**Preface to "Advances in Oligosaccharides and Polysaccharide Modifications in Marine Bioresources"**

Oligosaccharides and polysaccharides derived from marine bioresources are sustainable materials that are synthesized via seaweed photosynthesis. These are widely used by aquatic organisms and human beings as valuable foodstuffs and industrial raw materials, respectively. Seaweed polysaccharides have various structures depending on their origin, such as red algae, green algae, and brown algae. They exhibit various functionalities depending on small structural differences. This Special Issue includes content that will deepen our understanding of marine polysaccharides and oligosaccharides, e.g., the functional analysis of enzymes, the production of specific structural saccharides using specific enzymes, and the elucidation of their new functionality. We hope that this book will facilitate the achievement of a sustainable society by providing modified sustainable resources.

> **Yuya Kumagai, Hideki Kishimura, and Benwei Zhu** *Editors*
