Multifeed simultaneous saccharification and fermentation enables high gravity submerged fermentation of lignocellulose.
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 2015

Today, second generation bioethanol production is becoming established in production plants across the world. In addition to its intrinsic value, the process can be viewed as a model process for biotechnological conversion of recalcitrant lignocellulosic raw materials to a range of chemicals and other products. So called High Gravity operation, i.e. fermentation at high solids loadings, represents continued development of the process towards higher product concentrations and productivities, and improved energy and water economy. We have employed a systematic, model-driven approach to the design of feeding schemes of solid substrate, active yeast adapted to the actual substrate, and enzymes to fed-batch simultaneous saccharification and co-fermentation (Multifeed SSCF) of steam-pretreated lignocellulosic materials in stirred tank reactors. With this approach, mixing problems were avoided even at water insoluble solids contents of 22%, leading to ethanol concentrations of 56 g/L within 72 hours of SSCF on wheat straw. Similar fermentation performance was verified in 10 m3 demonstration scale using wheat straw, and in lab scale on birch and spruce, using several yeast strains. The yeast was propagated in the liquid fraction obtained by press filtration of the pretreated slurry. Yet, even with such preadaptation and repeated addition of fresh cells, the viability in the SSCF dropped due to interactions between lignocellulose-derived inhibitors, the produced ethanol and the temperature. Decreasing the temperature from 35 to 30°C when the ethanol concentration reached 40-50 g/L resulted in rapid initial hydrolysis, maintained fermentation capacity, lower residual glucose and xylose and ethanol concentrations above 60 g/L.


kinetic modeling





fed-batch high gravity


Carl Johan Franzén

Chalmers, Biologi och bioteknik, Industriell bioteknik

Ruifei Wang

Chalmers, Biologi och bioteknik, Industriell bioteknik

Johan Westman

Chalmers, Biologi och bioteknik, Industriell bioteknik

Charilaos Xiros

Chalmers, Biologi och bioteknik, Industriell bioteknik

Rakesh Koppram

Chalmers, Biologi och bioteknik, Industriell bioteknik

Elia Tomas-Pejo

Chalmers, Biologi och bioteknik, Industriell bioteknik

Lisbeth Olsson

Chalmers, Biologi och bioteknik, Industriell bioteknik

Recent Advances in Fermentation Technology (RAFT 11), Clearwater Beach, Florida, USA, November 8-11, 2015. Oral presentation.


Hållbar utveckling


Industriell bioteknik



Annan industriell bioteknik



Livsvetenskaper och teknik (2010-2018)

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