Papers by Keyword: Bacillus

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Authors: Iveta Štyriaková, Katarína Jablonovská, A. Mockovčiaková
Abstract: Quartz sands contain various iron and clay minerals which coat silicate grains or are impregnated in silicate matrix. Treatment by basin water bioleaching in combination with electromagnetic separation can substantially improve the quality of quartz sands. The purpose of this in-situ study was to evaluate the feasibility of using a biological basin treatment process to improve the quality of quartz sands. The environmental conditions involved the changes of climate temperature, using fresh surface water without disinfection, inhibition of algae and fungi, and promoting bacteria. Analyses of the solution phase were used to monitor the dissolution of iron during the bioleaching of the quartz sands and to optimize the in-situ conditions for the bacterial activity. The rate of iron dissolution varied with environmental conditions, with the addition of nitriloacetic acid (NTA)/l and organic feedstock in the form of molasses. Bacterial removal of clay and iron minerals can be used to expose the white surfaces of quartz grains. The quartz sands from the Šaštín deposit (Slovakia) were used in glass industry after decreasing the Fe content.
Authors: Wei Ling Zhang, Jian Fei Zhang, Zheng Li, Ji Xian Gong, Hui Ping Yang, Ke Ke Shang
Abstract: Biomodification of polyester film is a new field which can improve the surface property of material whithout environmental pollution and high energy consumption. Bacillus B-F which was isolated from waste water could biodegrade terephthalic acid. It was fermented and the broth was concentrated and used for surface process of polyester film. The modification lasted for 20 days. The surface property of the original and modified polyester film were tested. Contact angle examination showed that the hydrophilicity and surface free energy of the film was increased; XPS tests revealed the content of oxygen increased; FTIR showed that a small quantity of phenolic hydroxyl group appeared on the surface of the film; an oxygenase catalysed action might react at the surface of the film according to the degradation pathway of the simulacrum terephthalic acid.
Authors: Xiao Tao Yang, Jie Wang, Yong Hong Liao, Imdad Kaleem, Chun Li, Xiao Hong Zhou
Abstract: Food preservatives could cause a wide spectrum of antibacterial efficacies against different spoilage microbial species or strains; however, the mode of variation in antibacterial activities among and within species is still unclear which limits their effective applications in food preservation. In this study, ten thermoresistant spore-forming Bacillus strains as a typical spoilage microbial group were used to evaluate the variances of antibacterial activities of three chemical and three biological food preservatives among these species or strains by the statistical analysis of MIC using SAS 9.2 software. The biological preservatives exhibited much higher anti-bacillus activities compared to the chemical preservatives, and significant variances of MICs were observed among different Bacillus species for chemical preservatives while no variances were observed for biological preservatives. Variances of MICs among different strains in a species were not observed for both chemical and biological preservatives. The possible antibacterial mechanism has also been discussed to encounter food spoilage.
Authors: Katarína Jablonovská, Iveta Štyriaková
Abstract: This paper investigates Zn2+ and Cu2+ adsorption capability of bentonite and zeolite taken from the non-raw metallic deposits of Slovakia. Viable biomass of an Bacillus pumilus and Bacillus megaterium enhanced the efficiency of Zn2+ and Cu2+ adsorption from model solution. Initial concentration of Cu and Zn in model solutions initially containing 32.3 mg.Cu.L-1and 42.9 mg Zn.L-1 after six hours sorption and desorption at 25°C, it was observed that 1g bentonite whit bacteria inokulum was found to remove 0.195 mg Zn2+ and 0.17 mg Cu2+ from the solution and 1g zeolite was found to remove 0.088 Zn2+ and 0.051 Cu2+. The ability for Zn and Cu sorption was bentonite > zeolite. The adsorption of metal ions on bentonite and zeolite depends on pH. Between pH 4 and 6, the main mechanism is by ion exchange. In order to prevent contamination of subsoil and groundwater by leachates containing heavy metals, bentonite and zeolite are widely used as cost-effective treatments barriers. For this reason it is important to study the adsorption of metals by these materials.
Authors: Guo Yong Liu, Xing Bing Zhang, Ying Ping Huang, Xiao Ling Wang, Ya Ping Hu
Abstract: Aniline is considered as an environment hazard. Aniline-containing wastewater frequently has elevated salinity and high pH, which is generally not degraded by neutrophilic bacteria. The research explored the degradation ability of aniline by the novel isolated bacterial strain under alkaline and hyperhaline conditions. The strain was designated Bacillus sp. AN2 based on 16S rDNA sequence and Biolog Microstation Identification System. This strain had an unusually high salinity tolerance in minimal medium (0-6% NaCl, w/v). The optimal pH for microbial growth and aniline biodegradation was pH 9.0. For the initial concentrations of 200, 500, and 800 mgL-1, 95%, 74% and 62% of the aniline was degraded, respectively. The results suggest that the strain has potential for aniline degradation under alkaline and elevated salinity environmental conditions.
Authors: Iveta Štyriaková, Michal Lovás
Abstract: Bioleaching is technology applicable to iron extraction from low-grade non-metallic raw materials. Bioleaching of quartz sands and feldspars involves the action of heterotrophic bacteria. Impurities include fine – grained limonite, goethite, hematite or mica were removed by the reductive dissolution of Fe3+ in linked with the silicate mineral destruction. Heterotrophic bacteria produced organic acids that are able to solubilize Fe oxide and silicates but require organic carbon as a source of energy. Molasses is a relatively inexpensive carbon source used for various industrial fermentations and contains also other nutrients that accounted for the enhancement of iron dissolution in this study. The admixture of pigments in molasses coloured the samples, but the discoloration could be removed by the addition of NaClO following the bioleaching step. The feasibility of the bioleaching treatment has to be tested specifically to each type of silicate raw materials. The Fe content in the quartz sands and feldspar samples by the biological leaching decreased as much as 60% and by subsequent using of electromagnetic separation of feldspars, the decrease of Fe content in 74% was achieved. However, the application of magnetic separation of quartz sands after bioleaching resulted in total iron removal of 93 % and in such combined way prepared product contained 0.024 % of Fe2O3. Achieved results on iron removal point to the fact that combination of leaching and magnetic separation enables to obtain product usable in glass and ceramic industry.
Authors: Yu Ying Sun, Shu Jun Wang, Ji Quan Zhang
Abstract: In this work, we report the characterization of a chitosanase-producing bacterium isolated from soil. This strain was grouped under the genus Bacillus by virtue of its morphological, physiological properties and 16S rDNA gene sequence and named it Bacillus sp. S-1. According to the information of chitosanase full-length sequences deposited in NCBI, a pair of degenerated primes was designed and a partial sequence of chitosanase gene was obtained by polymerase chain reaction (PCR) using Bacillus sp. S-1 genome DNA as the template. A genome walking library was constructed followed as the protocol provided by CLONTECH Company. The flanking sequences of the 5’ and 3’ terminal was obtained by genome walking method and two-step PCR technique. After overlapped and confirmed, the full-length sequence of chitosanase from Bacillus sp. S-1 was achieved and it contained 1362 bp coding 453 amino acids (accession number is EU924147). The predicted amino acid sequence was 96% similar to that of Bacillus cereus ATCC 14579 (accession number is NC_004722). The fusion protein containing BSCHITO was produced in Escherichia coli and purified using Ni-NTA affinity chromatography. The purified rBSCHITO degraded the chitosan (the degree of deacetylation of 99%) to produce mixture of chitooligosaccharides. The BSCHITO is thus an endo-chitosanase.
Authors: Iveta Štyriaková
Abstract: Ultra-fine iron particles are difficult to treat by conventional mineral processing methods. Thus bioleaching is an attractive alternative for effective removal of iron minerals. The removal of oxidic Fe-phases from industrial silicates via bioleaching needs to be optimized with regard to the rate of iron reduction and dissolution. A new role for chelators as the low addition of AQDS or NTA during bacterial quality improvement of non-metallics, resulted in stimulating of Fe dissolution under non-controlled anaerobic conditions. AQDS stimulated bacterial iron reduction and Fe2+ concentration in solution was higher than Fe3+. However, NTA non-stimulated iron reduction, but increased bacterial iron dissolution in form of Fe3+. Changes in iron removal from samples were used to assess the chelator effectiveness of the heterotrophic bioleaching process. Chelators might be added to iron-contaminated non-metallics during bioleaching processes for stimulation of rate of iron removal.
Authors: Zheng Yuan Zhang, Yu Hong Xie, Chen Wang, Yu Xi Ma, Xin Feng, Yan Hui Ge
Abstract: In order to reduce the production cost of Microbial Flocculation,this article uses the cheap straw-inorganic nitrogen medium,directly domesticated and screened out a stable and efficient microbial flocculant producing strain B-15,which has better flocculation on kaolin clay suspension system. Preliminary identify as bacillu, the strain produce flocculant has flocculating rate of 81.08% for suspension.
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