Isolation and Characterization of Potential Bacteria with the Ability to Degrade Congo Red Dye

摘要

Bacterial isolates, which are able to degrade the azo textile dye Congo Red, have been isolated from Bantar Gebang Landfills-Bekasi and Citarum river, West Java. The initial screening using Zhou-Zimmerman medium which contains 50 ppm Congo Red yielded in 6 isolates (D2, Il, 14, L2B, L2C, and M) were able to degrade the dye. Selection for the best isolate using Bushnell-Haas medium showed that isolates L2C was able to degrade up to 98.5% of Congo Red within 3 days. The percentage of degradation was measured using Spectrophotometer at X 490 nm. Assessment of biodegradation profile of L2C at 500 ppm, 700 ppm and 1000 ppm of Congo Red showed that in 7 days, the isolates degraded the dye solution by 96.7%, 97.7% and 82.6%, respectively. The degrading rate of the re-isolated L2C cells at 1000 ppm of Congo Red increased up to 97.8% in 7 days when the cells were adapted into the Congo Red dye. Phytotoxicity test for germination using corn seed (Zea mays) showed that the toxicity of filtrate was slightly lower (50%) compared to the Congo Red 1000 ppm solution that is used as a control (67%). Molecular identification based on sequence 16S rRNA gene identified isolate L2C as Enterococcus faecalis.