Molecular-level architecture of Chlamydomonas reinhardtii’s glycoprotein-rich cell wall

Abstract

Microalgae are a renewable and promising biomass for large-scale biofuel, food and nutrient production. However, their efficient exploitation depends on our knowledge of the cell wall composition and organization as it can limit access to high-value molecules. Here we provide an atomic-level model of the non-crystalline and water-insoluble glycoprotein-rich cell wall of Chlamydomonas reinhardtii. Using in situ solid-state and sensitivity-enhanced nuclear magnetic resonance, we reveal unprecedented details on the protein and carbohydrate composition and their nanoscale heterogeneity, as well as the presence of spatially segregated protein- and glycan-rich regions with different dynamics and hydration levels. We show that mannose-rich lower-molecular-weight proteins likely contribute to the cell wall cohesion by binding to high-molecular weight protein components, and that water provides plasticity to the cell-wall architecture. The structural insight exemplifies strategies used by nature to form cell walls devoid of cellulose or other glycan polymers.

The Microalgae <em>Chlamydomonas </em>for Bioremediation and Bioproduct Production

“…For bioethanol production, the high carbohydrate content present in both the cellulose and hemicellulose cell walls, as well as the starch-based cytoplasm, is broken down into monomeric sugars during enzymatic hydrolysis prior to fermentation. However, the cell wall of Chlamydomonas is not made of cellulose like in plants, but of five dense glycoprotein-rich layers [154]. Therefore, efforts have been focused on utilizing starch-rich Chlamydomonas for the production of bioethanol.…”