Dyes and copper are dangerous contaminants because they are toxic. Bioremediation using indigenous bacteria is the best solution to overcome water pollution. Copper resistant bacteria usually have resistance to dyes thereby helping the bioremediation of dye and copper wastes. This study aims to examine the ability of indigenous bacteria isolated from the Cisadane River, namely Klebsiella grimontii IrCis3, Shigella flexneri IrCis5, Enterobacter cloacae IrCis6, and Enterobacter cloacae IrCis9 in terms of resistance and ability to decolorize 12 textile dyes namely methylene blue, malachite green, congo red, mordant orange, reactive black, direct yellow, basic fuchsin, reactive orange, dispersed orange, remasol red, wantex yellow and wantex red. The results showed that Shigella flexneri IrCis5, Enterobacter cloacae IrCis6, and Enterobacter cloacae IrCis9 were resistant to all dye concentrations of 200 and 500 ppm except Klebsiella grimontii IrCis3 did not grow on malachite green and basic fuchsin at concentrations of 200 ppm and methylene blue, malachite green and basic fuchsin concentration of 500 ppm. Only Shigella flexneri IrCis5 has the ability to decolorize 200 ppm basic fuchsin up to 87.23% after 3 days of incubation. The addition of 3 mM CuSO4 reduced the ability to decolorize Shigella flexneri IrCis5 to 0.57%.

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; resistant

<p><em>Antioxidants are substances that mitigate the impacts of free radicals on the body, in which they can be extracted from plants. One common Indonesian plant that has a potential to be used as a source of antioxidants is the ambarella plant (Spondias dulcis). The aim of this research is to measure the antioxidant activity of ambarella leaf’s extract via response surface methodology to determine the optimum conditions required to facilitate maximum extraction. Ambarella leaves were dried and soaked in methanol by using various combinations of time, methanol concentration and solid:solvent ratio (SSR). Antioxidant activity was measured using the DPPH test. The Response Surface Methodology (RSM) was utilized to determine the optimum conditions. The obtained optimum conditions were 26.5 hours, 82.2% methanol and a solid:solvent ratio of 1:14.6. </em><em></em></p><p><strong>Bahasa Indonesia Abstract:</strong></p><p>Antioksidan adalah sejenis senyawa yang dapat meminimalkan pengaruh radikal bebas dalam tubuh, dimana senyawa tersebut dapat diekstraksi dari tanaman. Salah satu tanaman di Indonesia yang memiliki potensi digunakan sebagai sumber antioksidan adalah kedondong (<em>Spondias</em> <em>dulcis</em>). Tujuan penelitian ini adalah untuk mengukur aktivitas antioksidan ekstrak daun kedondong, serta menemukan kondisi yang optimum untuk ekstraksi daun kedondong dengan menggunakan <em>response surface methodology</em>. Daun kedondong dikeringkan lalu dimaserasi menggunakan berbagai kombinasi parameter waktu, konsentrasi pelarut metanol, dan <em>solid:solvent ratio </em>(SSR). Aktivitas antioksidan ekstrak lalu diukur menggunakan uji DPPH. <em>Response Surface Methodology </em>(RSM) digunakan untuk menemukan kondisi yang optimum. Kondisi maserasi yang optimum adalah 26,5 jam, konsentrasi pelarut metanol 82,2% dan SSR 1:14,6.</p><p><strong><br /></strong></p>