**5.1 Enrichment cultures and streaking on MSM agar plates**

After preparing media, enrichment cultures were done where 2 ml of lake water was added into a test tube containing 8 ml of MSM prepared before and 0.1% of carbazole was also added as sole carbon source. The cultures are then sub cultured two times and color change was observed and compared with the control. Another test tube was also prepared but without any water samples as a control. **Table 6** shows change in color observed on first, second and third enrichment medium for the lake water sample collected from Unimas lake. In tube C, it could be observed major color change from cloudy to greenish yellow after three weeks. On the second and third enrichment the substrate residue become smooth and the color change to pale yellow compared to the control which is clear after two weeks.

**Control media Tube A**
