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Aims: The Algerian coastline is exposed to several types of pollution, including hydrocarbons. The aim of this work was to isolate oil‐degrading bacteria and to explore the intrinsic bioremediation potential of part of its contaminated harbour. Methods and results: A collection of 119 strains, capable to grow on mineral medium supplemented with hydrocarbons, were obtained from polluted sediment and seawater collected from Sidi Fredj harbour (Algiers). Twenty‐three strains were selected for further studies. Sequencing of the 16S rRNA gene showed that most isolates belong to genera of hydrocarbonoclastic bacteria (Alcanivorax), generalist hydrocarbons degraders (Marinobacter, Pseudomonas, Gordonia, Halomonas, Erythrobacter and Brevibacterium) and other bacteria not known as hydrocarbon degraders (Xanthomarina) but were able to degrade hydrocarbons. Strains related to Marinobacter and Alcanivorax were frequently isolated from our samples and resulted the most effective in degrading crude oil. Screening of catabolic genes alkB and xylA revealed the presence of alkB gene in several bacterial strains; one isolate harboured both catabolic genes while other isolates carried none of the studied genes. However, they grew in the presence of crude oil implying the existence of other biodegradation pathways. Conclusions: The samples of seawater and sediment from the Algerian coast contain high level of hydrocarbon‐degrading bacteria that could be interesting and useful for future bioremediation purposes. Significance and Impact of the Study: This investigation demonstrates the diversity of hydrocarbon‐degrading bacteria from a marine‐contaminated area in Algeria, and their variable biodegradation abilities [ABSTRACT FROM AUTHOR]

Aims: Larvae of the red palm weevil (RPW) Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) feed inside palm stem tissues, making galleries and producing a wet fermenting frass. We characterized the culturable bacteria associated with frass produced by tunnelling larvae inside the Canary island date palms and investigated the role of frass and gut bacteria in plant polymers breakdown. Methods and Results: A culture-dependent method was used to isolate bacteria from frass and noninfested palm tissues. Bacterial isolates were grouped into operational taxonomic units based on polymorphisms in the ITS-PCR profiles, and representative isolates were identified by partial sequencing of the 16S rRNA gene. Frass bacteria were dominated by 2,3-butanediol fermenter Enterobacteriaceae. None of the bacterial isolates was able to degrade cellulose; however, cellulolytic and hemicellulolytic bacteria were isolated from the larval gut enrichment cultures. Conclusions: Frass bacteria are specifically associated with the RPW larvae and might play beneficial roles for RPW, other than nutritional, that deserve further investigations. Breakdown of plant polymers probably occurs inside the larvae digestive system. Significance and Impact of the Study: Frass and gut micro-organisms of R. ferrugineus should be included in studies of the interactions between RPW, its plant hosts, and its enemies. [ABSTRACT FROM AUTHOR]

Aims: To investigate the petroleum hydrocarbon (HC)-degrading potential of indigenous micro-organisms in a sandy Mediterranean coast, accidentally contaminated with petroleum-derived HCs. Methods and Results: Using culturable methods, a population of Gram-positive n-alkane degraders was detected in the contaminated soil. Five isolates, identified as one Nocardia, two Rhodococcus and two Gordonia strains, were able to degrade medium- and long-chain n-alkanes up to C36 as assessed by growth assays and gas chromatography-mass spectrometry analysis. Diverging alkane hydroxylase-encoding genes ( alkB) were detected by PCR, using degenerated primers, in all the strains; multiple sequences were obtained from the Nocardia strain, while only one alkB gene was detected in the Rhodococcus and Gordonia strains. The majority of the alkB sequences were related to Rhodococcus alkB2, but none was identical to it. Conclusions: Actinomycetes might have a key role in bioremediation of n-alkane-contaminated sites under dry, resource-limited conditions, such as those found in the Mediterranean shorelines. Significance and Impact of the Study: To our knowledge, this is the first study on the bioremediation potential in Mediterranean contaminated beaches. [ABSTRACT FROM AUTHOR]

Aims: The molecular diversity of 25 strains of rhizobia, isolated in Sicily from root nodules of the Mediterranean shrubby legume Spanish broom (Spartium junceum L.), is presented in relation to the known rhizobial reference strains. Methods and Results: Our approach to the study of the S. junceum rhizobial diversity combined the information given by the 16S and the intergenic spacer (IGS) 16S–23S rDNA polymorphic region by obtaining them in a single polymerase chain reaction (PCR) step. The PCR fragment size of the S. junceum isolates was 2400–2500 bp and that of the reference strains varied from 2400 in Bradyrhizobium strains to 2800 in Sinorhizobium strains. Inter- and intrageneric length variability was found among the reference strains. Restriction fragment length polymorphisms (RFLP) analysis allowed us to identify eight genotypes among the S. junceum rhizobia that were clustered into two groups, both related to the Bradyrhizobium lineage. Sequencing of representative strains of the two clusters confirmed these data. The 16S–IGS PCR–RFLP approach, when applied to rhizobial reference strains, allowed very close species (i.e. Rhizobium leguminosarum/R. tropici) to be separated with any of the three enzymes used; however, cluster analysis revealed inconsistencies with the 16S-based phylogenesis of rhizobia. Conclusions: Rhizobia nodulating S. junceum in the Mediterranean region belong to the Bradyrhizobium lineage. Our results confirm the resolution power of the 16S–23S rDNA in distinguishing among rhizobia genera and species, as well as the usefulness of the PCR–RFLP method applied to the entire 16S–IGS region for a rapid tracking of the known relatives of new isolates. Significance and Impact of the Study: The present paper is, to our knowledge, the first report on rhizobia nodulating a Mediterranean wild woody legume. [ABSTRACT FROM AUTHOR]