Alpha-L-rhamnosidase involved in ulvan degradation (Ref.2, PubMed:31285597). Ulvan is the main polysaccharide component of the Ulvales (green seaweed) cell wall. It is composed of disaccharide building blocks comprising 3-sulfated rhamnose (Rha3S) linked to D-glucuronic acid (GlcA), L-iduronic acid (IduA), or D-xylose (Xyl) (Probable). Alpha-L-rhamnosidase converts Rha-Xyl-Rha3S, the product of a sulfatase acting on Rha3S-Xyl-Rha3S oligosaccharides, to Rha and Xyl-Rha3S (PubMed:31285597). The enzyme is able to degrade p-nitrophenyl-alpha-L-rhamnopyranoside (PNP-Rha) in vitro (Ref.2). Hydrolysis of terminal non-reducing alpha-L-rhamnose residues in alpha-L-rhamnosides. By ulvan and rhamnose. Belongs to the glycosyl hydrolase 78 family. Truncated N-terminus.