Biochar: Acinetobacter driven rhizoremediation of arsenic contaminated soil

Arsenic accumulation is becoming a major pollutant fueled by natural and anthropogenic activities. Arsenic contamination degrades the soil fertility and make it unsuitable for plants growth. Various physical and chemical solutions can be used to decontaminate the soil but these solutions have many limitations. Rhizoremediation along biochar, a potential strategy to treat the arsenic contaminated soil and biochar also improves the soil nutrient content. Therefore, this research focused on mitigating arsenic toxicity via the arsenic-tolerant Acinetobacter in combination with biochar. Arsenic tolerant bacteria was isolated from arsenic contaminated soil and identified as Acinetobacter. Biochar was prepared from the wood shaving of Cedrus deodara. A pot experiment was designed to check the rhizoremediation potential of biochar and Acinetobacter in the rhizosphere of Spinach. It is the first study to evaluate the potential of Acinetobacter and the biochar on the nutritional and arsenic accumulation in spinach. The collection of soil samples for the isolation of bacterial strains was done from the arsenic-affected site and the preparation of biochar was done using the wood shaving of Cedrus deodara. A pot experiment was conducted to figure out the potential of isolated bacterial strains and biochar individually as well as synergistically. The co-application of Acinetobacter and biochar improved spinach's morphological (shoot length 22%, root length 24%), physiological (chlorophyll 22%) and biochemical (proline 24%, soluble sugar 30%) attributes in arsenic contaminated soil. Both biochar and Acinetobacter also increase enzymatic and non-enzymatic content in plant. Arsenic content of soil decreased by 43% in root and 47% in shoot with co-application of biochar and Acinetobacter. Rhizoremediation potential of Acinetobacter and biochar in the plant rhizosphere to reduce the arsenic content considered to be a promising strategy for heavy metal remediation in soil.