[Culture optimization and characterization of an alginate-lyase from Pseudoalteromonas sp. LJ1]

The present work aimed to optimize the culture conditions to produce extracellular alginate-lyase by Pseudoalteromonas sp. LJ1.

A bacterial alginate-lyase producing strain LJ1 was isolated from Laminaria japonica by enrichment culture technique. The strain was identified based on phenotypic characters, fatty acid compositions and 16S rRNA gene sequencing. Culture conditions were optimized to produce the extracellular alginate-lyase by the single factor and orthogonal tests.

Strain LJ1 was identified as Pseudoalteromonas sp.. The optimal medium components were: sodium alginate 3 g/L, (NH4)2SO4 3 g/L, NaCl 20 g/L, KH2PO4 0.1 g/L, CaCl2 0.1 g/L; The optimal culture conditions were: 25 ml medium in 250 mL Erlenmeyer flask, inoculum's volume 3%, shaking speed of 150 r/min, initial pH 7.5, at 28 degrees C for 24 h. The enzyme exhibited maximal activity at pH 7.6, 40 degrees C and NaCl 0.3 mol/L. The enzyme activity was improved by Mg2+, and inhibited by Co2+ and Zn2+ at 1 mol/L.

Strain LJ1 was a novel alginate-lyase producing bacterium of Pseudoalteromonas.