Experimental study demonstrates petroleum hydrocarbon breakdown and reduced phytotoxicity in tomato plants, indicating potential for sustainable soil bioremediation.
Key Points
To evaluate the catalytic activity, soil persistence, and remediation efficacy of Bacillus subtilis α-amylase in degrading petroleum hydrocarbons and mitigating plant toxicity.
Characterized α-amylase kinetics across temperature and pH gradients using starch hydrolysis assays, DNS analysis, and thin-layer chromatography.
Tracked hydrocarbon breakdown and enzyme stability in contaminated soils over 30 days via FTIR spectroscopy and thin-layer chromatography.
Conducted 30-day pot experiments with tomato (Solanum lycopersicum) to measure root/shoot growth, oxidative stress markers, and antioxidant enzyme activity.
Purified α-amylase exhibited optimal catalytic activity at 37 °C and pH 7.0 (73.2 ± 0.8 U/mg protein, activation energy 25.6 kJ/mol) and persisted in soil through Day 30.
Enzyme treatment accelerated aliphatic hydrocarbon degradation and increased tomato shoot and root growth by 23.7% and 13.1%, mitigating petroleum-induced growth inhibition by 40% to 70%.
Phytotoxicity was markedly alleviated, evidenced by a drop in tissue hydrogen peroxide from 5.0 ± 0.3 to 3.0 ± 0.2 µmol/g FW alongside normalized proline levels and elevated antioxidant enzyme defenses.