Semiconductor-Microbial Mechanism of Selective Dissolution of Chalcocite in Bioleaching.

Chalcocite-dominant secondary copper ore with a high pyrite content had a rapidly increased iron concentration in the middle and later periods of bioleaching, which increased the difficulty of separating copper and iron ions in the leaching solution. In the two aspects of microbial community succession and energy band theory, the selective dissolution mechanism of chalcocite in this type of copper ore was analyzed and illustrated using experiments and first-principles calculations. The results showed that controlling the solution potential at a lower level was beneficial to the selective leaching of chalcocite, while bacteria promoted the leaching of pyrite and chalcocite simultaneously by oxidizing Fe to Fe in the solution.

Isolation of phosphate-solubilizing fungi from phosphate mines and their effect on wheat seedling growth.

Three phosphate-solubilizing fungi, identified as Penicillium expansum, Mucor ramosissimus, and Candida krissii, were isolated from phosphate mines (Hubei, People's Republic of China) and characterized. All the isolates demonstrated diverse levels of phosphate-solubilizing capability in National Botanical Research Institute's phosphate growth medium containing rock phosphate as sole phosphate source. Acidification of culture medium seemed to be the main mechanism for rock phosphate solubilization.

Bacterial diversity based on 16S rRNA and gyrB genes at Yinshan mine, China.

The diversity of bacterial communities at three sites impacted by acid mine drainage (AMD) from the Yinshan Mine in China was studied using comparative sequence analysis of two molecular markers, the 16S rRNA and gyrB genes. The phylogenetic analyses retrieved sequences from six classes of bacteria, Nitrospira, Alphaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Acidobacteria, and Actinobacteria, as well as sequences related to the plastid of the cyanobacterium Cyanidium acidocaldarium and also some unknown bacteria. The results of phylogenetic analyses based on gyrB and 16S rRNA were compared.

Molecular diversity of 16S rRNA and gyrB genes in copper mines.

The molecular diversities of the microbial communities from four sites impacted by acid mine drainage (AMD) at Dexing Copper Mine in Jiangxi province of China were studied using 16S rRNA sequences and gyrB sequences. Of the four sampled sites, each habitat exhibited distinct geochemical characteristics and the sites were linked geographically allowing us to correlate microbial community structure to geochemical characteristics. In the present study, we examined the molecular diversity of 16S rRNA and gyrB genes from water at these sites using a PCR-based cloning approach.

Development and evaluation of 50-mer oligonucleotide arrays for detecting microbial populations in Acid Mine Drainages and bioleaching systems.

To effectively monitor microbial populations in acidic environments and bioleaching systems, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the known genes associated with the acidophiles. This array contained 1,072 probes in which there were 571 related to 16S rRNA and 501 related to functional genes. The functional genes in the microarray were involved in carbon metabolism (158), nitrogen metabolism (72), sulfur metabolism (39), iron metabolism (68), DNA replication and repair (97), metal-resistance (27), membrane-relate gene (16), transposon (13) and IST sequence (11).

[Study on the application of absorption spectrum to the treatment of landfill leachate by membrane technology].

Molecular weight (MW) distributions of organics in the Bei Shenshu landfill leachate and their permeation from membranes were determined and studied by absorption spectrum, and the removal rates of organics with various molecular weight were measured. A new FTIR preparation method of wastewater sample used in the determination of landfill leachate was proposed in the present paper. The results showed that the aromatics in landfill leachate were mainly related to the organics with MW < 2 500, whereas the distribution of total organics was dispersal comparatively.

Molecular cloning and characterization of a novel human C4orf13 gene, tentatively a member of the sodium bile acid cotransporter family.

By large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a novel human cDNA (C4orf13). This cDNA is 2706 bp in length, encoding a 340-amino-acid polypeptide that contains a typical SBF (sodium bile acid cotransporter family) domain and ten possible transmembrane segments. The putative protein C4orf13 shows high similarity with its orthologs in Mus musculus and Xenopus laevis.

Crystallization of oxytetracycline from fermentation waste liquor: influence of biopolymer impurities.

Organic impurities in the fermentation broth of antibiotic production impose great difficulties in the crystallization and recovery of antibiotics from the concentrated waste liquor. In the present laboratory study, the inhibitory effect of biopolymers on antibiotic crystallization was investigated using oxytetracycline (OTC) as the model antibiotic. Organic impurities separated from actual OTC fermentation waste liquor by ultrafiltration were dosed into a pure OTC solution at various concentrations.

[Nutrient balance and mechanism of biological degradation of oil].

This paper studied the nutrient balance and mechanism for enhancing the bioremediation of petroleum contaminated soils by the bio-slurry method. Oil degrading strains isolated and screened from Liaohe oil field was used. The results show that the suitable weight ratio of N and P element in the nutrient is 5.

Theoretical study of the surface energy and electronic structure of pyrite FeS2 (100) using a total-energy pseudopotential method, CASTEP.

The geometric and electronic structures of FeS(2) (100) surface have been studied by a quantum-mechanical calculation using a total-energy pseudopotential code, CASTEP. The (100) surface is very stable and does not give any significant geometric relaxation. The electronic structure of FeS(2) (100) surface is characterized by the appearance of new native surface states in the bulk band gap, which correspond to antibonding mixed Fea-Ssp(3) states.