Production of various carboxylated CNCs from beer residuals

  • Timo Pääkkönen (Speaker)
  • Laleh Solhi (Contributor)
  • Miikki, K. (Contributor)
  • Yingfeng Wang (Contributor)
  • Kontturi, E. (Contributor)

Activity: Talk or presentation typesConference presentation


This work is a continuation of studies on the hydrolysis of cellulose in a gas/solid system utilizing pressurized HCl gas in a custom-built reactor [1] and preparing carboxylated CNCs from BC [2]. Work is based on the earlier work with dry fibers hydrolyzed to their leveling-off degree of polymerization (LODP) subsequently dispersed into cellulose nanocrystals (CNCs) [3,4]. Now, we introduce a process which uses beer residuals as a raw material for CNCs. Beer residuals is a side stream which is globally produced millions of tons annually. However, this side stream of brewing industry is lacking valuable industrial end uses. Mashing process, which is applied to dissolve carbohydrates for beer production, increases significantly cellulose content of fibrous side stream. Hot alkali extraction of beer residuals removes over 80 % of non-cellulose components. NaClO2/HCl hydrolysis continues cellulose purification and lowers DP of cellulose to the level which is suitable for CNC dispersion. Carboxylic groups are introduced on the surface of cellulose with TEMPO-oxidation. Hydrogel, which is purified with centrifuge, is finally dispersed with microfluidizer. Here, we compare whole grain oat and barley as raw materials of beer residual CNCs. Both grains are suitable raw materials for carboxylated CNCs which have still appearance of hydrogel after dispersion.
[1] Pääkkönen et al. React. Chem. Eng. 2018, 3, 312-318
[2] Pääkkönen et al. ACS Sustainable Chem. Eng. 2019, 7, 14384-14388
[3] Kontturi et al. Angew. Chem. Int. Ed. 2016, 55, 14455-14458
[4] Lorenz et al. Faraday Discuss. 2017, 202, 315-330
Period14 Jun 2022
Held atDepartment of Bioproducts and Biosystems
Degree of RecognitionInternational


  • HCl gas hydrolysis
  • humin formation
  • NaClO2
  • carboxylated CNCs
  • beer residual
  • TEMPO oxidaton
  • alkali extraction