Biopolymer Networks from Terrestrial and Aquatic Biomasses
Time: Mon 2025-06-02 10.00
Location: F3 (Flodis), Lindstedtsvägen 26 & 28, Stockholm
Language: English
Subject area: Fibre and Polymer Science
Doctoral student: Alina E. M. Schmidt , Fiber- och polymerteknologi, AIMES-Center for the Advancement of Integrated Medical and Engineering Sciences, Karolinska Institutet and KTH Royal Institute of Technology
Opponent: Professor Pedro Fardim, Chemical and Biochemical Reactor Engineering and Safety (CREaS), Department of Chemical Engineering, KU Leuven, Leuven, Belgium
Supervisor: Professor Ulrica Edlund, Polymerteknologi, AIMES-Center for the Advancement of Integrated Medical and Engineering Sciences, Karolinska Institutet and KTH Royal Institute of Technology; Professor Agneta Richter-Dahlfors, Fiber- och polymerteknologi, AIMES-Center for the Advancement of Integrated Medical and Engineering Sciences, Karolinska Institutet and KTH Royal Institute of Technology
QC 20250506
Abstract
Today’s sustainability challenges demand more than new materials - they require new ways of thinking about the resources we already have to support zero waste strategies. This thesis explores the valorization of underutilized biomasses - specifically the terrestrial crop Lupinus angustifolius (Lupin) and the marine macroalga Ulva fenestrata (Ulva) - as alternative feedstocks for bio-based materials. These two biomasses were selected for their dual functionality: both are already cultivated for food applications, yet their residual non-edible fractions remain largely unexplored. By combining structural biology, bioprocess engineering, materials science, and bioimaging, the thesis establishes a comprehensive, interdisciplinary framework for biomass characterization and conversion. Biopolymer mapping using multimodal fluorescence imaging and optotracing revealed the tissue architecture and native biopolymer distribution in Lupin residues and Ulva thalli. From Lupin, lignocellulose was extracted through mild alkaline pretreatment and defibrillated into lignin-containing microfibrillated cellulose (L-MFC). In Ulva, complex structural features, including oligo-/polyaromatic-rich layers and rhizoidal fibrillar structures, were discovered, prompting a redefinition of its tissue terminology. A decellularization-inspired approach was then developed to recover tissue scaffolds from Ulva, leveraging its naturally thin, two-cell-layered structure to remove cellular content while preserving scaffold integrity. Finally, two material design strategies were employed: a bottom-up approach for Lupin-derived L-MFC films, exploiting their nanoscale fibrillar network for structural organization, and a top-down approach for Ulva-based films, preserving the intrinsic tissue scaffold architecture. The resulting materials demonstrated structural integrity while preserving key biopolymer networks. Across the entire biomass-to-material workflow, multimodal fluorescence imaging combined with optotracing was integrated and adapted as a novel analytical tool, providing non-destructive, real-time and high-resolution information.