Bacillus cihuensis sp. nov., isolated from rhizosphere soil of a plant in the Cihu area of Taiwan

A Gram-positive, moderately halotolerant, rod-shaped, spore forming bacterium, designated strain FJAT-14515^T was isolated from a soil sample in Cihu area, Taoyuan County, Taiwan. The strain grew at 10–35 °C (optimum at 30 °C), pH 5.7–9.0 (optimum at pH 7.0) and at salinities of 0–5 % (w/v) NaCl (optimum at 1 % w/v). The diagnostic diamino acid of the peptidoglycan of the isolated strain was meso-diaminopimelic acid and major respiratory isoprenoid quinone was MK-7. Major cellular fatty acids were anteiso-C_15:0 (40.6 %), iso-C_15:0 (20.7 %) and the DNA G+C content of strain FJAT-14515^T was 37.1 mol %. A phylogenetic analysis based on 16S rRNA gene sequences indicated that strain FJAT-14515^T belongs to the genus Bacillus, and was most closely related to the reference strains of Bacillus muralis DSM 16288^T (97.6 %) and Bacillus simplex DSM 1321^T (97.5 %). Levels of DNA–DNA relatedness between strain FJAT-14515^T and the reference strains of B. muralis DSM 16288^T and B. simplex DSM 1321^T were 27.9 % ± 3.32 and 44.1 % ± 0.57, respectively. Therefore, on the basis of phenotypic, chemotaxonomic and genotypic properties, strain FJAT-14515^T represents a novel species of the genus Bacillus, for which the name Bacillus cihuensis sp. nov. is proposed. The type strain is FJAT-14515^T (=DSM 25969^T = CGMCC 1.12697^T).     

Removal of benzene and toluene by carbonized bamboo materials modified with TiO2

Carbonized moso bamboo (Phyllostachys pubescens) was coated with TiO(2) nanoparticles to enhance its removal efficiency of harmful gases. Carbonized bamboo-TiO(2) composite (CBC) was prepared by heating mixtures of carbonized bamboo powder (CB) and TiO(2) nanoparticles, denoted as CBM, under nitrogen condition. TiO(2) nanoparticle and carbonized bamboo powder were mixed with the mass ratios of 1/1 and 2/1, respectively. At the same mass ratio of TiO(2) to CB, the benzene and toluene removal efficiencies follow the trend: CBC>CBM>CB, which is consistent with the amount of TiO(2) validated by elemental analysis. Sorption mechanism of benzene and toluene by CB, CBM and CBC might belong to hydrophobic-hydrophobic interaction, observed by depletion of untreated bamboo (UB) carbohydrates during carbonization. Sorption kinetics was further analyzed, and optimal correlation was found by fitting with the Elovich kinetic equation.     

Soil composition affects the nesting behavior of blue-tailed bee-eaters (Merops philippinus) on Kinmen Island

The blue-tailed bee-eater (Merops philippinus) is a summer migrant that breeds on Kinmen Island, located off the west coast of Taiwan, about 5 km from the southern coast of mainland China. The aim of this study was to investigate why blue-tailed bee-eaters build their nests in sandy loam and sandy clay loam, but not in clay loam. Soil chemical and physical properties, and mineralogical composition were measured for the different soil types. Clay loam had a significantly lower pH, Na, and base saturation than did sandy loam or sandy clay loam. Clay loam had a significantly higher N, cation-exchange capacity (CEC), K, and free iron (Fe_d) and aluminum oxide (Al_d) contents than the other soil types. Clay loam had significantly lower sand and higher clay content, and higher bulk density and penetration resistance than the other soil types. The correlation coefficients (r ²) between penetration resistance and Fe_d, Al_d, and clay contents were 0.997, 0.848, and 0.779, respectively. Soil strength and compaction are important criteria for bee-eaters nesting-site selection. The lower pH of clay loam would enhance the exchangeable Al and acidity, further increasing the soil aggregation. Thus, it might prevent the bee-eaters from excavating nesting burrows.     

Determination of low molecular weight dicarboxylic acids and organic functional groups in rhizosphere and bulk soils of Tsuga and Yushania in a temperate rain forest

Low molecular weight organic acids (LMWOAs) derived from root exudates, decomposing organic matter, and other sources are important ligands. The species of these LMWOAs in the Tsuga rhizosphere soil (TRS), and Yushania rhizosphere soil (YRS), and bulk soil (BS) from an alpine forest region were identified. LMWOA and organic functional groups were used to those fresh twigs and leaves, litters, and roots as comparison. The objectives of this study were to (i) develop a method that could be used to determine LMWOAs in soil solution by gas chromatography (GC), (ii) assess methods for processing LMWOAs in soil samples, and (iii) determine the relative proportions of organic carbon functional groups in the TRS, YRS and BS, and fresh plant materials with¹³C nuclear magnetic resonance (¹³C NMR) analysis. The proportion of organic acid contents followed the order of YRS > TRS > BS, and also showed significant differences (P < 0.05) from GC analysis. The amounts of malonic, fumaric and succinic acids in the YRS samples were greater than in the TRS and BS. Samples analyzed after 1 month of deep freeze storage (–24°C) showed no signs of decomposition. The proportion of organic functional groups in the rhizosphere and bulk soils quantified by ¹³C NMR analyses followed the general order: alkyl-C > O-alkyl-C > N-alkyl-C > acetal-C > aromatic-C > carboxylic-C > phenolic-C.     

Remediation of Arsenic-Contaminated Soil Using Alkaline Extractable Organic Carbon Solution Prepared from Wine-Processing Waste Sludge

Past studies have shown that dissolved organic carbon (DOC) washing can effectively remove heavy metals from contaminated soil. In this study, we used alkaline DOC solutions for remediation of arsenic (As)-contaminated soil (with an initial As concentration in the topsoil of 390 mg kg^?1). The removal of As and the change in soil nutrients during DOC washing were studied for 60 min at pH 10 with a 60:1 liquid/soil ratio (v/m). Approximately 88% of As was removed by washing the soil twice using a 3000 mg L^?1 DOC solution at 25°C. Following this treatment, the pH of the soil had increased from 5.6 to 9.2; organic carbon content had increased from 3.5% to 4.1%; cation exchange capacity, ammonium-N, and available phosphorus had increased to 2.3, 1.4, and 6.6 times their original levels, respectively; and exchangeable K, Na, Ca, and Mg had increased to 91, 6.1, 4.2, and 2.2 times their original levels, respectively. A sequential extraction investigation revealed that residual As and easily exchangeable As in the fraction were initially 10.2% and 9.2%, respectively, but that the former became the maximum remainder (64%) after the ultimate DOC washing.