Our project addressed the under utilization of sugar residual streams from the pulp industry. Plant dry matter, the so called lignocellulosic biomass, is the largest renewable biomass feedstock on Earth. Biorefineries processing such feedstock are projected to make a substantial contribution to a future sustainable economy. By 2030 we have the potential to develop a competitive bio-based European economy producing 30% of our chemicals and 25% of transport fuels, safeguarding millions of jobs. There are numerous lignocellulosic biorefineries in operation today, e.g. sulfite pulp mills in Finland, Norway, Sweden, Austria, Czech, Switzerland, USA and Canada, and several sugar beet biorefineries in UK and Finland. In the last years 5 full scale plants have been put in operation; 1 in Italy, 2 in US and 2 in Brazil. Unfortunately, lignocellulosic biorefineries struggle with low profitability. Such biorefineries have sugar streams that are not converted to higher value chemicals. Some produce low value ethanol (€0.3-0.6 /kg), but most incinerate their sugar to energy use by lack of other alternatives. These companies could therefore be more competitive by adding production of high value products from the sugar platform.
Being able to convert these large amounts of residual sugars (over 14 MT/y in EU alone) will obviously have great economical, and environmental benefits for the society. Instead of using sugars that originate from food, such as corn starch, sugar beet and sugar canes for the fermentation of chemicals, it is desirable to use sugars originating from industrial processes such as the pulp industry, that anyway produce cellulose. It will increase job opportunities, will strengthen the economy, and may help to change the demography of agriculture, from sugars to microbial fermentation to growing food for people.
The overall objective was to utilize these sugar streams that contain inhibitors and complex sugar mixtures that are currently unsuitable for microbial fermentation of high value chemicals, for which we were very successful. In addition, we managed to exploit these sugars and produce high value (>100 USD/kg) compounds that have great benefits in medicine, and are valuable as food and feed additives.