Fig. 1

Degradation of kelp (Laminaria japonica) thallus fragments and polysaccharide substrates by strain ALW1 in kelp medium. A Kelp inoculated with the ALW1 cells. B Uninoculated kelp. C Micrograph of kelp cells inoculated with ALW1 strain and incubated at 30℃ at 80 rotation speed for 72 h, and kelp cells dispersed in the medium. D Micrograph of kelp cells in the culture medium without ALW1 strain and incubated at 30℃ with stirring at 80 rpm for 72 h, and the kelp cells were still neatly arranged. E Growth of strain ALW1 in L. japonica medium at 30 °C with stirring at 80 rpm for 72 h. F Extracellular polysaccharide-degrading enzymes’ activities. Enzyme activity analysis included alginate lyase, laminarinase, fucoidanase and cellulase assays. All the above enzyme activities were measured after ALW1 strain was inoculated in kelp medium and incubated at 30℃ with stirring at 80 rpm for 72 h. Data are presented as mean ± SD from three independent experiments