Biochemical Properties of a New Polysaccharide Lyase Family 25 Ulvan Lyase TsUly25B from Marine Bacterium Thalassomonas sp. LD5.

Danni Wang,Guoyun Li,Yongqing Fu,Yujiao Li,Qi Zhang,Chengying Yin,Lu Han,Feng Han,Wengong Yu,Xia Zhao

doi:10.3390/md20030168

Abstract

Marine macroalgae, contributing much to the bioeconomy, have inspired tremendous attention as sustainable raw materials. Ulvan, as one of the main structural components of green algae cell walls, can be degraded by ulvan lyase through the β-elimination mechanism to obtain oligosaccharides exhibiting several good physiological activities. Only a few ulvan lyases have been characterized until now. This thesis explores the properties of a new polysaccharide lyase family 25 ulvan lyase TsUly25B from the marine bacterium Thalassomonas sp. LD5. Its protein molecular weight was 54.54 KDa, and it was most active under the conditions of 60 °C and pH 9.0. The Km and kcat values were 1.01 ± 0.05 mg/mL and 10.52 ± 0.28 s−1, respectively. TsUly25B was salt-tolerant and NaCl can significantly improve its thermal stability. Over 80% of activity can be preserved after being incubated at 30 °C for two days when the concentration of NaCl in the solution is above 1 M, while 60% can be preserved after incubation at 40 °C for 10 h with 2 M NaCl. TsUly25B adopted an endolytic manner to degrade ulvan polysaccharides, and the main end-products were unsaturated ulvan disaccharides and tetrasaccharides. In conclusion, our research enriches the ulvan lyase library and advances the utilization of ulvan lyases in further fundamental research as well as ulvan oligosaccharides production.

Highlights

IntroductionMarine seaweeds contribute much to photosynthesis on Earth
Paulert et al effects have shown that desulfated ulvan dimer can rides displayed more than ulvan polysaccharides in apple induce oxidative in dicotPaulert cells to et initiate a defense againstulvan pathogens mildewan[20]
We found that plots of the product (A235 ) against time multiplied by the initial enzyme concentration were superimposable in 5 min

Summary

Introduction

Marine seaweeds contribute much to photosynthesis on Earth. Marine algae, including red algae, brown algae, and green algae, have huge biomass and play a key role in marine ecosystems. Seaweeds with huge aquatic biomass and rapid growth velocity are getting more and more attention [1–3]. Polysaccharides, the main components of their biomass, can play a structural role in providing cell rigidity. Carrageenan is one of the cell wall polysaccharides of red algae. Alginate and ulvan are the most abundant cell wall polysaccharides of brown algae and green algae, respectively. There has been substantial research undertaken on the Carrageenan, alginate, and degrading enzymes

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