Two Gram-positive, endospore-forming bacterial strains, CR-502^T and CR-14b, which produce surfactant molecules are described. Phenotypic tests and phylogenetic analyses showed these strains to be members of the genus Bacillus and related to the species Bacillus atrophaeus, Bacillus mojavensis, Bacillus subtilis, Bacillus vallismortis and Bacillus amyloliquefaciens, although they differ from these species in a number of phenotypic characteristics. DNA–DNA hybridization confirmed that they show less than 20 % hybridization with the above-mentioned species and therefore represent a novel species of Bacillus. The DNA G+C content is 46·4 mol% in strain CR-502^T and 46·1 mol% in strain CR-14b. The main fatty acids in strain CR-502^T are 15 : 0 anteiso (32·70 %), 15 : 0 iso (29·86 %) and 16 : 0 (13·41 %). The main quinone in strain CR-502^T is MK-7 (96·6 %). In the light of the polyphasic evidence gathered in this study, it is proposed that these strains be classified as a novel species of the genus Bacillus, with the name Bacillus velezensis sp. nov. The type strain (CR-502^T=CECT 5686^T=LMG 22478^T) was isolated from a brackish water sample taken from the river Vélez at Torredelmar in Málaga, southern Spain.

A formal proposal is made to rename the order Haloanaerobiales as Halanaerobiales, the family Haloanaerobiaceae as Halanaerobiaceae, the genera Haloanaerobium and Haloanaerobacter as Halanaerobium and Halanaerobacter, respectively, and to change the specific epithets of Halanaerobium acetoethylicum, Halanaerobacter lacunaris, Halocella cellulolytica and Halanaerobium chitinovorans to acetethylicum, lacunarum, cellulosilytica and chitinivorans, respectively. These changes are required in view of Rule 61, Appendix 9, of the Bacteriological Code.

Halomonas ventosaesp, nov. includes three moderately halophilic, exopolysaccharide-producing strains isolated from saline soils in Jaén (south-eastern Spain). These strains can grow anaerobically using either nitrate or nitrite as terminal electron acceptor and hydrolyse both tyrosine and phenylalanine. Their G+C content varies between 72·6 and 74·3 mol%. The affiliation of the isolates with the genusHalomonaswas confirmed by 16S rRNA gene sequence comparison. DNA–DNA hybridization shows 70·4–82·7 % relatedness among the three strains. Nevertheless, their relatedness is less than 43 % compared to related reference strains. The proposed type strain forHalomonas ventosaeis strain Al12^T(=CECT 5797^T=DSM 15911^T). It grows best at 8 % (w/v) sea salts and requires the presence of Na⁺. Its major fatty acids are 18 : 1ω7c, 16 : 0, 16 : 1ω7c, and 15 : 0 iso 2-OH. The predominant respiratory lipoquinone found in strain Al12^Tis ubiquinone with nine isoprene units (Q-9).

Given the major threat of phytopathogenic bacteria to food production and ecosystem stability worldwide, novel alternatives to conventional chemicals-based agricultural practices are needed to combat these bacteria. The objective of this study is to evaluate the ability of Pseudomonas segetis strain P6, which was isolated from the Salicornia europaea rhizosphere, to act as a potential biocontrol agent given its plant growth-promoting (PGP) and quorum quenching (QQ) activities. Seed biopriming and in vivo assays of tomato plants inoculated with strain P6 resulted in an increase in seedling height and weight. We detected QQ activity, involving enzymatic degradation of signal molecules in quorum sensing communication systems, against a broad range of N-acylhomoserine lactones (AHLs). HPLC-MRM data and phylogenetic analysis indicated that the QQ enzyme was an acylase. The QQ activity of strain P6 reduced soft rot symptoms caused by Dickeya solani, Pectobacterium atrosepticum and P. carotovorum on potato and carrot. In vivo assays showed that the PGP and QQ activities of strain P6 protect tomato plants against Pseudomonas syringae pv. tomato, indicating that strain P6 could have biotechnological applications. To our knowledge, this is the first report to show PGP and QQ activities in an indigenous Pseudomonas strain from Salicornia plants.

We have studied the extracellular polysaccharide (EPS) produced by the type strain, M8^T, of the halophilic bacterium Halomonas almeriensis, to ascertain whether it might have any biotechnological applications. All the cultural parameters tested influenced both bacterial growth and polysaccharide production. EPS production was mainly growth-associated and under optimum environmental and nutritional conditions M8^T excreted about 1.7 g of EPS per litre of culture medium (about 0.4 g of EPS per gram of dry cell weight). Analysis by anion-exchange chromatography and high-performance size-exclusion chromatography indicated that the exopolysaccharide was composed of two fractions, one of 6.3 × 10⁶ and another of 1.5 × 10⁴ Daltons. The monosaccharide composition of the high-molecular-weight fraction was mannose (72% w/w), glucose (27.5% w/w) and rhamnose (0.5% w/w). The low-molecular-weight fraction contained mannose (70% w/w) and glucose (30% w/w). The EPS has a substantial protein fraction (1.1% w/w) and was capable of emulsifying several hydrophobic substrates, a capacity presumably related to its protein content. The EPS produced solutions of low viscosity with pseudoplastic behaviour. It also had a high capacity for binding some cations. It contained considerable quantities of sulphates (1.4% w/w), an unusual feature in bacterial polysaccharides. All these characteristics render it potentially useful as a biological agent, bio-detoxifier and emulsifier.