[Effects of Three Industrial Organic Wastes as Amendments on Plant Growth and the Biochemical Properties of a Pb/Zn Mine Tailings].

A field trial was conducted in an abandoned Pb/Zn mine tailings to evaluate the effectiveness of three industrial wastes [sweet sorghum vinasse (SSV), medicinal herb residues (MHR) and spent mushroom compost (SMC)] as organic amendments on plant growth, soil nutrients and enzyme activities, and heavy metal concentrations in plant tissues and the mine tailings. (1) The main findings were as follows: (1) The mean concentrations of diethylene-triamine-pentaacetic acid (DTPA)-extractable Cd, Cu, Pb and Zn in SSV, MHR and SMC treatments decreased by 24.2%-27.3%, 45.7%-48.3%, 18.0%-20.9% and 10.1%-14.2% as compared to the control tailings. When compared to the control tailings, the mean values of organic matter, ammonium-N and available P in SSV, MHR and SMC treatments increased by 2.27-2.32, 12.4-12.8 and 4.04-4.74 times, respectively. Similarly, the addition of SSV, MHR and SMC significantly enhanced soil enzyme activities (dehydrogenase, beta-glucosidase, urease and phosphatase), being 5.51-6.37, 1.72-1.96, 6.32-6.62 and 2.35-2.62 times higher than those in the control tailings. (2) The application of these wastes promoted seed germination and seedling growth. The vegetation cover reached 84%, 79% and 86% at SSV, MHR and SMC subplots. For Lolium perenne and Cynodon dactylon, the addition of SSV, MHR and SMC led to significant increases in the shoot biomass yields with 4.2-5.6 and 15.7-17.3 times greater than those in the tailings. Moreover, the addition of SSV, MHR and SMC significantly reduced the concentrations of Cd, Cu, Pb and Zn in the shoots of L. perenne and C. dactylon in comparison with the control tailings. (3) Pearson's correlation coefficients showed that the vegetation cover and biomass were positively correlated with soil nutrient elements and enzyme activities. Significant negative correlations were observed between DTPA-extractable metal concentrations and vegetation cover and biomass. The metal concentrations in plants were positively correlated with soil DTPA-extractable metal concentrations and negatively correlated with soil nutrient elements and enzyme activities. The results obtained in this field study confirmed that the three organic-rich industrial wastes could be used as amendments for aided phytostabilization of some types of mine tailings.

Halobacillus hunanensis sp. nov., a moderately halophilic bacterium isolated from a subterranean brine.

A moderately halophilic, Gram-positive, catalase- and oxidase-positive, rod-shaped, aerobic bacterium, designated strain JSM 071077(T), was isolated from a subterranean brine sample collected from a salt mine in Hunan Province, China. Cells were motile by means of peritrichous flagella and formed ellipsoidal endospores lying in subterminal swollen sporangia. Strain JSM 071077(T) was able to grow with 2-25% (w/v) total salts (optimum, 5-10%), at pH 6.0-10.0 (optimum, pH 7.5) and 10-40 degrees C (optimum, 25-30 degrees C). meso-Diaminopimelic acid was present in the cell-wall peptidoglycan. The predominant menaquinone was MK-7, and the major cellular fatty acids were anteiso-C(15:0), anteiso-C(17:0) and iso-C(15:0). The genomic DNA G+C content was 41.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequence comparisons revealed that strain JSM 071077(T) should be assigned to the genus Halobacillus, being related most closely to the type strain of Halobacillus naozhouensis (98.8% sequence similarity), and the two strains formed a distinct subline in the neighbor-joining, minimum-evolution and maximum-parsimony phylogenetic trees. The sequence similarities between the novel isolate and the type strains of other recognized Halobacillus species ranged from 97.6% (with Halobacillus alkaliphilus) to 95.2% (with Halobacillus kuroshimensis). The results of the phylogenetic analyses, combined with DNA-DNA relatedness data, phenotypic characteristics and chemotaxonomic information, support that strain JSM 071077(T) represents a new species of the genus Halobacillus, for which the name Halobacillus hunanensis sp. nov. is proposed. The type strain is JSM 071077(T) (=DSM 21184(T) = KCTC 13235(T)).