Zea mays, one of the most important cereals worldwide, is a plant not only with food and energy value, but also with phytoremediation potential. The use of plant growth promoting (PGP) rhizobacteria may constitute a biological alternative to increase crop yield and plant resistance to degraded environments. In search for PGP rhizobacteria strains, 6 bacterial isolates were isolated from a metal contaminated site, screened in vitro for their PGP characteristics and their effects on the growth of Z. mays were assessed. Isolates were identified as 3A10 T , ECP37 T , corresponding to Chryseobacterium palustre and Chryseobacterium humi, and 1ZP4, EC15, EC30 and 1C2, corresponding to strains within the genera Sphingobacterium, Bacillus, Achromobacter, and Ralstonia, respectively. All the bacterial isolates were shown to produce indole acetic acid, hydrogen cyanide and ammonia when tested in vitro for their plant growth promoting abilities, but only isolates 1C2, 1ZP4 and ECP37 T have shown siderophore production. Their further application in a greenhouse experiment using Z. mays indicated that plant traits such as root and shoot elongation and biomass production, and nutrient status, namely N and P levels, were influenced by the inoculation, with plants inoculated with 1C2 generally outperforming the other treatments. Two other bacterial isolates, 1ZP4 and ECP37 T also led to increased plant growth in the greenhouse. These 3 species, corresponding to strains within the genera Ralstonia (1C2), Sphingobacterium (1ZP4), and to a strain identified as C. humi (ECP37 T) can thus be potential agents to increase crop yield in maize plants.

A low-G+C-content Gram-positive bacterium, designated CV53 T , phylogenetically related to species of the genus Bacillus, was isolated from a highly alkaline non-saline groundwater environment (pH 11?4). This organism comprised rod-shaped cells, was aerobic, did not display spore formation, was catalase-and oxidase-negative, had an optimum growth temperature of 40 6C and had an optimum pH of approximately 7?0-8?5. Optimal growth was observed in the absence of NaCl, but growth did occur at NaCl concentrations up to 3?0 %. The strain possessed an A1c-type peptidoglycan cell wall and the major respiratory quinone was MK-7. The predominant fatty acids were anteiso-C 15 : 0 , iso-C 15 : 0 and anteiso-C 17 : 0 . The G+C content of the DNA was 43?1 mol%. Phylogenetic analyses of the 16S rRNA gene sequence revealed that the novel isolate is closely related to the type strain of Bacillus jeotgali, forming a coherent cluster supported by bootstrap analysis at a confidence level of 90 %. The pairwise similarity of the 16S rRNA gene sequences of the two strains is 97?7 %. On the basis of the phylogenetic analyses and the distinct phenotypic characteristics, strain CV53 T represents a novel species within the genus Bacillus, for which we propose the name Bacillus foraminis sp. nov. The type strain is CV53 T (=LMG 23174 T =CIP 108889 T ).Recently we investigated the bacterial diversity of a groundwater at Cabeço de Vide in southern Portugal. The ophiolite-like geological background of this aquifer and its chemical characteristics strongly suggest serpentinization. This groundwater, which has an outflow at a temperature of 20?5 uC, has a high level of alkalinity (pH 11?4) associated with an extremely low ionic concentration, with Ca 2+ and OH 2 as the major chemical constituents (Tiago et al., 2004).The majority of the populations recovered during this survey comprised high-G+C-content Gram-positive bacteria (Tiago et al., 2004). However, several low-G+C-content Gram-positive bacteria were also isolated; one strain, designated CV53 T , was of particular interest and was found to be phylogenetically related to the lineage containing the type strain of the species Bacillus jeotgali of the family Bacillaceae. In this study, we describe the morphological, physiological, chemotaxonomic and phylogenetic characteristics of strain CV53 T . On the basis of our results we propose that strain CV53 T represents a novel species of the genus Bacillus.Strain CV53 T was isolated from a non-saline alkaline groundwater environment by using alkaline buffered medium 2 (ABM2), adjusted to pH 8?5, at 37 u C, as described previously (Tiago et al., 2004). The isolate was routinely cultured under the same conditions and maintained at 270 u C in the same medium supplemented with 15 % glycerol. Unless otherwise stated, all morphological examinations and biochemical and tolerance tests were performed on this medium after 6 days incubation, as described previously (Tiago et al., 2005).The temperature range for growth of strain CV53 T was examined at tempe...

This study is focused on the diversity of bacterial communities from two series of horizontal subsurface flow constructed wetlands (CW) polishing high salinity tannery wastewater. Each series was planted with Arundo donax or Sarcocornia sp. in a substrate composed by expanded clay and sand. Chemical and biochemical oxygen demand removal efficiencies were similar in each series, varying between 58 and 67% (inlet COD 218 ± 28 mg L(-1)) and 60 and 77% (inlet BOD(5) 37 ± 6 mg L(-1)), respectively. High numbers of culturable bacteria were obtained from substrate and root samples - 5.75 × 10(6)-3.95 × 10(8) CFU g(-1) recovered on marine agar and 1.72 × 10(7)-8.46 × 10(8) CFU g(-1) on nutrient agar. Fifty bacterial isolates were retrieved from the CW, related phylogenetically to Firmicutes, Actinobacteria, Bacteroidetes, α-, β-, and γ-Proteobacteria. Changes in the bacterial communities, from roots and substrate of each series, related to the plant species, hydraulic loading rates and along CW operation were examined using denaturating gradient gel electrophoresis (DGGE). The clustering analysis suggested that a diverse and distinct bacterial community inhabits each series, which was related to the type of plant present in each CW.

Two Gram-staining-negative bacterial strains, designated 3A10 T and ECP37 T , were isolated from sediment samples collected from an industrially contaminated site in northern Portugal. These two organisms were rod-shaped, non-motile, aerobic, catalase-and oxidase-positive and formed yellow colonies. The predominant fatty acids were iso-C 15 : 0 , anteiso-C 15 : 0 , iso-C 17 : 1 v9c and iso-C 17 : 0 3-OH. The G+C content of the DNA of strains 3A10 T and ECP37 T was 43 and 34 mol%, respectively. The major isoprenoid quinone of the two strains was MK-6. 16S rRNA gene sequence analysis revealed that strains 3A10 T and ECP37 T were members of the family Flavobacteriaceae and were related phylogenetically to the genus Chryseobacterium. Strain 3A10 T showed 16S rRNA gene sequence similarity values of 97.2 and 96.6 % to the type strains of Chryseobacterium antarcticum and Chryseobacterium jeonii, respectively; strain ECP37 T showed 97.3 % similarity to the type strain of Chryseobacterium marinum. DNA-DNA hybridization experiments revealed levels of genomic relatedness of ,70 % between strains 3A10 T and ECP37 T and between these two strains and the type strains of C. marinum, C. antarcticum and C. jeonii, justifying their classification as representing two novel species of the genus Chryseobacterium. The names proposed for these organisms are Chryseobacterium palustre sp. nov. (type strain 3A10 T 5LMG 24685 T 5NBRC 104928 T ) and Chryseobacterium humi sp. nov. (type strain ECP37 T 5LMG 24684 T 5NBRC 104927 T ).