13-19: Stable second generation bioethanol production in high temperature fermentations

Thermophilic ethanol production from diverse biomass sources is of great potential as part of the future renewable energy supply. BioGasol ApS has developed a stable, cost-effective and scalable fermentation for processing pretreated lignocellulosic materials in high DM fermentations without the use of any cost enhancing detoxification steps. The center in this anaerobic high temperature fermentation is the metabolically engineered production organism Pentocrobe^TM 411, which has ethanol yields close to the theoretical limit and conversion rates higher than 95% on both C₅ and C₆ sugars.  

Traditionally, ethanol production is performed in batch or fed batch fermentations. Running a continuous fermentation will have profound impact on the feasibility and economy of the future production scale as costly downtime is circumvented and inhibitory compounds generated in the pretreatment are continuously processed by the adapted organism. Pentocrobe^TM fermentation in batch- and continuous modes are compared regarding stability, nutrient demand and productivity.  

Earlier studies have investigated the inhibitory effect of both the substrate related inhibitors such as 2-furaldehyde and 5-hydroxymethylfurfural (HMF) and the product ethanol concentration. In the present study the combined effect of temperature, substrate and production inhibition is investigated in continuous reactors, as it is of major importance in the scaling process.