Biotechnological Generation of Value Added Products from Spent Pulping Liquors: Assessing the Potential of Extremophiles

Worldwide bio-economy concepts foster the conversion of biomass into a range of food, health, fiber, industrial products, and energy. However, there is a risk that the diversion of farmland or crops for the production of biofuels and bio-based products compromises the food supply-the food versus fuel dilemma. One way to circumvent this dilemma is the use of spent liquors from the pulping industry in terms of a wood biorefinery. The pulping process leads to a solid fraction mainly consisting of cellulose (pulp) and a liquid fraction containing a mixture of the other wood components and their degradation products, which can be further processed. The economical success of the utilization of these liquid fractions largely depends on an efficient separation and conversion of the organic compounds-predominantly the carbohydrates. Integrating biotechnological processes into existing pulp mills is expected to achieve those requirements. Employing extremophilic microorganisms, e.g. Acidothermophiles or Alkalithermophiles, in the bioprocesses could lead to further process intensifications by saving chemicals, cooling energy and sterilization steps.