Bioprospects of Tree Species in Bioremediation of Bauxite Residue

Abstract

Red mud or bauxite residue is a highly alkaline toxic by-product that is generated during the production of aluminum by Bayer’s process. Around 1.5 tons of bauxite residues are produced for generating 1 ton of alumina. The toxicity of bauxite residue is a major catastrophe due to its disposal management as it limits the growth of plant species because of high alkalinity and salinity. In the present study, bioprospects carried through the cyanobacterial strains (viz. Phormidium and Oscillatoria) with the planting of tree species have potentially shown successful outputs on the physical and chemical attributes of bauxite residue. The cyanobacterial strains were combined along with the microbial cultures of VAM (vesicular arbuscular mycorrhiza) and PSB (phosphate solubilizing bacteria) to enhance root length, leaf area, fresh and dry weight of shoot and root, plant height, and chlorophyll content. The inoculated seeds of a few plant species namely, Siamese cassia, Acacia auriculiformis A. Cunn. ex. Benth., Dalbergia sissoo Roxb. Ex DC., Pithecellobium dulce (Roxb.)., and Prosopis juliflora var. juliflora were raised to study the effect of bioremediation of bauxite residue for revegetation. Further, we also found that S. cassia, A. auriculiformis, D. sissoo, P. dulce, and P. juliflora var. juliflora thrived well on the amended bauxite residue with other useful inoculums.