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An extract of the indigenous plant jack bean (Canavalia ensiformis) was used to produce calcite, an effective biomaterial. The formation of calcite using this extract was compared, under stable conditions, to that using commercially available purified urease. Xray diffraction and scanning electron microscopy were employed to elucidate the mechanism of calcite formation from the crude plant extracts. The results revealed that urease in the jack bean crude extracts catalyzed the hydrolysis of urea in liquid-state cultures. The procedure described herein is a simple and useful method of calcite mineral precipitation that does not require cultivation of microorganisms or further purification of crude extracts. This study suggests that crude extracts of Canavalia ensiformis have the potential to be used in place of purified forms of urease during remediation of cracks and to increase the strength of materials. . "The transformation of vaterite to calcite: Effect of the conditions of the solutions in contact with the mineral phase.

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The biphenyl-degrading strain, Pseudomonas sp. KM-04, was isolated from polychlorinated biphenyls-contaminated soil sample obtained from the vicinity of a former coal mine. We herein report that strain KM-04 can use biphenyl as a sole carbon source, and resting cells convert biphenyl to its corresponding metabolic intermediates. Incubation of KM-04 with autoclaved mining-contaminated soil for 10 days in a slurry system reduced the levels of biphenyl and 2-chlorobiphenyl by 98.5 % and 82.3 %, respectively. Furthermore, treatment of a mine-soil microcosm with strain KM-04 for 15 days in a composting system under laboratory conditions reduced the levels of biphenyl and 2-chlorobiphenyl by 87.1 % and 68.7 %, respectively. These results suggest that KM-04 is a potential candidate for the biological removal of biphenyl and its chlorinated derivatives from polychlorinated biphenyl-contaminated mining areas.

Microbial changes in the characteristics of dissolved organic matter (DOM) and the subsequent effects on the conditional stability constants of copper were investigated using 14 day-incubations of Pony Lake fulvic acid (PLFA), Suwannee River fulvic acid (SRFA) and the mixtures of the humic substances and glucose. After incubation, dissolved organic carbon (DOC) concentrations were diminished, and specific UV absorbance values and DOC-normalized fluorescence intensities increased. The microbial changes were minimal for the samples contaning humic substances only whereas they were much pronounced for the mixtures with glucose. The extent of the changes increased with a higher content of glucose in the mixtures. The same trend was observed even for glucose solution. Our results suggest that labile organic moieties may be transformed into more chromophoric and humidified components by biodegradation. For the mixture samples, the copper binding stability constants did not change or even decreased after incubation. Therefore, microbially induced enrichment of the fulvic-and humic-like carbon structures in DOM appears to result in little change or the decrease of the copper binding coefficients.