Natural rubber latex is one of the problems that raises the environmental concerns. In this study the degrading ability of Ficus elastica rubber latex by a bacterium strain ASU-03, isolated from Egyptian soil was assessed. The strain was able to produce clear zone around its colony on latex rubber containing medium and was identified by conventional methods as Streptomyces sp. Phylogenetic analysis of 16S rRNA (16S rRNA) and RNA polymerase β-subunit (rpoB) genes were applied. Results of the 16S rRNA gene analysis revealed that the strain was highly related to Streptomyces spp. (100% similarity), so the rpoB gene was partially sequenced to clarify the specific name of the isolate. Phylogenetic tree based on rpoB gene sequences indicated that …show more content…
10 ml of fuchsin reagent was added to the samples (50 μl of the NR dissolved in n-hexane) as described by [ 16 ]. The composition of the fuchsin reagent was prepared as follow: 2 g of fuchsin dissolved in 50 ml of glacial acetic acid plus 10 g of Na2S2O5 plus 100 ml of 0.1 N HCl + 50 ml of H2O [ 17 ]. Positive results are indicated by purple color at room temperature after 30 min. Scanning electron microscopy (SEM)
The morphological change during growth of the bacteria on NR was also assessed by SEM. The inoculated rubber samples as well as the control were fixed overnight in 5% glutaraldehyde, and then dried at 50 ºC. The samples were mounted on metal stubs and coated with gold and palladium (Jeol JFC1100E Iosputtering Device). Micrographs were taken by means of a Joel JSM-4500 LV electron microscope operating at 15 KV in Electron Microscopy Unit, Assiut University.
Phenotypic and molecular identification of the bacterial strain Phenotypic identification
The isolate was identified based on its morphological and biochemical properties using Bergey’s Manual of Systematic Bacteriology [