Dissertation

Unraveling modular architecture and domain engineering of carbohydrate-active enzymes: key insights for sustainable bio-based processes

This thesis examines enzyme domain architecture and engineering to improve the breakdown of lignocellulose and starch, abundant biopolymers crucial for sustainable biofuel and biochemical production. Carbohydrate-active enzymes (CAZymes) facilitate this degradation, but the structural complexity of these biopolymers limits enzyme efficiency.

Author: A. Sidar
Date: 03 December 2024
Links: Thesis in Leiden Repository

To address this, this study investigates CAZymes with modular architectures, focusing on enzymes from Aspergillus and Streptomyces microorganisms, known for diverse enzymes equipped with carbohydrate-binding modules (CBMs). The structural diversity of CAZymes in these genera provides a model for designing more efficient enzymes. Genomic and proteomic analysis across eight Streptomyces strains revealed significant variation in CAZyme domain organization, with certain strains proving effective at breaking down rice straw. Furthermore, tests on engineered GH13 amylase variants in Aspergillus niger showed that integrating N-terminal CBMs significantly enhances starch degradation. Moreover, enzyme engineering improved lignocellulose degradation through modified Streptomyces laccase. Additionally, a wide range of modular arrangements in GH3 β-glucosidases was identified, offering potential for activity enhancement. Taken together, the research reveals diverse modular CAZymes in Aspergillus and Streptomyces. Findings emphasize that not only binding and activity domains but also linker regions between them are essential for effective enzyme design, promoting the enzyme performance for sustainable applications across bio-based products.