The pulp and paper industry may serve as a backbone in the change from a fossil-based into a bio-based economy. Already today beside the main product cellulose, tall oil, turpentine and energy are produced. However, the potential is much higher and therefore cascade raw material utilization targeting bulk chemicals like acetic acid, formic acid or lactic acid needs to be addressed. To address the topic of an increased use of wood in the way of cascade raw material utilization in the pulp- and paper industry, an ambitious consortium from national and international partners consolidated. Focus of the project is to isolate carboxylic acid from side streams of the KRAFT process, especially from the pulping process before the remaining stream is used for energy utilization. Goal of the project is the development of a multi-stage process for the isolation of carboxylic acids from kraft pulping. Besides the isolation the optimization of the acid concentration in the regarded streams is investigated. Based on the results of the optimized acid concentration and a technology check for potentially used technologies a concept for further process integration shall be developed.