Using bacteria as a launderette

25 Mar 2015

Combine superheated steam with enzyme technology and you can convert grass, straw, plant stems and manure fibre into sugars. Those sugars can be used in all sorts of ways, from animal feed and biogas to raw material for the green chemical industry. We put three questions to the project coordinator, Bioclear’s Jeroen Tideman, on the TKI (Knowledge and Innovation Top Consortia) project Fermentation 2.0.

Superheated steam, a thermal pretreatment technology for biomass

Bioclear started out 26 years ago as a University of Groningen spin-off company with the mission of using biological processes to make the world cleaner, more sustainable and safer. Bioclear is particularly interested in biological soil cleanup: for instance, the technologists developed a method for dealing with contamination under houses using bacteria instead of excavating the soil using machinery, which is expensive and labour-intensive. To put it simply, the bacteria that break down the contamination – which are already present in the soil – are pumped out with the groundwater, allowed to multiply and reintroduced so that they can work faster. And it was this speeding-up process that Bioclear found to be an interesting subject for collaboration with TNO, as Tideman explains.

How did Bioclear and TNO get together?

‘At a symposium in Wageningen I got talking to TNO researcher Johan van Groenestijn, who was giving a presentation on superheated steam (SHS), a thermal pretreatment technology for biomass. We both thought it would be a good idea to combine SHS with enzyme technology based on fungi. Thus it was that the TKI project Fermentation 2.0 began on 1 January 2014. In addition to TNO we’re collaborating with knowledge supplier Ekwadraat, the Southern Agriculture and Horticulture Organization ZLTO and three firms with their own fermenters, De Betonpleats, Jansen Wijhe and Schaap Bio-energie. The Ministry of Economic Affairs is providing financial support. TNO is doing the digestion tests, we’re doing the fermentation tests and the enzyme treatment, and Ekwadraat is organizing the business case. The farmers involved ensure that we have a link with the market.’

What makes this project so worthwhile?

‘Our society increasingly needs to produce biogas from the variety of biomass residues available. These materials are largely made up of lignocellulose, a tight complex of cellulose, hemicellulose and lignin which is difficult to ferment because of the low accessibility of these substances. The result is that the biomass is not fully converted, reducing the economic viability of fermentation. Better and faster conversion of the source materials could be a solution. This project should eventually make it possible to produce up to twice as much biogas from the same amount of biomass in the same fermenter in the same time, at a lower production cost.’

Has it turned out as you expected?

‘There are a variety of digestion technologies that haven’t been looked at closely, for example because they require too much heat. Thanks to the TNO professionals we now have a technology that works. The technical results are promising: the yield is indeed higher and the process is speeded up enormously. In consultation with the consortium Ekwadraat is currently calculating whether this does actually translate into a lower cost price for green gas. The next step is to turn residues into sugar water, which can be used as a raw material in the chemical industry. This second-generation sugar doesn’t compete with food, so it’s an interesting proposition for making the Dutch chemical industry greener. The fact that the technology works, the economics work, and we can apply it – that’s what gives me a kick.’


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