Karakterisasi Resistensi dan Dekolorisasi Berbagai Pewarna Oleh Bakteri Indigen Indonesia Escherichia coli Strain CN5

The development of the textile industry in Indonesia is increasing the amount of dye waste produced. Copper is often a component of dyes, both of which harm aquatic ecosystems because they cannot be degraded. These problems can be overcome by bioremediation using bacteria isolated from polluted waters, called indigenous bacteria. It is hoped that indigenous bacteria can degrade textile waste and reduce copper toxicity in waters. This study aims to characterize, test resistance, and test the decolorization of the Indonesian indigenous bacterial isolate CN5 to dye and copper. There are 12 kinds of dyes used, namely: methylene blue, malachite green, congo red, mordant orange, reactive black, direct yellow, basic fuchsin, reactive orange, disperse orange, remasol red, wantex yellow, and wantex red. Resistance and decolorization tests on solid medium were carried out by growing bacterial cultures into luria bertani agar medium, each of which added a different type of dye. The dye concentrations tested were 100 ppm and 500 ppm. The ability to decolorize is known from the presence of a clear zone around the bacterial colony. The percentage of decolorization was tested using a spectrophotometer at a wavelength of 300-900 nanometers. Bacterial identification was carried out by 16S-rRNA sequencing. The results showed that CN5 isolates had a base similarity of 100% with Escherichia coli, so hereinafter referred to as E. coli strain CN5 could grow at 200 ppm and 500 ppm methylene blue, malachite green, congo red, mordant orange, reactive black, direct yellow, reactive orange, disperse orange, red remasol, yellow wantex, and red wantex but did not grow on fuchsin basic dye. Colonies of E. coli strain CN5 were only able to decolorize methylene blue with a concentration of 200 ppm and 500 ppm seen from the clear zone formed around the colony. The decolorization of methylene blue that occurred was 92.47%. The addition of copper reduced the decolorization ability to 75.59%. Based on the results of this study, it can be concluded that the E. coli strain CN5 has the potential to be used as a bioremediation agent for textile waste containing copper and methylene blue.Key words: dye; E. coli; copper; decolorization; resistan