Novel insoluble dye-labeled substrates for screening inulin-degrading microorganisms

Inulin hydrogels were used to prepare insoluble colored substrates for screening of inulin-degrading microorganisms. Methycrylated inulin, synthesized with glycidyl methacrylate, was crossed-linked by free radical polymerization producing an insoluble hydrogel. The inulin hydrogels were colored with one of three covalent dyes (Reactive blue 4, Reactive orange 14, Reactive red 120). The efficacy of the colored inulin hydrogels was determined by comparing their performance to insoluble, colored amylose, xylan and HE-cellulose in screening assays. Novel substrates (alone or in combination with other insoluble colored substrates) were successfully used for screening inulin-degrading microorganisms from sludge samples. Selected strains were identified using 16S rDNA gene partial sequencing; all of them belong to the genus Bacillus.