The conversion of forest and agricultural residues to liquid fuels is of
increasing interest worldwide as it provides quick and medium-term
solutions to the replacement of fossil fuels in the transport sector
without competing with the food supply.
This paper gives a comprehensive review of the research achievements
obtained within the most important processing steps in the
biomass-to-ethanol process. It also summarizes the most important research
challenges remaining in order to make the process economically feasible in
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"...will also speed up the transition from fossil fuels
to a renewable fuel-based transportation sector, which will
help diminish the impact of an increasing greenhouse effect
on our climate."
It describes recent achievements, with a focus on research performed at
Lund University, and, within these key processes, steps which mainly
consist of conversion steps, i.e., the pretreatment of biomass, enzymatic
hydrolysis, and the fermentation of both hexose and pentose sugars. It also
stresses the importance of optimizing the integration of process
engineering, fermentation technology, enzymatic and metabolic engineering.
Would you summarize the significance of your paper
in layman's terms?
The paper shows that great progress has been achieved within the
development of individual steps in the process for the production of
ethanol from cellulose-containing materials, such as wood residues, straw,
It also presents the authors' ideas about what remains to be done to move
from these research achievements toward a commercial process, including the
verification of pilot- and demo-scale plants, and integrating ethanol
production with the external fuel processes required by power plants.
How did you become involved in this research and
were any particular problems encountered along the way?
As a chemical engineer, I've been involved in this research for a period of
almost 30 years and, due to my knowledge of distillation, which was
considered a key step in achieving high energy demand, I soon realized that
this was not the case, and my research instead focused on the biomass
pretreatment and process integration.
To cope with all the challenges in developing a biomass-to-ethanol process
requires cooperation between various disciplines, primarily including
chemical engineers, microbiologists, and biochemists. This cooperation was
established at Lund University around 1985 and is an ongoing process, as
outlined in the list of the paper's authors.
Where do you see your research leading in the
My team will continue to develop pretreatments for various kinds of
biomasses and also intensify our research work on process integration, both
within the ethanol production process and also within external processes.
The latter comprises integration with first-generation ethanol production,
e.g., ethanol from wheat + wheat straw and from molasses + sugarcane
bagasse, and also includes integration with heat and power production.
Cooperation with other disciplines is foreseen to continue and comprises a
link with various industrial partners who are running the pilot- and
Do you foresee any social or political
implications for your research?
I believe that research performed by my group, in collaboration with other
similar research groups and industrial partners, will assist in the
development of economically viable processes for the production of ethanol,
resulting in heating and power production.
This will also speed up the transition from fossil fuels to a renewable
fuel-based transportation sector, which will help diminish the impact of an
increasing greenhouse effect on our climate.
Guido Zacchi, Ph.D.
Department of Chemical Engineering
Lund, Sweden Web