Application of alginate lyase and advantages of its gene cloning: A review

Alginate is a straight-chain polysaccharide composed of 1,4-glycosidic linkages between two uronic acids, β-D-mannuronic acid (M) and its C5 epimer, α-L-guluronic acid (G). It is primarily found in the cell walls and cytoplasm of brown algae, where it constitutes around 40% of their dry weight. Various techniques, including physical, chemical, and biological methods, are used to degrade alginate. Among these, biological degradation using alginate lyase is particularly effective. Alginate lyases are carbon-oxygen lyases (polysaccharide lyases) that break down 1,4-linked uronic acid chains via β-elimination, producing unsaturated oligosaccharides with terminal double bonds. Alginate lyase has important medical applications, such as in the treatment of cystic fibrosis. In such patients, Pseudomonas aeruginosa forms antibiotic-resistant biofilms, primarily composed of alginate. Alginate lyase helps disrupt these biofilms, improving antibiotic effectiveness. These enzymes are derived from a range of sources, including marine plants, mollusks, bacteria (especially marine types like Pseudomonas and Vibrio), fungi, and even viruses. Advancements in molecular biology have allowed for efficient gene cloning and expression of alginate lyase, particularly in Escherichia coli, a host known for its simple genetics, rapid growth, and high-level protein expression. Molecular cloning involves techniques used to create organisms that carry and replicate recombinant DNA, enabling large-scale enzyme production with high purity and activity.