Methods for eliminationg bacterial infections in lignocellulosic material
Licentiate thesis, 2011
Bacterial infection is a major problem in industrial fermentations and may cause tremendous
losses in ethanol yield if not dealt with properly.
Lignocellulose is an inhibitory fermentation media which may impose increased stress on the
fermenting organism, Saccahromyces cerevisiae, often leading to a decreased cell viability
and fermentation performance deteriorating. This makes elimination and control of bacterial
infections troublesome. Within this project two methods for controlling bacterial infections in
lignocellulosic fermentations were investigated.
It was investigated how different cultivation conditions for the pitching agent influence the
ability of the culture to survive and boost the ethanol production capacity in an SSL-based
fermentation process. It was confirmed that the cultivation conditions play an immense role
for the performance of the pitching agent. Investigations on antimicrobial agents were also
performed and focused on sodium chloride and ethanol. It was found that a combination of
these decreased bacterial growth wile yeast viability was maintained.