Biochemical characterization of a new ulvan lyase and its applicability in utilization of ulvan and preparation of ulva oligosaccharides

Ulva is globally distributed specie and has a high economic value. Ulvan is one of the main active substances in Ulva, which has a variety of biological properties. Ulvan lyase degrades ulvan through a beta-elimination mechanism which cleaves the beta-glycosidic bond between Rha3S and GlcA or IdoA. The complex monosaccharide composition of ulvan makes it promising for use in food and pharmaceutical applications. This thesis explores a putative ulvan lyase from Alteromonas sp. KUL_42. We expressed and purified the protein, performed a series of characterizations and signal peptide had been removed. The results showed that the protein molecular weight of ULA-2 was 53.97 kDa, and it had the highest catalytic activity at 45 degrees C and pH 8.0 in Tris-HCl buffer. The K-m and V-max values were 2.24 mg.mL(-1) and 2.048 mu mol.min(-1).mL(-1), respectively. The activity of ULA-2 was able to maintain more than 80% at 20 similar to 30 degrees C. ESI-MS analysis showed that the primary end-products were mainly disaccharides to tetrasaccharides. The study of ULA-2 enriches the ulvan lyase library, promotes the development and high-value utilization of Ulva resources, and facilitates further research applications of ulvan lyase in ulva oligosaccharides.

Automated summary

Ulva is a globally distributed specie with high economic value. This study explores a putative ulvan lyase from Alteromonas sp. KUL_42 and characterizes its properties. The results showed that the ulvan lyase had high catalytic activity and could maintain its activity within a certain temperature range. This study enriches the ulvan lyase library and promotes the development and utilization of Ulva resources.