PhD defence: Owik Matthias Herold-Majumdar
Owik Matthias Herold-Majumdar defends his thesis,
Second Generation Bleaching in Pulp and Paper Industry using Heme-thiol Peroxidases and Haloperoxidases
Professor Katja Salomon Johansen, IGN
Doctor Pedro Emanuel Garcia Loureiro, Novozymes
Professor Thomas Rosenau, University of Natural Resources and Life Sciences, Vienna
Professor Tapani Vuorinen, Aalto Unversity
Professor Lisbeth Garbrecht Thygesen (Chair), IGN
Soft and white toilet and tissue paper is natural in our everyday life. The bleaching process to obtain white paper from wood aims for separate the wood structure into single cellulose fibers and remove the colored part, called lignin. During the water intensive process of bleaching harsh, chlorine-based chemistry is used. This process is environmentally unfriendly and pollutes, for example water bodies, with hazardous organochlorine compounds, even after waste water treatment.
In this PhD thesis, it was investigated in a collaboration between the University of Copenhagen and Novozymes A/S whether enzymes can bleach paper pulp and remove hazardous byproducts from bleach plant waste water. The study used along lignin model compounds, industrial pulp samples and their filtrates to reproduce an authentic industrial environment in the laboratory. The study produced three main findings. First of all, a haloperoxidase from the fungus Curvularia verruculosa was able to modify the lignin model compounds which led to further experiments with the pulp and filtrates. Secondly, the use of haloperoxidases and peroxidases led to a reduction of color and persistent compounds in bleach plant waste water. Thirdly, it was shown that haloperoxidases can bleach pulp.
To sum up, these findings contributed to a better understanding of alternatives for conventional chemical pulp bleaching processes. Further studies will be required to fully understand the potential of enzymatic bleaching and implement an industrial scale process.
A digital version of the PhD thesis can be obtained from the PhD secretary Anne Marie Faldt email@example.com