Bacterial diversity from benthic mats of Antarctic lakes as a source of new bioactive metabolites.

During the MICROMAT project, the bacterial diversity of microbial mats growing in the benthic environment of Antarctic lakes was accessed for the discovery of novel antibiotics. In all, 723 Antarctic heterotrophic bacteria belonging to novel and/or endemic taxa in the α-, β- and γ-subclasses of the Proteobacteria, the Bacteroidetes branch, and of the high and low percentage G+C Gram-positives, were isolated, cultivated in different media and at different temperatures, and then screened for the production of antimicrobial activities. A total of 6348 extracts were prepared by solid phase extraction of the culture broths or by biomass solvent extraction.

Biological denitrification in drinking water treatment using the seaweed Gracilaria verrucosa as carbon source and biofilm carrier.

Chemical and microbiological aspects were investigated with regard to biological denitrification of drinking water using the seaweed Gracilaria verrucosa as the carbon and energy substrate and as physical support for the microbial flora in semibatch, fixed-bed reactors. Complete removal of nitrate (100 mg/L) was readily achieved without accumulation of nitrite. Microbiological analysis indicated that the effluent of the reactor contained high numbers of bacteria (>10(6)/mL total count).

Reclassification of [Cytophaga] marinoflava Reichenbach 1989 as Leeuwenhoekiella marinoflava gen. nov., comb. nov. and description of Leeuwenhoekiella aequorea sp. nov.

Five heterotrophic, aerobic, halotolerant and pigmented bacterial strains with gliding motility were isolated from Antarctic sea water; one other isolate was collected from the sea urchin Strongylocentrotus intermedius in the Gulf of Peter the Great in the Sea of Japan. 16S rRNA gene sequence analysis indicated that the strains are members of the family Flavobacteriaceae, the nearest neighbour (with 97.1 % sequence similarity) being the misclassified species [Cytophaga] marinoflava.

Flavobacterium fryxellicola sp. nov. and Flavobacterium psychrolimnae sp. nov., novel psychrophilic bacteria isolated from microbial mats in Antarctic lakes.

Taxonomic studies were performed on seven strains isolated from microbial mats in Antarctic lakes of the McMurdo Dry Valleys. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains are related to the genus Flavobacterium; sequence similarity values with their nearest phylogenetic neighbours ranged from 97.0 to 98.

Algoriphagus antarcticus sp. nov., a novel psychrophile from microbial mats in Antarctic lakes.

A taxonomic study was performed on six strains isolated from microbial mats of lakes Reid, Fryxell and Ace in Antarctica. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belonged to the family 'Flexibacteraceae' and were closely related to the recently described genera Algoriphagus and Hongiella. The isolates were Gram-negative, chemoheterotrophic, aerobic, psychrophilic, orange-red-pigmented bacteria and their DNA G+C content ranged from 39.

Caenibacterium thermophilum is a later synonym of Schlegelella thermodepolymerans.

Recently, two strains of Schlegelella thermodepolymerans Elbanna et al. 2003 and an independently isolated bacterium, Caenibacterium thermophilum Manaia et al. 2003, were described in parallel as gen.

Glaciecola polaris sp. nov., a novel budding and prosthecate bacterium from the Arctic Ocean, and emended description of the genus Glaciecola.

Four strains of cold-adapted, strictly aerobic and facultative oligotrophic bacteria were isolated from polar seas and investigated using a polyphasic taxonomic approach. Two strains (LMG 21857T and LMG 21854) derive from Arctic sea water whereas the other two strains (LMG 21855 and LMG 21858) were isolated from Antarctic sea water. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belong to the gamma-subclass of the Proteobacteria and are related to the genus Glaciecola, with 98.

Loktanella salsilacus gen. nov., sp. nov., Loktanella fryxellensis sp. nov. and Loktanella vestfoldensis sp. nov., new members of the Rhodobacter group, isolated from microbial mats in Antarctic lakes.

A taxonomic study was performed on 26 strains isolated from microbial mats in Antarctic lakes of the Vestfold Hills and the McMurdo Dry Valleys. Phylogenetic analysis based on 16S rRNA gene sequences placed these strains within the Rhodobacter group of the alpha-subclass of the Proteobacteria. Sequence similarity values for the strains with their nearest phylogenetic neighbours (Jannaschia, Octadecabacter and Ketogulonicigenium) ranged between 94.

Alteromonas stellipolaris sp. nov., a novel, budding, prosthecate bacterium from Antarctic seas, and emended description of the genus Alteromonas.

Seven novel, cold-adapted, strictly aerobic, facultatively oligotrophic strains, isolated from Antarctic sea water, were investigated by using a polyphasic taxonomic approach. The isolates were Gram-negative, chemoheterotrophic, motile, rod-shaped cells that were psychrotolerant and moderately halophilic. Buds were produced on mother and daughter cells and on prosthecae.

Gillisia limnaea gen. nov., sp. nov., a new member of the family Flavobacteriaceae isolated from a microbial mat in Lake Fryxell, Antarctica.

A taxonomic study was performed on three strains isolated from microbial mats in Lake Fryxell, McMurdo Dry Valleys, Antarctica. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belong to the family Flavobacteriaceae, in which they form a distinct lineage. The isolates are Gram-negative, chemoheterotrophic, aerobic, rod-shaped cells.

Biodegradation of chemically modified flax fibers in soil and in vitro with selected bacteria.

The extent and rate of degradation of flax (Linum usitatissimum) fibers, both in the native state and after surface chemical modification (acetylation or poly(ethylene glycol), PEG, grafting), was investigated under laboratory conditions in two different biodegrading environments. Degradation of the fibers under aerobic conditions by the action of the microorganisms present in soil is assessed with the ASTM 5988-96 method by monitoring carbon dioxide evolution. In vitro biodegradation experiments were carried out by exposing the fibers to a pure culture of Cellvibrio fibrovorans bacteria and measuring the mass loss as a function of time.

Flavobacterium degerlachei sp. nov., Flavobacterium frigoris sp. nov. and Flavobacterium micromati sp. nov., novel psychrophilic bacteria isolated from microbial mats in Antarctic lakes.

Taxonomic studies were performed on 36 strains that were isolated from microbial mats in Antarctic lakes of the Vestfold Hills, the Larsemann Hills and the McMurdo Dry Valleys. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains are related to members of the genus Flavobacterium; sequence similarity values with their nearest phylogenetic neighbours ranged from 96.8 to 98.

Thermomonas fusca sp. nov. and Thermomonas brevis sp. nov., two mesophilic species isolated from a denitrification reactor with poly(epsilon-caprolactone) plastic granules as fixed bed, and emended description of the genus Thermomonas.

Previously, 22 aerobic Gram-negative bacteria were isolated from biofilms growing on granules of the synthetic polyester poly(epsilon-caprolactone); the granules were used as a fixed bed in a denitrification reactor. All the strains showed similar fatty acid profiles. The 16S rRNA gene sequences of five strains were phylogenetically related to Thermomonas spp.

Flavobacterium gelidilacus sp. nov., isolated from microbial mats in Antarctic lakes.

Twenty-two isolates from microbial mats in eastern Antarctic lakes showed similar fatty acid compositions and were investigated further using a polyphasic taxonomic approach. Repetitive extragenic palindromic DNA-PCR fingerprinting of the 22 strains revealed three groups, and DNA-DNA hybridizations between representatives showed more than 87 % DNA-DNA reassociation with each other. 16S rRNA gene sequence analysis placed two representative strains, LMG 21477(T) and LMG 21619, within the genus Flavobacterium, with 95.

Schlegelella thermodepolymerans gen. nov., sp. nov., a novel thermophilic bacterium that degrades poly(3-hydroxybutyrate-co-3-mercaptopropionate).

A novel thermophilic bacterium, strain K14T, capable of degrading poly(3-hydroxybutyrate) as well as copolymers containing 3-hydroxybutyrate and 3-mercaptopropionate linked by thioester bonds, was isolated. 16S rDNA sequence analysis showed that strain DhA-71, a dehydroabietic acid-degrading bacterium, was the nearest phylogenetic neighbour and that both strains should be placed as members of a newly created genus, Schlegelella gen. nov.

Bioremediation of diesel oil-contaminated soil by composting with biowaste.

Soil spiked with diesel oil was mixed with biowaste (vegetable, fruit and garden waste) at a 1:10 ratio (fresh weight) and composted in a monitored composting bin system for 12 weeks. Pure biowaste was composted in parallel. In order to discern the temperature effect from the additional biowaste effect on diesel degradation, one recipient with contaminated soil was hold at room temperature, while another was kept at the actual composting temperature.

Taxonomic study of Cellvibrio strains and description of Cellvibrio ostraviensis sp. nov., Cellvibrio fibrivorans sp. nov. and Cellvibrio gandavensis sp. nov.

Thirty-one cellulolytic bacterial isolates from soils that were phenotypically very similar and phylogenetically highly related to Cellvibrio strains were further characterized using a polyphasic taxonomic approach. By using repetitive extragenic palindromic DNA-PCR fingerprinting, six different fingerprints could be recognized among the isolates. Representative strains and four reference strains of the genus Cellvibrio were used for DNA-DNA hybridization, which yielded eight DNA hybridization groups at a cut-off level of 70% DNA binding.

Diversity of 746 heterotrophic bacteria isolated from microbial mats from ten Antarctic lakes.

Microbial mats, growing in Antarctic lakes constitute unique and very diverse habitats. In these mats microorganisms are confronted with extreme life conditions. We isolated 746 bacterial strains from mats collected from ten lakes in the Dry Valleys (lakes Hoare and Fryxell), the Vestfold Hills (lakes Ace, Druzhby, Grace, Highway, Pendant, Organic and Watts) and the Larsemann Hills (lake Reid), using heterotrophic growth conditions.

Microbiological aspects of biowaste during composting in a monitored compost bin.

Aims: To determine the microbial succession of the dominating taxa and functional groups of microorganisms and the total microbial activity during the composting of biowaste in a monitored process.

Methods And Results: Biowaste (vegetable, fruit and garden waste) was composted in a monitored composting bin system. During the process, taxonomic and functional subpopulations of microorganisms were enumerated, and dominating colonies were isolated and identified.

Phyllobacterium myrsinacearum (subjective synonym Phyllobacterium rubiacearum) emend.

The taxonomic relationships between Phyllobacterium myrsinacearum LMG 2t2T, Phyllobacterium rubiacearum LMG 1t1T and two Phyllobacterium strains representing a collection of isolates from sugar-beet roots were investigated by means of fatty acid analysis and DNA-DNA hybridization. The strains showed very similar fatty acid compositions and more than 96% DNA reassociation to each other. On the basis of these results and available data from the literature, it is proposed that P.

Fulvimonas soli gen. nov., sp. nov., a gamma-proteobacterium isolated from soil after enrichment on acetylated starch plastic.

Six deep-yellow-pigmented strains were isolated from soil after enrichment on plasticized acetylated starch granules as a source of carbon. They showed very similar and unique fatty acid profiles, consisting almost exclusively of branched fatty acids. The strains consisted of small, motile rods, were oxidase- and catalase-positive, did not ferment sugars and were able to depolymerize starch and suspended acetylated starch in overlayer plates.

Bacterial Blight and Dieback of Eucalyptus Species, Hybrids, and Clones in South Africa.

During 1998, a new disease appeared on trees representing a Eucalyptus grandis × E. nitens (GN) hybrid in a nursery in KwaZulu/Natal. The disease has subsequently spread to other Eucalyptus species, hybrids, and clones in nurseries and plantations throughout South Africa.

Natural cellulose fibers: heterogeneous acetylation kinetics and biodegradation behavior.

Steam-exploded fibers from flax (Linum usitatissimum) are heterogeneously acetylated using acetic anhydride and sulfuric acid as catalyst, with the aim to modify the surface properties without changing fiber structure and morphology. The acetylation reaction follows first-order kinetics up to a reaction time that depends on catalyst concentration (15 h when using 0.4 vol % of H(2)SO(4) or 50 h with 0.

Identity and potential functions of heterotrophic bacterial isolates from a continuous-upflow fixed-bed reactor for denitrification of drinking water with bacterial polyester as source of carbon and electron donor.

A collection of 186 heterotrophic bacteria, isolated directly from a continuous-upflow fixed-bed reactor for the denitrification of drinking water, in which poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) granules acted as biofilm carrier, carbon source and electron donor, was studied with regard to taxonomic affiliation and degradation and denitrification characteristics. Two granule samples were taken from a fully operating reactor for enumeration and isolation of heterotrophic bacteria. One sample was drawn from the lower part of the reactor, near the oxic zone, and the other sample from the upper, anoxic part of the fixed bed.