Isolation and characterization of a Halomonas species for non-axenic growth-associated production of bio-polyesters from sustainable feedstocks.

Biodegradable plastics are urgently needed to replace petroleum-derived polymeric materials and prevent their accumulation in the environment. To this end, we isolated and characterized a halophilic and alkaliphilic bacterium from the Great Salt Lake in Utah. The isolate was identified as a Halomonas species and designated "CUBES01." Full-genome sequencing and genomic reconstruction revealed the unique genetic traits and metabolic capabilities of the strain, including the common polyhydroxyalkanoate (PHA) biosynthesis pathway. Fluorescence staining identified intracellular polyester granules that accumulated predominantly during the strain's exponential growth, a feature rarely found among natural PHA producers. CUBES01 was found to metabolize a range of renewable carbon feedstocks, including glucosamine and acetyl-glucosamine, as well as sucrose, glucose, fructose, and further glycerol, propionate, and acetate. Depending on the substrate, the strain accumulated up to ~60% of its biomass (dry wt/wt) in poly(3-hydroxybutyrate), while reaching a doubling time of 1.7 h at 30°C and an optimum osmolarity of 1 M sodium chloride and a pH of 8.8. The physiological preferences of the strain may not only enable long-term aseptic cultivation but also facilitate the release of intracellular products through osmolysis. The development of a minimal medium also allowed the estimation of maximum polyhydroxybutyrate production rates, which were projected to exceed 5 g/h. Finally, also, the genetic tractability of the strain was assessed in conjugation experiments: two orthogonal plasmid vectors were stable in the heterologous host, thereby opening the possibility of genetic engineering through the introduction of foreign genes. IMPORTANCE: The urgent need for renewable replacements for synthetic materials may be addressed through microbial biotechnology. To simplify the large-scale implementation of such bio-processes, robust cell factories that can utilize sustainable and widely available feedstocks are pivotal. To this end, non-axenic growth-associated production could reduce operational costs and enhance biomass productivity, thereby improving commercial competitiveness. Another major cost factor is downstream processing, especially in the case of intracellular products, such as bio-polyesters. Simplified cell-lysis strategies could also further improve economic viability.

In Vivo Polymerization ("Hard-Wiring") of Bioanodes Enables Rapid Start-Up and Order-of-Magnitude Higher Power Density in a Microbial Battery.

For microbial electrochemical technologies to be successful in the decentralized treatment of wastewater, steady-state power density must be improved and cost must be decreased. Here, we demonstrate in vivo polymerization ("hard-wiring") of a microbial community to a growing layer of conductive polypyrrole on a sponge bioanode of a microbial battery, showing rapid biocatalytic current development (∼10 times higher than a sponge control after 4 h). Moreover, bioanodes with the polymerized inoculant maintain higher steady-state power density (∼2 times greater than the control after 28 days). We then evaluate the same hard-wired bioanodes in both a two-chamber microbial fuel cell and microbial battery with a solid-state NaFeIIFeIII(CN)6 (Prussian Blue) cathode, showing approximately an order-of-magnitude greater volumetric power density with the microbial battery. The result is a rapid start-up, low-cost (no membrane or platinum catalyst), and high volumetric power density system (independent of atmospheric oxygen) for harvesting energy and carbon from dilute organics in wastewater.

Prosthecobacter algae sp. nov., isolated from activated sludge using algal metabolites.

A Gram-stain-negative, fusiform-shaped, facultatively anaerobic bacterial strain, designated EBTL04(T), was isolated from activated sludge using algal metabolites and taxonomically characterized through polyphasic investigation. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain EBTL04(T) belongs to the family Verrucomicrobiaceae, class Verrucomicrobiae, and is closely related to Prosthecobacter dejongeii DSM 12251(T) (98.6 % sequence similarity), Prosthecobacter fusiformis ATCC 25309(T) (97.9 %), Prosthecobacter debontii DSM 14044(T) (97.5%), Prosthecobacter vanneervenii DSM 12252(T) (94.7%) and Prosthecobacter fluviatilis KCTC 22182(T) (93.7%). The G+C content of the genomic DNA of strain EBTL04(T) was 62.7 mol%. The menaquinone MK-6 was detected as the predominant quinone. Strain EBTL04(T) contained phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine as major polar lipids. A fatty acid profile with C(16 : 1)ω5c, iso-C(14 : 0), C(16 : 0), anteiso-C(15 : 0) and C(14 : 0) as the major components supported the classification of strain EBTL04(T) in the genus Prosthecobacter. Based on several phenotypic, genotypic and chemotaxonomic features, strain EBTL04(T) was clearly differentiated from its phylogenetic neighbours. Therefore, strain EBTL04(T) should be considered to represent a novel species of the genus Prosthecobacter, for which the name Prosthecobacter algae sp. nov. is proposed. The type strain is EBTL04(T) ( = KCTC 23681(T) = JCM 18053(T)).

Production of nitrous oxide from anaerobic digester centrate and its use as a co-oxidant of biogas to enhance energy recovery.

Coupled Aerobic-anoxic Nitrous Decomposition Operation (CANDO) is a new process for wastewater treatment that removes nitrogen from wastewater and recovers energy from the nitrogen in three steps: (1) NH4(+) oxidation to NO2(-); (2) NO2(-) reduction to N2O gas; and (3) N2O conversion to N2 with energy production. In this work, we optimize Steps 1 and 2 for anaerobic digester centrate, and we evaluate Step 3 for a full-scale biogas-fed internal combustion engine. Using a continuous stirred reactor coupled to a bench-scale sequencing batch reactor, we observed sustained partial oxidation of NH4(+) to NO2(-) and sustained (3 months) partial reduction of NO2(-) to N2O (75-80% conversion, mass basis), with >95% nitrogen removal (Step 2). Alternating pulses of acetate and NO2(-) selected for Comamonas (38%), Ciceribacter (16%), and Clostridium (11%). Some species stored polyhydroxybutyrate (PHB) and coupled oxidation of PHB to reduction of NO2(-) to N2O. Some species also stored phosphorus as polyphosphate granules. Injections of N2O into a biogas-fed engine at flow rates simulating a full-scale system increased power output by 5.7-7.3%. The results underscore the need for more detailed assessment of bioreactor community ecology and justify pilot- and full-scale testing.

Pseudomonas stutzeri KC carries the pdt genes for carbon tetrachloride degradation on an integrative and conjugative element.

Pseudomonas stutzeri KC can rapidly degrade carbon tetrachloride (CCl4) to CO2 by a fortuitous reaction with pyridine-2,6-bis(thiocarboxylic acid), a metal chelator encoded by pdt genes. These genes were first identified after a spontaneous mutant, strain CTN1, lost the ability to degrade CCl4. Here we report the complete genome of strain KC and show that these pdt genes are located on an integrative and conjugative element (ICE), designated ICEPsstKC. Comparative genome analyses revealed homologues of pdt genes in genomes of members of other gammaproteobacterial orders. Discrepancies between the tree topologies of the deduced pdt gene products and the host phylogeny based on 16S rRNA provided evidence for horizontal gene transfer (HGT) in several sequenced strains of these orders. In addition to ICEPsstKC, HGT may be have been facilitated by other mobile genetic elements, as indicated by the location of the pdt gene cluster adjacent to fragments of other ICEs and prophages in several genome assemblies. We could here show that the majority of cells from the culture collection DSMZ had lost the ICE. The presence of the pdt gene cluster on mobile genetic elements has important implications for the bioremediation of CCl4 for bioremediation of CCl4 and needs consideration when selecting suitable strains.

Luteolibacter yonseiensis sp. nov., isolated from activated sludge using algal metabolites.

A Gram-negative, rod-shaped, aerobic bacterial strain, designated EBTL01(T), was isolated from activated sludge by using metabolites of microalgae Ankistrodesmus gracilis SAG278-2. Phylogenetic analyses based on 16S rRNA gene sequence showed that strain EBTL01(T) belongs to the family Verrucomicrobiaceae, class Verrucomicrobiae, and is related most closely to Luteolibacter pohnpeiensis A4T-83(T) (95.5 % sequence similarity) and Luteolibacter algae A5J-41-2(T) (95.2 %). The G+C content of the genomic DNA of strain EBTL01(T) was 56.3 mol% and the menaquinone MK-9 was detected as the predominant quinone. Major fatty acid components were iso-C14 : 0, C16 : 1ω7c and C16 : 0. The amino acids of the cell-wall peptidoglycan contained muramic acid and meso-diaminopimelic acid. These profile results supported the affiliation of strain EBTL01(T) to the genus Luteolibacter. On the other hand, based on chemotaxonomic properties and phenotypic characteristics, strain EBTL01(T) could be clearly differentiated from its phylogenetic neighbours. Therefore, strain EBTL01(T) represents a novel species of the genus Luteolibacter, for which the name Luteolibacter yonseiensis sp. nov. is proposed. The type strain is EBTL01(T) ( = KCTC 23678(T) = JCM 18052(T)).

Brevibacterium daeguense sp. nov., a nitrate-reducing bacterium isolated from a 4-chlorophenol enrichment culture.

A Gram-reaction-positive, non-spore-forming, aerobic actinobacterial strain (2C6-41(T)) was isolated from the activated sludge from an industrial wastewater treatment plant in Daegu, South Korea. Its taxonomic position was investigated by using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity, closest phylogenetic relatives to strain 2C6-41(T) were Brevibacterium pityocampae DSM 21720(T) (97.2 %), Brevibacterium salitolerans KCTC 19616(T) (96.7 %), Brevibacterium album KCTC 19173(T) (96.2 %) and Brevibacterium samyangense KCCM 42316(T) (96.2 %). The DNA G+C content of strain 2C6-41(T) was 66.4 mol%. Chemotaxonomic data, which included MK-8(H(2)) as the major menaquinone; meso-diaminopimelic acid, glutamic acid and alanine as cell-wall amino acids; ribose, mannose and glucose as major cell-wall sugars; and anteiso-C(15 : 0), anteiso-C(17 : 0), C(16 : 0) and iso-C(15 : 0) as major fatty acids, supported the affiliation of strain 2C6-41(T) to the genus Brevibacterium. The aromatic ring cleavage enzyme catechol 1,2-dioxygenase was not detected in strain 2C6-41(T), but catechol 2,3-dioxygenase was detected. The results of physiological and biochemical tests, and the low level of DNA-DNA relatedness to the closest phylogenetic relative enabled strain 2C6-41(T) to be differentiated genotypically and phenotypically from recognized species of the genus Brevibacterium. The isolate is therefore considered to represent a novel species in the genus Brevibacterium, for which the name Brevibacterium daeguense sp. nov. is proposed. The type strain is 2C6-41(T) (=KCTC 19800(T) = JCM 17458(T)).

Nocardioides daeguensis sp. nov., a nitrate-reducing bacterium isolated from activated sludge of an industrial wastewater treatment plant.

A Gram-reaction-positive, rod-shaped, non-spore-forming bacterium (strain 2C1-5(T)) was isolated from activated sludge of an industrial wastewater treatment plant in Daegu, South Korea. Its taxonomic position was investigated by using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity, the closest phylogenetic relatives were the type strains of Nocardioides nitrophenolicus (98.6 % similarity), N. kongjuensis (98.5 %), N. caeni (98.4 %), N. simplex (98.3 %), N. aromaticivorans (98.1 %) and N. ginsengisoli (97.5 %); the phylogenetic distance from other species with validly published names within the genus Nocardioides was greater than 3 %. Strain 2C1-5(T) was characterized chemotaxonomically as having ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, MK-8(H4) as the predominant menaquinone and iso-C16 : 0, C16 : 0 and C17 : 1ω6c as the major fatty acids. The G+C content of the genomic DNA was 74.9 mol%. These chemotaxonomic properties and phenotypic characteristics supported the affiliation of strain 2C1-5(T) to the genus Nocardioides. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 2C1-5(T) from existing species with validly published names. Therefore, strain 2C1-5(T) represents a novel species of the genus Nocardioides, for which the name Nocardioides daeguensis sp. nov. is proposed, with the type strain 2C1-5(T) ( = JCM 17460(T) = KCTC 19799(T)).

Rhodanobacter caeni sp. nov., isolated from sludge from a sewage disposal plant.

Two Gram-reaction-negative, motile bacteria, designated strains MJ01(T) and MJ14, were isolated from sludge collected from the Daejeon sewage disposal plant in South Korea. The taxonomic positions of both strains were determined using a polyphasic approach. In phylogenetic analyses based on 16S rRNA gene sequences, strains MJ01(T) and MJ14 appeared indistinguishable and to be most closely related to members of the genus Rhodanobacter in the family Xanthomonadaceae of the Gammaproteobacteria (96.4-98.8% sequence similarity). Strain MJ01(T) exhibited a relatively high level of DNA-DNA relatedness with strain MJ14 (89.3 %) but relatively low DNA-DNA relatedness values with established species in the genus Rhodanobacter (<60 %). The genomic DNA G+C contents of strains MJ01(T) and MJ14 were 65.3 and 64.8 mol%, respectively. The major respiratory quinone of both novel strains was the ubiquinone Q-8. The major fatty acids of both strains were iso-C(15 : 0), iso-C(16 : 0), iso-C(17:0) and iso-C(17 : 1)ω9c, and the polar lipid profiles of the two strains contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and minor amounts of unidentified aminophospholipids and phospholipids. Based on the phenotypic, genotypic and phylogenetic evidence, strains MJ01(T) and MJ14 represent a single novel species in the genus Rhodanobacter, for which the name Rhodanobacter caeni sp. nov. is proposed. The type strain is MJ01(T) ( = KCTC 22449(T) = JCM 16242(T)), with MJ14 ( = KCTC 22460 = JCM 16243) as a reference strain.

Nocardioides daejeonensis sp. nov., a denitrifying bacterium isolated from sludge in a sewage-disposal plant.

Strain MJ31(T), a gram-reaction-positive, aerobic, rod-shaped, non-motile bacterium, was isolated from a sludge sample collected at the Daejeon sewage-disposal plant, in South Korea, and characterized in order to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MJ31(T) belonged to the genus Nocardioides, appearing most closely related to Nocardioides dubius KSL-104(T) (98.6 % sequence similarity), Nocardioides jensenii DSM 20641(T) (97.6 %), Nocardioides daedukensis MDN22(T) (97.2 %) and Nocardioides mesophilus MSL-22(T) (97.0 %). The chemotaxonomic properties of strain MJ31(T) were consistent with those of the genus Nocardioides: MK-8(H(4)) was the predominant menaquinone, iso-C(16 : 0), iso-C(17 : 0) and C(18 : 1)ω9c were the predominant cellular fatty acids, and the cell-wall peptidoglycan was based on LL-2,6-diaminopimelic acid. The genomic DNA G+C content of strain MJ31(T) was 71.2 mol%. Some differential phenotypic properties and low DNA-DNA relatedness values (<28 %) with the type strains of closely related species indicated that strain MJ31(T) represents a novel species, for which the name Nocardioides daejeonensis sp. nov. is proposed. The type strain is MJ31(T) ( = KCTC 19772(T) = JCM 16922(T)).

Georgenia daeguensis sp. nov., isolated from 4-chlorophenol enrichment culture.

During screening for 4-chlorophenol-degrading micro-organisms in activated sludge from industrial wastewater treatment, a Gram-positive, rod-shaped, aerobic bacterial strain, designated 2C6-43(T), was isolated and characterized taxonomically by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain 2C6-43(T) belongs to the family Bogoriellaceae, class Actinobacteria, and is related most closely to Georgenia soli CC-NMPT-T3(T) (98.8% sequence similarity), Georgenia muralis 1A-C(T) (97.6%), Georgenia thermotolerans TT02-04(T) (96.8%), Georgenia ruanii YIM 004(T) (96.6%) and Georgenia halophila YIM 93316(T) (96.0%). The G+C content of the genomic DNA of strain 2C6-43(T) was 66.2 mol%. Sugars from whole-cell hydrolysates found in strain 2C6-43(T) were rhamnose, ribose and galactose. The menaquinone MK-8(H(4)) was detected as the predominant quinone. Polar lipid analysis of 2C6-43(T) revealed diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol and phosphatidylglycerol. An aromatic compound ring cleavage enzyme of catechol 1,2-dioxygenase was detected but catechol 2,3-dioxygenase was not detected in 2C6-43(T). A fatty acid profile with anteiso-C(15:0), iso-C(15:0) and C(16:0) as the major components supported the affiliation of strain 2C6-43(T) to the genus Georgenia. However, the DNA-DNA relatedness between strain 2C6-43(T) and the type strains of five species of the genus Georgenia ranged from 17 to 40%, clearly showing that the isolate constitutes a new genospecies. Strain 2C6-43(T) could be clearly differentiated from its phylogenetic neighbours on the basis of some phenotypic, genotypic and chemotaxonomic features. Therefore, strain 2C6-43(T) is considered to represent a novel species of the genus Georgenia, for which the name Georgenia daeguensis sp. nov. is proposed; the type strain is 2C6-43(T) (=KCTC 19801(T)=JCM 17459(T)).

Characterization of novel diesel-degrading strains Acinetobacter haemolyticus MJ01 and Acinetobacter johnsonii MJ4 isolated from oil-contaminated soil.

The diesel-degrading strains, designated as MJ01 and MJ4, were isolated from oil-contaminated soil in Daejeon (South Korea) and were taxonomically characterized using a polyphasic approach and their diesel oil degradation abilities were analyzed. The isolates MJ01 and MJ4 were identified as Acinetobacter haemolyticus and Acinetobacter johnsonii, respectively, based on their 16S rDNA gene sequences, DNA-DNA relatedness, fatty acid profiles and various physiological characteristics. Strains MJ01 and MJ4 were able to use diesel oil as the sole carbon and energy source. Both strains could degrade over 90% of diesel oil with an initial concentration of 20,000 mg/l after incubation for 7 days, the most significant degradation occurred during the first 3 days. To our knowledge, this is the first report on diesel oil-degrading microorganisms among bacterial strains belonging to A. haemolyticus and A. johnsonii.

Shinella daejeonensis sp. nov., a nitrate-reducing bacterium isolated from sludge of a leachate treatment plant.

A Gram-negative-staining, motile, rod-shaped, aerobic bacterial strain, designated MJ02(T), was isolated from sludge of a leachate treatment plant in Daejeon (South Korea) and was characterized to determine its taxonomic position by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain MJ02(T) belonged to the family Rhizobiaceae, class Alphaproteobacteria, and was most closely related to Shinella yambaruensis MS4(T) (97.6 % sequence similarity) and Shinella fusca DC-196(T) (97.5 %). The G+C content of the genomic DNA of strain MJ02(T) was 64.3 mol%. The detection of a quinone system with ubiquinone Q-10 as the predominant respiratory lipoquinone and a fatty acid profile with C18:1ω7c (45.8 %) and C16:0 (21.8 %) as the major components supported the affiliation of strain MJ02(T) to the genus Shinella. However, strain MJ02(T) exhibited relatively low levels of DNA-DNA relatedness with respect to S. fusca DSM 21319(T) (17±7 %) and S. yambaruensis KACC 14483(T) (12±6 %), showing clearly that the isolate constituted a new genospecies. Strain MJ02(T) could be clearly differentiated from its phylogenetic neighbours on the basis of several phenotypic, genotypic and chemotaxonomic features. Therefore, strain MJ02(T) is considered to represent a novel species of the genus Shinella, for which the name Shinella daejeonensis sp. nov. is proposed. The type strain is MJ02(T) ( = KCTC 22450(T) = JCM 16236(T)).

Ochrobactrum daejeonense sp. nov., a nitrate-reducing bacterium isolated from sludge of a leachate treatment plant.

A Gram-reaction-negative, non-spore-forming, rod-shaped, aerobic bacterial strain, designated MJ11(T), was isolated from sludge of a leachate treatment plant in Daejeon, South Korea, and was characterized taxonomically by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain MJ11(T) belonged to the family Brucellaceae, class Alphaproteobacteria, and was most closely related to Ochrobactrum ciceri Ca-34(T) (97.9 % sequence similarity) and Ochrobactrum pituitosum CCUG 50899(T) (96.4 %). Comparative sequence analyses of the additional phylogenetic marker genes dnaK, groEL and gyrB confirmed the affiliation of strain MJ11(T) to the genus Ochrobactrum. The G+C content of the genomic DNA of strain MJ11(T) was 59.3 mol%. The detection of a quinone system with ubiquinone Q-10 as the predominant respiratory lipoquinone, a fatty acid profile with C(18 : 1)ω7c (62.6 %) and C(19 : 0) cyclo ω8c (14.2 %) as the major components, a polar lipid profile with phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol and unknown aminolipids AL1 and AL2 as major polar lipids and spermidine and putrescine as the predominant polyamines also supported the affiliation of strain MJ11(T) to the genus Ochrobactrum. The DNA-DNA relatedness between strain MJ11(T) and Ochrobactrum ciceri DSM 22292(T) was 29 ± 7 %, clearly showing that the isolate constitutes a new genospecies. Strain MJ11(T) could be clearly differentiated from its closest neighbours on the basis of its phenotypic, genotypic and chemotaxonomic features. Therefore, strain MJ11(T) represents a novel species of the genus Ochrobactrum, for which the name Ochrobactrum daejeonense sp. nov. is proposed. The type strain is MJ11(T) ( = KCTC 22458(T) = JCM 16234(T)).

Agromyces soli sp. nov., isolated from farm soil.

A Gram-positive, aerobic to microaerophilic, non-motile bacterial strain, designated MJ21(T), was isolated from farm soil and was characterized to determine its taxonomic position by using a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, strain MJ21(T) was placed within the genus Agromyces, and exhibited relatively high levels of similarity to Agromyces ulmi XIL01(T) (97.8 %), Agromyces aurantiacus YIM 21741(T) (97.1 %), Agromyces mediolanus JCM 3346(T) (96.7 %), A. mediolanus JCM 1376 (99.1 %), A. mediolanus JCM 9632 (99.1 %), A. mediolanus JCM 9633 (98.9 %) and A. mediolanus JCM 9631 (96.5 %). Chemotaxonomic data also supported the classification of strain MJ21(T) within the genus Agromyces. The new isolate contained MK-12 as the predominant menaquinone and rhamnose, galactose and xylose as cell-wall sugars. The major cellular fatty acids (>10 % of the total) were anteiso-C(15 : 0), anteiso-C(17 : 0) and iso-C(16 : 0). Cell-wall amino acids were 2,4-diaminobutyric acid, glutamic acid, glycine and alanine. Diphosphatidylglycerol, phosphatidylglycerol, two unknown glycolipids and one unidentified phospholipid were detected as polar lipids. The DNA G+C content of strain MJ21(T) was 73.4 mol%. However, levels of DNA-DNA relatedness between strain MJ21(T) and the seven phylogenetically closest Agromyces strains ranged from 14 to 56 %, showing clearly that the new isolate represents a novel genomic species. Strain MJ21(T) could be differentiated clearly from its phylogenetic neighbours on the basis of phenotypic, genotypic and chemotaxonomic features. Therefore, strain MJ21(T) is considered to represent a novel species of the genus Agromyces, for which the name Agromyces soli sp. nov. is proposed. The type strain is MJ21(T) ( = KCTC 19549(T)  = JCM 16247(T)).

Stenotrophomonas daejeonensis sp. nov., isolated from sewage.

A Gram-stain-negative, motile, aerobic bacterial strain, designated MJ03(T), was isolated from sewage and was characterized taxonomically by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain MJ03(T) belongs to the family Xanthomonadaceae, class Gammaproteobacteria, and was related most closely to Stenotrophomonas acidaminiphila AMX 19(T) (97.9  % sequence similarity), Stenotrophomonas humi R-32729(T) (97.1  %), Stenotrophomonas nitritireducens L2(T) (96.9  %), Stenotrophomonas maltophila ATCC 13637(T) (96.8  %) and Stenotrophomonas terrae R-32768(T) (96.7  %). The G+C content of the genomic DNA of strain MJ03(T) was 64.7 mol%. The detection of a quinone system with ubiquinone Q-8 as the predominant component and a fatty acid profile with iso-C15:0, iso-C11:0, iso-C14:0, iso-C17:1ω9c, iso-C11:0 3-OH and iso-C13:0 3-OH as major components supported the affiliation of strain MJ03(T) to the genus Stenotrophomonas. However, levels of DNA-DNA relatedness between strain MJ03(T) and the type strains of five closely related species of the genus Stenotrophomonas ranged from 11 to 34  %, showing clearly that the isolate represents a novel genospecies. Strain MJ03(T) could be differentiated clearly from its phylogenetic neighbours on the basis of several phenotypic, genotypic and chemotaxonomic features. Therefore, strain MJ03(T) is considered to represent a novel species of the genus Stenotrophomonas, for which the name Stenotrophomonas daejeonensis sp. nov. is proposed. The type strain is MJ03(T) (=KCTC 22451(T) =JCM 16244(T)).

Pusillimonas soli sp. nov., isolated from farm soil.

A Gram-negative, motile, non-spore-forming bacterial strain, designated MJ07(T), was isolated from a farm soil and was characterized to determine its taxonomic position by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain MJ07(T) belongs to the family Alcaligenaceae, class Betaproteobacteria, and is related most closely to Pusillimonas ginsengisoli KCTC 22046(T) (98.6 % sequence similarity) and Pusillimonas noertemannii BN9(T) (96.9 %). The levels of 16S rRNA gene sequence similarity between strain MJ07(T) and members of all other recognized species of the family Alcaligenaceae were below 95.2 %. The G+C content of the genomic DNA of strain MJ07(T) was 59.4 mol%. The detection of a quinone system with ubiquinone Q-8 as the major respiratory lipoquinone, putrescine as the predominant polyamine, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and two unknown aminolipids as major polar lipids and a fatty acid profile with C16:0 (32.0 %), C17:0cyclo (24.7 %) and C19:0cyclo ω8c (11.5 %) as the major components supported the affiliation of strain MJ07(T) to the genus Pusillimonas. Strain MJ07(T) exhibited relatively low levels of DNA-DNA relatedness with respect to P. ginsengisoli KCTC 22046(T) (50 ± 8 %) and P. noertemannii KACC 13183(T) (18 ± 7 %). On the basis of its phenotypic and genotypic properties together with its phylogenetic distinctiveness, strain MJ07(T) (=KCTC 22455(T) =JCM 16386(T)) should be classified in the genus Pusillimonas as the type strain of a novel species, for which the name Pusillimonas soli sp. nov. is proposed.

Dyadobacter soli sp. nov., a starch-degrading bacterium isolated from farm soil.

A Gram-negative, non-motile, aerobic bacterial strain, designated MJ20(T), was isolated from farm soil near Daejeon (South Korea) and was characterized taxonomically by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain MJ20(T) belongs to the family Cytophagaceae, class Sphingobacteria, and was related most closely to Dyadobacter fermentans DSM 18053(T) (98.9 % sequence similarity), Dyadobacter beijingensis JCM 14200(T) (98.0 %) and Dyadobacter ginsengisoli KCTC 12589(T) (96.4 %). The G+C content of the genomic DNA of strain MJ20(T) was 48.5 mol%. The detection of MK-7 as the predominant menaquinone and a fatty acid profile with summed feature 4 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH), iso-C(15 : 0), C(16 : 0) and C(16 : 1)ω5c as major components supported the affiliation of strain MJ20(T) to the genus Dyadobacter. The new isolate exhibited relatively low levels of DNA-DNA relatedness with respect to D. fermentans DSM 18053(T) (mean±SD of three determinations, 47±7 %) and D. beijingensis JCM 14200(T) (38±8 %). On the basis of its phenotypic and genotypic properties together with phylogenetic distinctiveness, strain MJ20(T) (=KCTC 22481(T) =JCM 16232(T)) should be classified in the genus Dyadobacter as the type strain of a novel species, for which the name Dyadobacter soli sp. nov. is proposed.

Nitrogen removal as nitrous oxide for energy recovery: Increased process stability and high nitrous yields at short hydraulic residence times.

The Coupled Aerobic-anoxic Nitrous Decomposition Operation (CANDO) is a two-stage process for nitrogen removal and resource recovery: in the first, ammonia is oxidized to nitrite in an aerobic bioreactor; in the second, oxidation of polyhydroxyalkanoate (PHA) drives reduction of nitrite to nitrous oxide (N2O) which is stripped for use as a biogas oxidant. Because ammonia oxidation is well-studied, tests of CANDO to date have focused on N2O production in anaerobic/anoxic sequencing batch reactors. In these reactors, nitrogen is provided as nitrite; PHA is produced from acetate or other dissolved COD, and PHA oxidation is coupled to N2O production from nitrite. In a pilot-scale study, N2O recovery was affected by COD/N ratio, total cycle time, and relative time periods for PHA synthesis and N2O production. In follow-up bench-scale studies, different reactor cycle times were used to investigate these operational parameters. Increasing COD/N ratio improved nitrite removal and increased biosolids concentration. Shortening the anaerobic phase prevented fermentation of PHA and improved its utilization. Efficient PHA synthesis and utilization in the anaerobic phase correlated with high N2O production in the anoxic phase. Shortening the anoxic phase prevented reduction of N2O to N2. By shortening both phases, total cycle time was reduced from 24 to 12 h. This optimized operation enabled increased biomass concentrations, increased N2O yields (from 71 to 87%), increased N loading rates (from 0.1 to 0.25 kg N/m3-d), and shorter hydraulic residence times (from 10 to 2 days). Long-term changes in operational performance for the different bioreactor systems tested were generally similar despite significant differences in microbial community structure. Long-term operation at short anaerobic phases selected for a glycogen-accumulating community dominated by a Defluviicoccus-related strain.

Disassembly and reassembly of polyhydroxyalkanoates: recycling through abiotic depolymerization and biotic repolymerization.

An abiotic-biotic strategy for recycling of polyhydroxyalkanoates (PHAs) is evaluated. Base-catalyzed PHA depolymerization yields hydroxyacids, such as 3-hydroxybutyrate (3HB), and alkenoates, such as crotonate; catalytic thermal depolymerization yields alkenoates. Cyclic pulse addition of 3HB to triplicate bioreactors selected for an enrichment of Comamonas, Brachymonas and Acinetobacter. After each pulse, poly(3-hydroxybutyrate) (P3HB) transiently appeared: accumulation of P3HB correlated with hydrolysis of polyphosphate; consumption of P3HB correlated with polyphosphate synthesis. Cells removed from the cyclic regime and incubated with 3HB under nitrogen-limited conditions produced P3HB (molecular weight>1,000,000Da) at 50% of the cell dry weight (<8h). P3HB also resulted from incubation with acetate, crotonate, or a mixture of hydrolytic depolymerization products. Poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) resulted from incubation with valerate or 2-pentenoate. A recycling strategy where abiotic depolymerization of waste PHAs yields feedstock for customized PHA re-synthesis appears feasible, without the need for energy-intensive feedstock purification.