The control of the microbiomes and the associated product spectra provides bioprocess engineers with the option to tailor a suitable precursor compound mixture for subsequent chain elongation fermentation or PHA biopolymer production.

ethanol
granular sludge
open/mixed culture fermentation
resource recovery
VFA

http://resolver.tudelft.nl/uuid:5c1769a3-143a-4e83-9c33-b211e785c1e5

https://doi.org/10.1002/bit.27708

0006-3592

Biotechnology and Bioengineering, 118 (5), 1943-1950

Institutional Repository

journal article

© 2021 J. Tamis, B.M. Joosse, K.D. de Leeuw, R. Kleerebezem