Bioremediation potential of Brevibacillus parabrevis AMB‐CD‐2 in spinach under lead toxicity

Abstract

AbstractThe present study was conducted to evaluate the impact of lead toxicity on the growth parameters of spinach and the performance of lead‐resistant bacterial isolates under lead stress conditions. Out of four bacterial isolates selected for this study, only two isolates AMB‐CD‐2 and AMB‐CD‐4 were selected based on their lead tolerance ability. A polybag experiment was conducted with six treatments and four replications in spinach. The treatments included T1 (RDF + control), T2 (lead acetate), T3 (AMB‐CD‐2 + lead), T4 (AMB‐CD‐4 + lead), T5 (AMB‐CD‐2), and T6 (AMB‐CD‐4). Results showed that lead contamination significantly decreased plant growth parameters, particularly in the treatment T2 (lead acetate) when compared with other treatments. Similarly, reduced uptake of nitrogen, phosphorus, and potassium (NPK) was recorded in T2. Inoculation with lead‐resistant bacteria, AMB‐CD‐2, significantly improved plant growth parameters (plant height, root fresh weight, shoot fresh weight, root dry weight, shoot dry weight, and root length). The uptake of NPK was higher in T5 (AMB‐CD‐2) in the absence of lead by approximately 0.81%, 0.37%, and 0.42% than in the control, respectively. Through atomic absorption spectrophotometer analysis, the lead concentration in treatment T2 (control) was about 3.20 mg/g while in treatment T3 (AMB‐CD‐2 + lead) it was about 1.32 ppm. The 16S rRNA gene sequencing revealed that AMB‐CD‐2 resembles Brevibacillus parabrevis. The results demonstrate that the lead‐resistant bacteria B. parabrevis AMB‐CD‐2 showed a significant lead reduction of approximately 58.75% compared to the control.