Purification and partial characterization of oxalate oxidase from leaves of forage Sorghum (Sorghum vulgare var. KH-105) seedlings.

An oxalate oxidase was purified to apparent homogeneity from the leaves of 10-days old seedlings of forage Sorghum (Sorghum vulgare var. KH-105). The enzyme had a Mr of 124 kDa with two identical subunits, an optimum pH of 4.5, optimum temperature of 37°C and activation energy (Ea) of 2.0338 Kcal/mol. The rate of reaction was linear up to 7 min. Km value for oxalate was 0.22 mM. The enzyme was stimulated by Cu2+ and inhibited by EDTA, NaCN, diethyldithiocarbamate, na2SO4, but unaffected by NaCl at 0.1 mM concentration. Although the enzyme was stimulated by flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), UV and visible spectra of the enzyme did not match with that of a flavoprotein. The positive reaction of the enzyme with orcinol-H2SO4 reagent indicated its glycoprotein nature. The superiority of the purified enzyme over earlier reported oxalate oxidases for determination of urinary oxalate has been demonstrated.

Phytoremediation of toxic metals from soil and waste water.

Phytoremediation is an emerging technology, which uses plants and their associated rhizospheric microorganisms to remove pollutants from contaminated sites. This plant based technology has gained acceptance in the past ten years as a cheap, efficient and environment friendly technology especially for removing toxic metals. Plant based technologies for metal decontamination are extraction, volatilization, stabilization and rhizofiltration. Various soil and plant factors such as soil's physical and chemical properties, plant and microbial exudates, metal bioavailability plant's ability to uptake, accumulate, translocate, sequester and detoxify metal amounts for phytoremediation efficiency. Use of transgenics to enhance phytoremediation potential seems promising. Despite several advantages, phytoremediation has not yet become a commercially available technology Progress in the field is hindered by lack of understanding of complex interactions in the rhizosphere and plant based mechanisms which allow metal translocation and accumulation in plants. The review concludes with suggestions for future phytoremediation research.