Characterization of a New Intracellular Alginate Lyase with Metal Ions-Tolerant and pH-Stable Properties.

Yan Ma,Jie Li,Zhi-Peng Wang,Hai-Ying Wang,Xin-Yue Zhang,Feng-Biao Wang,Hao-Dong Ni

doi:10.3390/md18080416

Abstract

Alginate lyases play an important role in alginate oligosaccharides (AOS) preparation and brown seaweed processing. Many extracellular alginate lyases have been characterized to develop efficient degradation tools needed for industrial applications. However, few studies focusing on intracellular alginate lyases have been conducted. In this work, a novel intracellular alkaline alginate lyase Alyw202 from Vibrio sp. W2 was cloned, expressed and characterized. Secretory expression was performed in a food-grade host, Yarrowia lipolytica. Recombinant Alyw202 with a molecular weight of approximately 38.3 kDa exhibited the highest activity at 45 °C and more than 60% of the activity in a broad pH range of 3.0 to 10.0. Furthermore, Alyw202 showed remarkable metal ion-tolerance, NaCl independence and the capacity of degrading alginate into oligosaccharides of DP2-DP4. Due to the unique pH-stable and high salt-tolerant properties, Alyw202 has potential applications in the food and pharmaceutical industries.

Highlights

Alginate is a natural bioactive polysaccharide derived from the cell walls of widespread brown algae and several bacteria, which is composed of β-D-mannuronic acid (M) and α-L-guluronic acid (G) as monomeric units
Y. lipolytica URA- transformants were screened on YNB plates
Few studies focusing on intracellular alginate lyases have been conducted

Summary

Introduction

Alginate is a natural bioactive polysaccharide derived from the cell walls of widespread brown algae and several bacteria, which is composed of β-D-mannuronic acid (M) and α-L-guluronic acid (G) as monomeric units. The monomers of three kinds of different blocks are presented in the poly-β-D-mannuronic acid (polyM), poly-α-L-guluronic acid (polyG) and random heteropolymer (polyMG) [1]. The content ratio and arrangement of these monomers have a significant influence on biological properties of alginate, such as the gelatinization of fibers and the strengthening of cell walls [2]. AOS are the smaller bioactive units consisting of 3 to 25 monomers, which have versatile biological properties, including neuroprotective, antioxidant, anti-proliferative and antitumor capacities, as well as promoting plant growth [5,6,7,8]

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