Isolation and characterization of isopimaric acid-degrading bacteria from a sequencing batch reactor.

We isolated two aerobic, gram-negative bacteria which grew on the diterpene resin acid isopimaric acid (IpA) as the sole carbon source and electron donor. The source of the isolates was a sequencing batch reactor treating a high-strength process stream from a paper mill. The isolates, IpA-1 and IpA-2, also grew on pimaric and dehydroabietic acids, and IpA-1 grew on abietic acid. Both strains used fatty acids, but neither strain used camphor, sitosterol, or betulin. Strain IpA-1 grew anaerobically with nitrate as an electron acceptor. Strains IpA-1 and IpA-2 had growth yields of 0.19 and 0.23 g of protein per g of IpA, respectively. During growth, both strains transformed IpA carbon to approximately equal amounts of biomass, carbon dioxide, and dissolved organic carbon. In both strains, growth on IpA induced an enzymatic system which caused cell suspensions to transform all four of the above resin acids. Cell suspensions of IpA-1 and IpA-2 removed IpA at rates of 0.56 and 0.13 mumol mg of protein-1 h-1, respectively. Cultures and cell suspensions of both strains failed to completely consume pimaric acid and yielded small amounts of an apparent metabolite from this acid. Cultures and cell suspensions of both strains yielded large amounts of three apparent metabolites from dehydroabietic acid. Analysis of 16S rDNA sequences indicated that the isolates are distinct members of the genus Pseudomonas sensu stricto.     

Isolation and characterization of a 2,4-dichlorophenoxyacetic acid-degrading soil bacterium

Summary A 2,4-dichlorophenoxyacetic acid (2,4-D)-degrading bacterial strain, Xanthobacter sp. CP, was isolated after enrichment in aerated soil columns. A limited number of chlorinated phenols and chlorinated phenoxyalkanoic acids with an even number of carbon atoms in the side chain served as substrates for growth, although whole cells exhibited oxygen uptake with a wide range of those compounds. The maximal growth rate with 2,4-D was 0.13·h^-1 at a growth yield of 0.1 g biomass/g 2,4-D. Chloride ions were released quantitatively from 2,4-D and related chlorinated aromatic compounds which served as growth substrates. No by-products of 2,4-D metabolism were detected in oxygen-sufficient cultures of Xanthobacter sp. CP and catechols were cleaved exclusively by catechol 1,2-dioxygenase.     

Isolation and characterization of haloacetic acid-degrading Afipia spp. from drinking water

Haloacetic acids are a class of disinfection byproducts formed during the chlorination and chloramination of drinking water that have been linked to several human health risks. In this study, we isolated numerous strains of haloacetic acid-degrading Afipia spp. from tap water, the wall of a water distribution pipe, and a granular activated carbon filter treating prechlorinated water. These Afipia spp. harbored two phylogenetically distinct groups of α-halocarboxylic acid dehalogenase genes that clustered with genes previously detected only by cultivation-independent methods or were novel and did not conclusively cluster with the previously defined phylogenetic subdivisions of these genes. Four of these Afipia spp. simultaneously harbored both the known classes of α-halocarboxylic acid dehalogenase genes ( deh I and deh II), which is potentially of importance because these bacteria were also capable of biodegrading the greatest number of different haloacetic acids. Our results suggest that Afipia spp. have a beneficial role in suppressing the concentrations of haloacetic acids in tap water, which contrasts the historical (albeit erroneous) association of Afipia sp. (specifically Afipia felis ) as the causative agent of cat scratch disease.     

降解全氟辛酸真菌的分离与鉴定

目的 通过富集培养分离降解全氟辛酸（PFOA）的真菌,进行分类鉴定和降解特性分析。方法 采集全氟化合物污染的土壤,利用以PFOA为唯一碳源的无机盐培养基进行驯化和富集培养,分离降解PFOA的真菌;通过形态观察和基于ITS基因序列的系统发育分析对分离菌株进行鉴定;采用LC-MS检测其降解PFOA的能力。结果 分离获得2株降解PFOA的真菌AF1和AF2,初步鉴定分别为棘孢木霉（Trichoderma asperellum）和棘卷枝毛霉（Mucor circinelloides）;胞外酶活性分析均具有漆酶活性。真菌AF1和AF2在以PFOA为唯一碳源的无机盐培养基中培养72 h后,最大降解率分别为24.24%和28.12%。结论 自然环境中蕴藏着降解PFOA的真菌资源。     

Isolation and characterization of oil-desulphurizing bacteria

The objective of this study was to isolate local bacterial strains capable of removing sulphur from oil fractions without degrading the hydrocarbon. Oil biodesulphurization is an important step in combating pollution problems emanating from burning fossil fuels. Organisms which survive on oil are plentiful in local Kuwaiti soils; however, those that selectively only attack the carbon–sulphur bond are more difficult to find. Three strains were isolated based on their ability to use dibenzothiophene (DBT) as a sole source of sulphur for growth at 30 °C. Similar to other biodesulphurization organisms, the strains convert DBT to [2-hydroxybiphenyl (2-HBP) as detected by gas chromatography (GC). The specific desulphurization activity was in the range 5–13 mol 2-HBP/g-cell × h. Identification of the strains, based on 16 rRNA gene sequence similarity, showed the strains to be Rhodococcus erythropolis and Rhodococcus globerulus. The biodesulphurization activity was enhanced by promoting oxidore-ductase enzyme co-expression through the addition of a carbon source. The desulphurization was limited by the availability of DBT to the organism. Interfacial mass transfer through the aqueous-organic layer was confirmed to be a limiting factor.     

Isolation and characterization of dibenzofuran-degrading bacteria

Two bacterial strains capable of utilizing dibenzofuran (DF) as a sole carbon source were isolated from soil samples of reclaimed land. The strains designated HL1 and HL7 were identified as Klebsiella sp. and Sphingomonas sp., respectively, on the basis of biochemical characteristics and the sequences of the 16S ribosomal DNA. Sphingomonas sp. strain HL7 degraded non-, mono- and also dichlorinated DF and dibenzo-p-dioxin (DD). Klebsiella sp. strain HL1 was able to degrade non- and monochlorinated DFs and DDs, but not dichlorinated ones. The metabolites formed from DF by strains HL1 and HL7 were similar to those by dioxin-degrading bacteria Sphingomonas sp. strain RW1 except for salicylic acid and catechol. Strain HL7 had a gene homologous to that encoding the dioxin dioxygenase alpha-subunit (dxnA1) gene of Sphingomonas sp. strain RW1. However, Southern hybridization analysis showed that the size of an EcoRV-digested genomic fragment involving the dioxin dioxygenase gene of strain HL7 was smaller than that of strain RW1, and that strain HL1 did not have the homologous gene. Strains HL1 and HL7 provided useful information regarding the dioxygenase genes.     

Isolation and characterization of a 2-(2,4-dichlorophenoxy) propionic acid-degrading soil bacterium

Summary The 2-(2,4-dichlorphenoxy)propionic acid (2,4-DP)-degrading bacterial strain MH was isolated after numerous subcultivations of a mixed culture obtained by soil-column enrichment and finally identified as Flavobacterium sp. Growth of this strain was supported by 2,4-DP (maximum specific growth rate 0.2 h^–1) as well as by 2,4-dichlorophenoxyacetic acid (2,4-D), 4(2,4-dichlorophenoxy)butyric acid (2,4-DB), and 2-(4-chloro-2-methyphenoxy)propionic acid (MCPP) as sole sources of carbon and energy under aerobic conditions. 2,4-DP-Grown cells (10⁸) of strain MH degraded 2,4-dichlorophenoxyalkanoic acids, 2,4-dichlorophenol (2,4-DCP), and 4-chlorophenol at rates in the range of 30 nmol/h. Preliminary investigations indicate that cleavage of 2,4-DP results in 2,4-DCP, which is further mineralized via ortho-hydroxylation and ortho-cleavage of the resulting 3,5-dichlorocatechol. Offprint requests to: F. Streichsbier     

Isolation and characterization of two new methanesulfonic acid-degrading bacterial isolates from a Portuguese soil sample

Two novel bacterial strains that can utilize methanesulfonic acid as a source of carbon and energy were isolated from a soil sample collected in northern Portugal. Morphological, physiological, biochemical and molecular biological characterization of the two isolates indicate that strain P1 is a pink-pigmented facultative methylotroph belonging to the genus Methylobacterium, while strain P2 is a restricted methylotroph belonging to the genus Hyphomicrobium. Both strains are strictly aerobic, degrade methanesulfonate, and release small quantities of sulfite into the medium. Growth on methanesulfonate induces a specific polypeptide profile in each strain. This, together with the positive hybridization to a DNA probe that carries the msm genes of Methylosulfonomonas methylovora strain M2, strongly endorses the contention that a methanesulfonic acid monooxygenase related to that found in the previously known methanesulfonate-utilizing bacteria is present in strains P1 and P2. The isolation of bacteria containing conserved msm genes from diverse environments and geographical locations supports the hypothesis that a common enzyme may be globally responsible for the oxidation of methanesulfonate by natural methylotrophic communities.     

Isolation and characterization of marine oligotrophic bacteria

A significant part of the world ocean is characterized by low absolute nutrients and chlorophyll concentrations. In these oligotrophic environments, bacteria are very abundant and play a vital role in the remineralization of the dissolved organic matter. Bacteria adapted to oligotrophic waters differ from those adapted to richer environments by some genetic and metabolic characteristics. Culture techniques in bacteriology are based on rich media and do not allow the growth of most marine bacteria. New techniques have been developed for the culture of oligotrophic bacteria, which allow to isolate unknown bacteria. Pelagibacter ubique and Sphingopyxis alaskensis belong to these bacteria recently isolated from the marine environment and their study yielded better understanding of how marine bacteria adapt to oligotrophic conditions.     

二苯并噻吩分解菌的分离及特性研究

目的利用二苯并噻吩(DBT)分解菌的分离培养基从昆明捞鱼河的污泥中分离得到一株分解DBT的细菌HWXFJ2。方法通过形态观察、生理生化特征和16S rRNA基因序列分析,表明该菌属于革兰阳性菌、杆状、有荚膜,将其初步鉴定为黄色杆菌属的一株菌株;同时利用该菌株进行DBT分解能力的检测和研究。结果该菌株对DBT有较强的分解能力,在7 d和14 d对DBT分解的量分别是红球菌(Rhodococcus sp.HNCS21)的6.04倍和2.07倍。结论煤炭中的有机硫模式化合物为DBT,本研究可以为脱除煤炭中的有机硫提供理论依据,为进一步的应用提供菌种资源。     

Isolation and characterization of filterable marine bacteria

Anderson, J. I. W. (Northeast Shellfish Sanitation Research Center, Narragansett, R.I.), and W. P. Heffernan. Isolation and characterization of filterable marine bacteria. J. Bacteriol 90:1713-1718. 1965.-By a process of double filtration of seawater, first through a membrane filter with a pore diameter of 0.45 mu and then through a membrane filter with a pore diameter of 0.22 mu, it was possible to isolate on the surface of the latter membrane a group of marine organisms not usually encountered by conventional techniques of pour plates or one-stage filtration. Many of the isolates could not be identified, but the largest single group belonged to the genus Spirillum; other isolates were placed in the genera Leucothrix, Flavobacterium, Cytophaga, and Vibrio. A group of four organisms which was not identified was characterized by the formation of large, club-shaped cells, 20 to 30 mu long. Of the 25 strains studied in detail, 22 required seawater for growth and 8 retained their filterable property after cultivation. No filterable bacteria were isolated from terrestrial samples.     

Isolation and characterization of cesium-accumulating bacteria.

Cesium-accumulating bacteria, strains CS98 and CS402, were isolated from soil by a radioactive autoradiographic method using 137Cs. These strains displayed the rod-coccus growth cycle and contained mesodiaminopimelic acid, mycolic acids, and tuberculostearic acids. The major menaquinone of CS98 was MK-8(H2). On the basis of these characteristics, strain CS98 was identified as Rhodococcus erythropolis and strain CS402 was classified in the genus Rhodococcus. The maximum values of cesium removal efficiencies in the liquid culture containing 10 mumol of cesium per liter for strains CS98 and CS402 were 90 and 47%, respectively. The maximum cesium contents in strains CS98 and CS402 were 52.0 and 18.8 mumol/g (dry weight) of cells, respectively. Maximum values of cesium concentration factors for strains CS98 and CS402 were 3.5 x 10(4) and 3.6 x 10(3), respectively.     

Isolation and characterization of fenamiphos degrading bacteria

The biological factors responsible for the microbial breakdown of the organophosphorus nematicide fenamiphos were investigated. Microorganisms responsible for the enhanced degradation of fenamiphos were isolated from soil that had a long application history of this nematicide. Bacteria proved to be the most important group of microbes responsible for the fenamiphos biodegradation process. Seventeen bacterial isolates utilized the pure active ingredient fenamiphos as a carbon source. Sixteen isolates rapidly degraded the active ingredient in Nemacur 5GR. Most of the fenamiphos degrading bacteria were Microbacterium species, although Sinorhizobium, Brevundimonas, Ralstonia and Cupriavidus were also identified. This array of gram positive and gram negative fenamiphos degrading bacteria appeared to be pesticide-specific, since cross-degradation toward fosthiazate, another organophosphorus pesticide used for nematode control, did not occur. It was established that the phylogenetical relationship among nematicide degrading bacteria is closer than that to non-degrading isolates.     

Isolation and characterization of acetonitrile utilizing bacteria

Summary Bacteria utilizing high concentrations of acetonitrile as the sole carbon source were isolated and identified asChromobacterium sp. andPseudomonas aeruginosa. Maximum growth was attained after 96 h of incubation andP. aeruginosa grew slightly faster thanChromobacterium sp. The strains were able to grow and oxidize acetonitrile at concentrations as high as 600 mM. However, higher concentrations inhibited growth and oxygen uptake. Degradation studies with (¹⁴C)acetonitrile indicated 57% of acetonitrile was degraded byPseudomonas aeruginosa as compared to 43% byChromobacterium. The isolates utilized different nitrile compounds as carbon substrates.     

甲醇降解菌的分离及性质研究

对氮肥厂活污泥进行驯化筛选得到3株甲醇降解菌,可耐10,000mg/L左右的甲醇浓度,实验得出其最佳生长条件为：pH7-8、温度30℃－35℃、通气,在适宜条件下,对甲醇有较好的降解能力。     

Isolation and characterization of two vibrio-shaped methane-oxidizing bacteria

An enrichment method for, and the isolation of two related vibrio-shaped methane-oxidizing bacteria are described. Their morphological and physiological characteristics are given. As a name for the genus of the organisms Methy lovibrio is proposed.We wish to thank Miss W. E. de Boer and J. van der Toorn of this laboratory for making the photographs. One of the authors (P. J. Steennis) is indebted to the Royal Netherlands Fermentation Industries Ltd., Delft for a grant.     

Isolation and characterization of some new oxalate-decomposing bacteria

Forty-one cultures degrading and assimilating oxalate were isolated from chicken dung. Characterization indicated six different types. One of these belonged to the genusAlcaligenes hitherto never reported to degrade oxalate. Three groups ofPseudomonas strains differed physiologically from strains already known.     

Isolation and characterization of rabbit caecal pectinolytic bacteria

Two hundred and thirty colonies from the caecal contents of six rabbits were picked up and, after a 2-d incubation, were microscopically characterized using Gram staining. Large Gram-negative (34%) and small Gram-negative (30%) irregular rods, Gram-negative (27%) and Gram-positive (8%) cocci were found. Eleven isolates (Bacteroides ovatus (6 strains),B. thetaiotamicron, B. caccae, B. stercoris, B. capillosus andCapnocytophaga ochracea) were identified using commercial tests for measuring their catalase activity, metabolite production,etc., and testing their growth in 20% bile. Bacteria belonging to the genusBacteroides were demonstrated to be the principal pectinolytic organisms in the rabbit caecum.     

Isolation and initial characterization of aerobic chloromethane-utilizing bacteria

Abstract Eight strains of non-methane-utilizing aerobic methylotrophic bacteria able to grow on chloromethane as the carbon and energy source have been isolated. Based on their phenotypic and genomic characteristics the new isolates were classified as Hyphomicrobium spp. (strains CM1, CM2, CM9, CM29, CM35) and Methylobacterium spp. (strains CM4, CM30, CM34). All the strains possessed an inducible yet unknown enzyme that catalyzed conversion of chloromethane to HCl and formaldehyde. The latter was oxidized via formate to CO₂ or assimilated through icl⁺ or icl⁻ variants of the serine pathway.