Developments in 2,3-butanediol production from biomass
Rehap is an EU project that is making biobased materials from agroforestry waste. Recently, it has achieved success in developing methods for producing 2,3-butanediol (BDO) from bark and poplar.
Rehap partners TECNALIA have been working on a process which uses the cellulosic residue generated by the purification of lignin from the woody material, poplar, and breaks it down via hydrolysis into its simplest sugars. Tests selected the best enzymes and hydrolysis conditions for maximising glucose yield and minimising the production of inhibitors that could affect fermentation at the next step. The hydrolysate (the substance left over from hydrolysis) was best obtained using the purification method, otherwise enzymes remained in their crude form and could not be used.
Once the substance was obtained, BIOSYNCAUCHO, a company that aims to develop high-added value chemical products from renewable raw materials, tested and determined the best conditions for the fermentation of sugars to 2,3-butanediol (BDO), a renewable chemical building block. Promising results from poplar’s second-generation sugars have revealed close comparisons to 2,3-BDO production using first generation sugars (sugars found in food crops using standard processing technologies).
In parallel to this research, Rehap partners VTT Technical Research Centre of Finland developed a technique for the hot water extraction of tannins from soft wood bark and successfully transferred it to the lab at the Bio Base Europe Pilot Plant (BBEPP). There, this technique to extract sugars and lignin/tannin fractions was successfully scaled-up to pilot scale.
The fermentation of the sugars obtained from bark in BBEPP at pilot scale has also been optimised by BIOSYNCAUCHO, with excellent results in terms of 2,3-BDO production, yield and productivity. As found with the process used in poplar, the purification procedures are critical to avoid the presence of inhibitors.
These two results demonstrate that the use of second generation sugars from agroforestry waste, obtained after the processing of bark and poplar, is a real alternative to using first generation sugars for the production of 2,3-BDO.
