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CM slurry AS231115Carlos Martín and Bio4Energy colleagues have developed a one-step biomass conditioning-and-conversion process which could bring cost-efficiency to cellulosic ethanol production. Photo by Bio4Energy.Bio4Energy researchers have invented a process which could bring greater certainty of cost efficiency to industrial biorefineries that choose to base their operations on lignocellulosic input materials such as wood from spruce or pine trees.

Currently the U.S.A. and Italy are among few countries in the world to host industrial biorefineries for the production of ethanol based on cellulose via the biochemical conversion route using industrial enzymes and yeast. However, these biorefineries mainly use agricultural residue as feedstock in their operations.

While advanced bio-based production is seen as a great opportunity in several richly forested countries in the boreal belt, industrial operators there are up against a practical problem. A large part of the Canadian, Swedish and Finnish forest resource is made up of coniferous tree species whose woody composition is highly complex and requires harsh treatment before rendering its cellulose, hemicellulose and lignin components in separate parts, which is a requirement in most bio-based production. This harsh pre-treatment means toxic elements are left in the biomass slurry resulting from the process, whose impact must be reduced for efficiency to be achieved in the conversion step to fuels and chemicals.

A new invention by Bio4Energy researchers and partners is designed to tackle this very problem. In a techno-economic analysis, which is part of a package of four scientific articles, they outline a method for decreasing toxicity while increasing product yields by adding a certain chemical compound (sodium sulphite) in the conversion of the pre-treated biomass to bioethanol fuel, in this case.

The techno-economic evaluation showed that, by adding the sodium sulphite chemicals and thus conditioning or "detoxifying" the biomass-based slurries that resulted from the pre-treatment, less enzymes and less yeast were required to perform the conversion, while the yield of sugar to be transformed into biofuel rose.

"The aim of the enzymatic reaction is to produce sugar from cellulose. If we use [our new] method you get more sugar from the cellulose. This is a yield-dependent process. The second type of reaction [is] a conversion of sugar to a fermentation product. That product could be ethanol as here or any type of fermentation product you can [make] with yeast. We want a higher yield and we don't want to wait a long time to get it. [Our] invention improves the amount of product that we get and that is true for both these steps", said research group leader This email address is being protected from spambots. You need JavaScript enabled to view it., professor at Umeå University in Sweden.

"Secondly, [our method] is compatible with enzymatic saccharification and fermentation. The problem with many detoxification methods is that they have to be done as a separate step. Here you can combine it… [in] one step with the enzymatic saccharification and microbial fermentation", Jönsson went on;

"A third thing is the cost for this treatment… This is a way that is realistic to do in industrial scale".

Sodium sulphite is already in use as an additive in the pulping and textile industries, but is has not previously been added as a reducing or detoxifying agent in biofuel making on an industrial scale (for bulk production).

The new process including its combined detoxification and conversion step has been tested with good results at the Biorefinery Demonstration Plant at Domsjö Fabriker industrial complex at Örnsköldsvik, Sweden.

"This is an opportunity that investors of future biorefineries in Scandinavia should not ignore, because otherwise the whole process of converting cellulose to ethanol, for instance, could be much more difficult to achieve… It would be slower and could be much more expensive. So if we are thinking of industrial implementation of cellulosic ethanol, this should definitely be on the table", said This email address is being protected from spambots. You need JavaScript enabled to view it., co-author of the techno-economic evaluation and a researcher on the Bio4Energy Biochemical Platform.

"It decreases the investment risk if you have a process based on softwood", such as spruce or pine, Jönsson concurred.


Collaborators on this project/package of articles:

Umeå University, Sweden 

Leif Jönsson - Bio4Energy Biochemical Platform (leader)

Carlos Martín Medina - Bio4Energy Biochemical Platform

This email address is being protected from spambots. You need JavaScript enabled to view it. - Bio4Energy Biochemical Platform

This email address is being protected from spambots. You need JavaScript enabled to view it. - Bio4Energy Biochemical Platform

SP Processum, Sweden

Björn Alriksson, SP Processum

SEKAB E-Technology, Sweden

Marlene Mörtsell

Umeå University and Bio4Energy issued a press release retelling the content of this news item.

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