Complete genome sequencing of Vibrio species utilizing ulvan

Marine macroalgal species have gained considerable global attention as renewable biomass sources. Among the three main divisions of macroalgae (red, brown, and green algae), green algae remain largely unexploited. As a consequence of the strong environmental impact of these green seaweeds, interest in exploiting such natural resources has increased significantly, especially for its long-chain polymer part, ulvan. The main constituents of ulvan are 3-sulfated rhamnose (Rha3S), D-glucuronic acid (GlcA), L-iduronic acid (IdoA), and D-xylose (Xyl). The repetition moieties are disaccharides composed of Rha3S linked with GlcA or IdoA, termed ulvanobiuronic acid A or B, respectively, or xylose in lower amounts. Conversion of polymers into fermentable oligomers requires chemical or biological breakdown. However, the process of chemical conversion could be very expensive and not suitable for economical large-scale production. Enzymatic hydrolysis has been suggested as a more environmentally and economically viable treatment because of its low energy requirements and low byproduct production. Thus, the discovery of new enzymes for ulvan degradation is a key step for the better management and utilization of this resource.