Stenotrophomonas maltophilia Having Decolorization Capability of Azo Dye Isolated from Anaerobic Sludge

摘要

Strain 5-8 was isolated from anaerobic sludge which was collected from a sewage treatment plant located at Shandong Province. Strain 5-8 has efficient ability to decolorize Fast Yellow2G. Fast Yellow2G was decolorized by more than 80 % in 48 h, and completely decolorized in 60 h. Strain 5-8 was observed to form yellow colored, smooth, circular, convex colonies of 5 mm diameter with entire margins on LB medium. Cells of strain 5-8 were observed to be gram-negative, aerobic, motile with a single polar flagellum and rod-shaped with dimensions of 0.3-0.4 × 0.6-1.5 μm. Growth was observed at 18-40 °C (optimum 35-37 °C), pH 6.0-9.0 (optimum pH 7.0-8.0) and with 0.5-5 % (w/v) NaCl (optimum 1 %). Neighbor-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain 5-8 belongs to the genus Stenotrophomonas, clustering coherently with the type strain of Stenotrophomonas maltophilia showing sequence similarity value of 99 %.