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<p>Effluent discharge from dye-using industries like the textile, leather, food processing, cosmetics, paper, and related industries remains an emerging concern for the environment and public health. This study evaluates the efficiency of manganese peroxidase (MnP) produced by <i>Pseudomonas aeruginosa</i> (MF14446.1) and <i>Enterobacter roggenkampii</i> (CP033800.1) to detoxify and degrade Malachite green (MG) dye. Bacteria isolates were characterized using 16&#xa0;S rDNA. MnP activities of the crude enzymes obtained from the freeze-dried supernatants of the bacteria cultures were confirmed by the ability to oxidize NAD(P)H in the absence of H<sub>2</sub>O<sub>2</sub>. The enzymes’ optimal temperature, pH, incubation period, H<sub>2</sub>O<sub>2</sub>, and enzyme concentration required to decolourise the dye were investigated. The Michaelis-Menten model equation was used to obtain the enzyme kinetics (Vmax, Km, and the turnover number, kcat value (as Vmax/enzyme protein concentration). The efficiency of the degradation was evaluated by the toxicity of the degraded (treated) and untreated dyes on the growth of two Gram-positive (<i>Bacillus cereus</i> ATCC 14579 and <i>Staphylococcus aureus</i> LCT-SA112) and two Gram-negative (<i>Proteus mirabilis</i> H14320 and <i>Escherichia coli</i> ATCC 9637) bacteria. The crude enzymes of both <i>E. roggenkampii</i> and <i>P. aeruginosa</i> were found to be most efficient at the enzyme concentration of 20–50&#xa0;mg/ml, with a pH range of 5–7, requiring dye concentration of 100–200&#xa0;mg/l. Optima temperatures ranged between 30 and 40&#xa0;°C, and about 56–70% of the dye were decolourised within 100&#xa0;min in the proximity of 0.25–1.5 mM H<sub>2</sub>O<sub>2</sub>. <i>P. aeruginosa’s</i> crude extracts showed higher MnP activity (7.4 × 10<sup>− 3</sup> u/l) compared to the extract from <i>Enterobacter roggenkampii</i>: The kinetic parameters for <i>P. aeruginosa’s</i> crude extracts observed were Km (45.5 mM/min), Vmax (66.7 mM/L) and kcat (5 × 10<sup>− 3</sup>Mm/min). The treated dye supported the growth of gram-positive and gram-negative test organisms, which the untreated dye could not, deeming the enzymes to be both decolourizers and detoxifiers.</p>

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Biodegradation and detoxification of malachite green dye by crude manganese peroxidase produced by Pseudomonas aeruginosa MF14446.1 and Enterobacter roggenkampii CP033800.1

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  • 发表日期：

    2025年12月29日

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  • Bongekile Precious Ngcobo,
  • Foluso Oluwagbemiga Osunsanmi,
  • Albert Olufemi Ikhane,
  • Rebamang Anthony Mosa,
  • Andrew Rowland Opoku

摘要

Effluent discharge from dye-using industries like the textile, leather, food processing, cosmetics, paper, and related industries remains an emerging concern for the environment and public health. This study evaluates the efficiency of manganese peroxidase (MnP) produced by Pseudomonas aeruginosa (MF14446.1) and Enterobacter roggenkampii (CP033800.1) to detoxify and degrade Malachite green (MG) dye. Bacteria isolates were characterized using 16 S rDNA. MnP activities of the crude enzymes obtained from the freeze-dried supernatants of the bacteria cultures were confirmed by the ability to oxidize NAD(P)H in the absence of H2O2. The enzymes’ optimal temperature, pH, incubation period, H2O2, and enzyme concentration required to decolourise the dye were investigated. The Michaelis-Menten model equation was used to obtain the enzyme kinetics (Vmax, Km, and the turnover number, kcat value (as Vmax/enzyme protein concentration). The efficiency of the degradation was evaluated by the toxicity of the degraded (treated) and untreated dyes on the growth of two Gram-positive (Bacillus cereus ATCC 14579 and Staphylococcus aureus LCT-SA112) and two Gram-negative (Proteus mirabilis H14320 and Escherichia coli ATCC 9637) bacteria. The crude enzymes of both E. roggenkampii and P. aeruginosa were found to be most efficient at the enzyme concentration of 20–50 mg/ml, with a pH range of 5–7, requiring dye concentration of 100–200 mg/l. Optima temperatures ranged between 30 and 40 °C, and about 56–70% of the dye were decolourised within 100 min in the proximity of 0.25–1.5 mM H2O2. P. aeruginosa’s crude extracts showed higher MnP activity (7.4 × 10− 3 u/l) compared to the extract from Enterobacter roggenkampii: The kinetic parameters for P. aeruginosa’s crude extracts observed were Km (45.5 mM/min), Vmax (66.7 mM/L) and kcat (5 × 10− 3Mm/min). The treated dye supported the growth of gram-positive and gram-negative test organisms, which the untreated dye could not, deeming the enzymes to be both decolourizers and detoxifiers.