Analysis of growth response and tolerance index of Glycine max (L.) Merr. under hexavalent chromium stress

Background: Metal pollution has become one of the most serious environmental problems due to various human activities. It can damage or alter the biosphere reducing the agricultural productivity and can affect both animals and humans.  Emission of various pollutants into the atmosphere has many harmful effects on plant growth. Rapid urbanization, unregulated industrialization, growing transport, metal plating and agricultural activities have created a problem of heavy metals contamination. Methods: A greenhouse experiment was conducted to determine the toxicity of chromium onGlycine max. Chromium concentration applied to G. max was managed as 0.5, 2.5, 5, 10, 25, 50 and 100 mg kg-1 for experimental period of 90 days. The phytotoxic effect of chromium metal was analyzed by studying seed germination, seedling vigor index, root and shoot length, root and shoot fresh and dry weights, chlorophyll content tolerance index.Results: The data presented in this study showed that chromium metal adversely affects the seedling vigor of G. max and significantly (p<0.05) reduces seed germination and growth. The toxic effect of chromium on the seeds increased with increasing the concentration of the metal. It was also found that high concentrations of chromium (50 and 100 mg kg-1) can completely inhibit the seed germination. Conclusion: The chromium metal is extremely toxic for seeds and young seedling of G. max at high concentrations. Moreover, G. max has little potential to counteract the deleterious effect of chromium metal in soil at aforementioned treatments. The results of the present study may help in better understanding of the mechanisms involved in pytoextraction

Biosorption of fluoride from aqueous solution by white—rot fungus Pleurotus eryngii ATCC 90888

AbstractIn present study the biosorption characteristics of fluoride anions from aqueous solution using white rot fungus (Pleurotus eryngii) were investigated as a function of pH, initial fluoride concentration, biosorbent dose, temperature, and contact time. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm of fluoride ions by P. eryngii biomass. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The monolayer biosorption capacity of P. eryngii biomass for fluoride ions was found to be 66.6mgg−1. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° indicate that the removal of fluoride ions by fungal biomass was endothermic and spontaneous in nature. Experimental data were also analyzed in terms of kinetic characteristics and it was found that biosorption process of fluoride ion followed well pseudo-second order model, where intra-particle diffusion was not the only rate-controlling step. The surface and sorption characteristics were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Fourier transform infrared (FTIR) spectrometry. In order to check the practical utility of the studied biosorbent, batch studies were carried out with fluoride contaminated water samples collected from a fluoride-endemic area. Eventually, this fungal biomass recommended to be used as a suitable, environment friendly and low cost biosorbent for removal of fluoride ion concentration to standard permissible limit

Isolation of Bacillus cereus from botanical soil and subsequent biodegradation of waste engine oil

Waste engine oil causes a vital environmental pollution when it spill during change and transportation and products of waste engine oil causes lethal effects to the living systems. Thus, abiotic and biotic approaches are being extensively used for removal of waste engine oil pollution. Therefore in present study, waste engine oil degradation was accomplished by a new bacterial culture, isolated from the soil by an enrichment technique. Morphological, biochemical and gene sequence analysis revealed that isolate was Bacillus cereus. Subsequently, biodegradation potential of B. cereus for waste engine oil was studied. Experimental variables, such as pH, substrate concentration, inoculum size, temperature and time on the biodegradation, were checked in mineral salt medium. The biodegradation efficiency of B. cereus was determined by gravimetry, UV–visible spectrophotometry and gas chromatography. In addition, waste engine oil was also characterized by GC–MS and FTIR for its major constituents, which showed total 38 components in waste engine oil, including hopanes, benzopyrene, long-chain aliphatic hydrocarbons, dibenzothiophenes, biphenyl and their derivatives. Results of successive biodegradation indicated that B. cereus was capable to degrade 1% of waste engine oil with 98.6% degradation potential at pH 7 within 20 days. Hence, B. cereus presents an innovative tool for removing the engine oil from the contaminated area