Oxygen and light effects on the expression of the photosynthetic apparatus in Bradyrhizobium sp. C7T1 strain

Photosynthetic bradyrhizobia are nitrogen-fixing symbionts colonizing the stem and roots of some leguminous plants like Aeschynomene. The effect of oxygen and light on the formation of the photosynthetic apparatus of Bradyrhizobium sp. C7T1 strain is described here. Oxygen is required for growth, but at high concentration inhibits the synthesis of bacteriochlorophyll (BChl) and of the photosynthetic apparatus. However, we show that in vitro, aerobic photosynthetic electron transport occurred leading to ADP photophosphorylation. The expression of the photosynthetic apparatus was regulated by oxygen in a manner which did not agree with earlier results in other photosynthetic bradyrhizobia since BChl accumulation was the highest under microaerobic conditions. This strain produces photosynthetic pigments when grown under cyclic illumination or darkness. However, under continuous white light illumination, a Northern blot analysis of the puf operon showed that, the expression of the photosynthetic genes of the antenna was considerable. Under latter conditions BChl accumulation in the cells was dependent on the oxygen concentration. It was not detectable at high oxygen tensions but became accumulated under low oxygen (microaerobiosis). It is known that in photosynthetic bradyrhizobia bacteriophytochrome photoreceptor (BphP) partially controls the synthesis of the photosystem in response to light. In C7T1 strain far-red light illumination did not stimulate the synthesis of the photosynthetic apparatus suggesting the presence of a non-functional BphP-mediated light regulatory mechanism.     

Effects of buffer capacity on growth,photosynthesis, and solute accumulation of a glycophyte (wheat) and a halophyte (<Emphasis Type="Italic">Chloris virgata</Emphasis>)

Two species with different resistances to alkaline pH, the glycophylic Triticum aestivum (wheat) and the halophilic Chloris virgata, were chosen as test organisms. The salt-alkaline (SA) mixed stress conditions with different buffer capacities (BC) but with the same salt molarities and pH were established by mixing neutral (NaCl, Na₂SO₄), and alkaline salts (NaHCO₃ and Na₂CO₃) in various proportions. Growth, photosynthetic characteristics, and solute accumulation of the seedlings were monitored to test the validity of BC as a decisive index of alkali-stress (AS) intensity in SA mixed stress. At the same salinities and pHs, the relative growth rate, the content of photosynthetic pigments, and net photosynthetic rates of wheat and C. virgata decreased, while Na⁺ content and Na⁺/K⁺ ratios in shoots increased with increasing BC. Hence BC was a true measure of AS intensity at mixed SA stress and the alkali-resistance mechanism of plants was easy to interpret. BC of soil solution is an important parameter for estimating the alkalization degree of salt-alkalized soil.     

Pelodictyon phaeoclathratiforme sp. nov., a new brown-colored member of the Chlorobiaceae forming net-like colonies

A new strain of the green sulfur bacteria was isolated from the monimolimnion of Buchensee (near Radolfzell, Lake Constance region, FRG). Single cells were rod-shaped, nonmotile and contained gas vacuoles. Typical net-like colonies were formed by ternary fission of the cells. As photosynthetic pigments bacteriochlorophylls a, e, isorenieratene and -isorenieratene were present. Sulfide, sulfur and thiosulfate were used as electron donors during anaerobic phototrophic growth. Besides carbon dioxide, acetate and propionate could serve as carbon sources under mixotrophic conditions in the light. Like all other members of the green sulfur bacteria, the new bacterium is strictly anaerobic and obligately phototrophic. The possession of gas vacuoles and the formation of net-like colonies and the guanine plus cytosine content of the DNA (47.9 mol% G+C) are typical characteristics of the genus Pelodictyon. Because of its photosynthetic pigments which differ from those of Pelodictyon clathratiforme, strain BU 1 represents a new species, P. Phaeoclathratiforme sp. nov.     

葡萄糖对小球藻(Chloralla sp. HN08)光合作用和生长的影响

【目的】探讨葡萄糖作为外加碳源对热带海洋小球藻(Chloralla sp.HN08)生物质生产和脂、光合色素、碳水化合物及可溶性蛋白等细胞主要成份含量的影响。【方法】分析比较小球藻HN08在光合自养和兼养(添加10 g/L葡萄糖)2种营养方式下的生长速率、细胞密度、光合放氧速率、油脂相对含量,以及可溶性总糖、淀粉和可溶性蛋白的含量。【结果】结果表明,在光照条件下葡萄糖(10 g/L)能促进小球藻(Chloralla sp.HN08)生长,提高细胞终密度,而异养条件下藻细胞逐渐衰亡。兼养条件下,细胞相对生长速率及细胞终密度分别是自养条件下的6.8倍和1.3倍。兼养藻细胞中可溶性糖、淀粉、油脂含量显著高于(P0.05)光合自养细胞,然而可溶性蛋白质和光合色素含量显著低于(P0.05)光合自养细胞。添加葡萄糖的小球藻液的光饱和点和呼吸速率均高于光自养条件下的细胞,但2种培养条件下藻液的净光合速率无显著差异(P0.05)。【结论】光照条件下,添加葡萄糖可显著提高小球藻HN08相对生长速率和细胞终密度,促进油脂与淀粉的积累。     

镉胁迫下硒对罗汉果组培苗光合特性的影响

实验以罗汉果组培苗为材料,室内栽培在内装市售营养土的塑料盆中,以0、10、50、100、200mg·kg-1浓度镉离子和1mg·kg-1浓度硒处理,培养20d后分析罗汉果幼苗的相关光合生理指标。结果表明:低浓度Cd2+对叶片叶绿素含量、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)影响不大或稍有上升,但高浓度镉离子处理植株叶片的叶绿素含量、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)明显下降;随Cd2+处理浓度的增加,叶片胞间CO2浓度(Ci)呈现上升趋势;加硒则延缓叶绿素下降,促进光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)上升,降低叶片胞间CO2浓度(Ci)。表明高浓度镉离子的毒害导致罗汉果组培苗叶片光合性能受到伤害,从而影响罗汉果幼苗生长。镉硒混合处理反映出硒对镉的毒害有缓解作用。     

On the photosynthetic properties of marine bacterium COL2P belonging to Roseobacter clade

Aerobic anoxygenic phototrophs (AAPs) are prokaryotic microorganisms capable of harvesting light using bacteriochlorophyll-based reaction centres. Marine AAP communities are generally dominated by species belonging to the Roseobacter clade. For this reason, we used marine Roseobacter-related strain COL2P as a model organism to characterize its photosynthetic apparatus, level of pigmentation and expression of photosynthetic complexes. This strain contained functional photosynthetic reaction centres with bacteriochlorophyll a and spheroidenone as the main light-harvesting pigments, but the expression of the photosynthetic apparatus was significantly reduced when compared to truly photoautotrophic species. Moreover, the absence of peripheral light-harvesting complexes largely reduced its light-harvesting capacity. The size of the photosynthetic unit was limited to 35.4 ± 1.0 BChl a molecules supplemented by the same number of spheroidenone molecules. The contribution of oxidative phosphorylation and photophosphorylation was analysed by respiration and fluorometric measurements. Our results indicate that even with a such reduced photosynthetic apparatus, photophosphorylation provides up to three times higher electron fluxes than aerobic respiration. These results suggest that light-derived energy can provide a substantial fraction of COL2P metabolic needs.     

Metabolic recovery of the Antarctic liverwort <Emphasis Type="Italic">Cephaloziella varians</Emphasis> during spring snowmelt

We measured the responses of pigments and chlorophyll a fluorescence parameters of the Antarctic leafy liverwort Cephaloziella varians to snowmelt during austral spring 2005 at Rothera Point on the western Antarctic Peninsula. Although no changes to the concentrations of UV-B photoprotective pigments were detected during snowmelt, chlorophyll and carotenoid concentrations and maximum photosystem (PS)II yield (F _v /F _m) were respectively 88, 60 and 144% higher in the tissues of the liverwort that had recently emerged from snow than in those under a 10 cm depth of snow. A laboratory experiment similarly showed that effective PSII yield increased rapidly within the first 45 min after plants sampled from under snow were removed to an illuminated growth cabinet. The pigmentation and PSII yields of plants during snowmelt were also compared with those of plants in January, during the middle of the growing season at Rothera Point. During snowmelt, plants had lower F _v /F _m values, chlorophyll a/b ratios and concentrations of UV-B photoprotective pigments and carotenoids than during mid-season, suggesting that although there is some recovery of PSII activity and increases in concentrations of photosynthetic pigments during snowmelt, the metabolism of C. varians is restricted during this period.     

Negative Effects of P-Buffering and pH on Photosynthetic Activity of Planktonic Desmid Species

The photosynthetic activities of three planktonic desmid species (Staurastrum brachiatum, Staurodesmus cuspidatus var. curvatus, and Staurastrum chaetoceras) were compared after adaptation to medium enriched with either a 20 mM Na⁺-phosphate (P) or HEPES buffer. Incubations up to 2 d were carried out at pH 6 or 8 under normal air or air enriched with 5 % CO₂. Gross maximum photosynthetic rate (P _max) and growth rate were decreased in both S. brachiatum and Std. cuspidatus at higher pH when using the HEPES buffer and this effect was independent of CO₂ concentration, indicating that pH had an inhibitory effect on photosynthesis and growth in these species. The P-buffer at pH 8 caused a large decrease in P _max and quantum yield for charge separation in photosystem 2 (PS2), compared to HEPES-buffered algae. This effect was very large in both S. brachiatum and Std. cuspidatus, two species characteristic of soft water lakes, but also significant in S. chaetoceras, a species dominant in eutrophic, hard water lakes. The decreased P _max in P-buffer could not be related to a significant increase in cellular P content known to be responsible for inhibition in isolated chloroplasts. Experiments at pH 6 and 8 showed that two conditions, high pH and high Na⁺ concentration, both contributed to the decreased P _max and quantum yield in the desmids. Effects of a P-buffer were less pronounced by using K⁺-P buffer. The use of P-buffer at pH 8 possibly resulted in high irradiance stress in all species, indicated by damage in the PS2 core complex. In the soft water species pH 8 resulted in increased non-photochemical quenching together with a high de-epoxidation state of the xanthophyll cycle pigments.     

Wavelength-specific photosynthetic responses of Halophila johnsonii from marine-influenced versus river-influenced habitats

The seagrass Halophila johnsonii Eiseman grows from the upper intertidal to 3 m depths in habitats ranging from near-marine inlets to tidal riverine. These habitats have distinct optical characteristics, primarily due to variable concentrations of watershed-derived chromophoric dissolved organic matter (CDOM), which increases the attenuation of short-wavelength (blue and UV) light. H. johnsonii contains a suite of flavonoids that are thought to serve as UV-protective pigments (UVP). In this study, photosynthetic responses at specific wavelengths were compared between plants from a river-influenced high-CDOM habitat (Oleta River) and those from an adjacent marine, low-CDOM environment (Haulover Inlet) in Florida. Oxygen flux was used to measure dark respiration and photosynthesis under near-constant radiant energy at nine specific wavelengths from 340 to 730 nm. Riverine plants had higher gross photosynthetic rates and quantum efficiencies than inlet plants at the shortest wavelengths (350, 400 and 450 nm), while inlet plant photosynthetic rates and quantum efficiencies were higher at the two longest wavelengths measured (694 and 730 nm). Riverine plants also exhibited greater variation in photosynthetic responses across the spectrum and more variable pigment levels among replicates. Chlorophyll a and b concentrations were significantly greater in riverine plants suggesting that they were more shade-acclimated compared to the marine populations. Differences in wavelength-specific photosynthetic responses and chlorophyll levels indicate that the riverine plants were blue-shade acclimated. The higher and more variable UVP levels in the riverine population were not consistent with shade acclimation; however, these flavonoid pigments may protect chloroplasts from photodamage during short-term, high intensity irradiance conditions that occur over the course of tidal cycles at this highly fluctuating riverine site.     

Effects of in vitro tissue culture conditions and acclimatization on the contents of Rubisco, leaf soluble proteins, photosynthetic pigments, and C/N ratio

The levels of two subunits of chloroplast ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), total soluble proteins, carbon and leaf nitrogen content, and photosynthetic pigments in various plants (avocado, oak, olive, and strawberry) grown in vitro and ex vitro were analysed. Compared to ex vitro grown plants, micropropagated avocado, oak, and strawberry showed a markable decrease in large subunit Rubisco. However, the small subunit only decreased in strawberry and oak. Contrary to this, olive did not reveal any difference in the level of either subunit. The C/N ratio increased significantly in in vitro grown plants, except in the case of olive, where an opposite behaviour was found. Leaf chlorophyll concentration on unit mass basis was higher in all the in vitro plants than in those of greenhouse- grown plants. Only avocado plantlets showed a statistically significant decrease in total soluble proteins. Further, overall data suggest that in vitro cultural conditions have a species-specific influence on large and small subunits of Rubisco, independent of the protein, chlorophyll, or nitrogen level.     

Carotenoid composition of peridermal twigs does not fully conform to a shade acclimation hypothesis

The photosynthetic pigments of twigs in five tree and shrub species possessing chlorenchyma under a well developed, stomata-less, and highly photon absorptive periderm were analysed and compared to those of the corresponding canopy leaves. We asked whether the unavoidable shade acclimation of corticular chlorenchyma results in photosynthetic pigment complements typically found in shade leaves. As expected, chlorophyll (Chl) a/b ratios in twigs were consistently low. However, carotenoid (Car) analysis did not confirm the initial hypothesis, since twigs generally contained increased Chl-based pool sizes of the xanthophyll cycle components. The contents of photo-selective neoxanthin and lutein were high as well. Yet, -carotene content was extraordinarily low. In addition, twigs retained high pre-dawn ratios of the deepoxidized antheraxanthin and zeaxanthin, although environmental conditions were not pre-disposing for such a state. The unexpected Car composition allows the conclusion that other micro-environmental conditions within twigs (hypoxia, increased red to blue photon ratios, and extremely high CO₂ concentrations) are more important than shade in shaping the Car profiles.This revised version was published online in March 2005 with corrections to the page numbers.     

Properties of Photosynthetic Bacteria in Anisotropic Rigid Matrix and in Suspension

The photosynthetic bacteria (Rhodospirillum rubrum, Synechococcus and Anabaena variabilis) as well as their fragments embedded in isotropic and anisotropic polymer film were investigated. The orientation of photosynthetic pigments inside these organisms was compared, on the basis of the polarised absorption and fluorescence spectra, with the macroscopic orientation of investigated objects seen under microscope. The anisotropy of fluorescence was much higher than anisotropy of absorption. It showed strong influence of the photoselection by polarised radiation on the various bacterial chromophores exhibiting different orientations in the cells and various yields of fluorescence. The dimensions of cells were investigated on the basis of their photographs and by the scattering of the monochromatic radiation.     

Photosynthetic pigments and photosynthetic products of endophyte-infected and endophyte-free Lolium perenne L. under drought stress conditions

Endophyte-infected (EI) seeds of Lolium perenne L. were used to attain endophyte-free (EF) population by heating the seeds at 43°C for 15 min and then 57°C for 25 min. Relative water content (RWC), chlorophyll, soluble sugar and starch content of EI and EF populations under normal and drought stress conditions were compared to investigate the effect of endophyte infection on the host plant. Under severe stress, RWC of EI leaf was significantly higher than that of EF leaf, i.e. EI plants took more advantages over EF plants in water-holding ability. Under mild stress, endophyte could enhance soluble sugars in host plants to improve their osmotic ability. With stress intensification, the improvement of endophyte no longer existed, and more photosynthetic products (such as starch) accumulated in EI plants to survive through the undesirable conditions. In the next spring, EI populations will recover more rapidly than EF populations. The biomass of a population is closely related to its photosynthesis. Under severe stress, EI population significantly accumulated more biomass than EF population. As far as photosynthetic pigments were concerned, contents of Chla, Chlb and Car of EI plants were close to those of EF plants, which suggested that endophyte infection didn’t alleviate photosynthetic pigments from being destroyed by drought stress, and endophyte might improve photosynthesis ability of its host plant in other ways. __________ Translated from Acta Ecologica Sinica, 2005, 25 (2) [译自: 生态学报, 2005, 25(2)]     

Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria (Chlorobi) and the filamentous anoxygenic phototrophic bacteria (Chloroflexales), are otherwise quite different, both physiologically and phylogenetically. This review summarizes how genome sequence information facilitated studies of the biosynthesis and function of the photosynthetic apparatus and the oxidation of inorganic sulfur compounds in two model organisms that represent these taxa, Chlorobium tepidum and Chloroflexus aurantiacus. The genes involved in bacteriochlorophyll (BChl) c and carotenoid biosynthesis in these two organisms were identified by sequence homology with known BChl a and carotenoid biosynthesis enzymes, gene cluster analysis in Cfx. aurantiacus, and gene inactivation studies in Chl. tepidum. Based on these results, BChl a and BChl c biosynthesis is similar in the two organisms, whereas carotenoid biosynthesis differs significantly. In agreement with its facultative anaerobic nature, Cfx. aurantiacus in some cases apparently produces structurally different enzymes for heme and BChl biosynthesis, in which one enzyme functions under anoxic conditions and the other performs the same reaction under oxic conditions. The Chl. tepidum mutants produced with modified BChl c and carotenoid species also allow the functions of these pigments to be studied in vivo.     

Investigations on the phototactic orientation of Anabaena variabilis

Phototaxis of the blue-green alga Anabaena variabilis was studied using both population method and observation of single trichomes by microscope. The trichomes react positively at low and negatively at high illuminance. The inversion point lies at about 1000 1x. The action spectrum of positive phototaxis indicates that the photosynthetic pigments chlorophyll a, C-phycocyanin and allo-phycocyanin are involved in the absorption of the active light. The same range of wavelengths is active in negative phototaxis, but in addition, wavelengths between 500 and 560 nm and between 700 and 750 nm are also effective. Obviously pigments of unknown chemical nature are sharing in light absorption. Two alternatives are discussed. Since inhibitors of photosynthesis such as DCMU and DBMIB do not affect phototactic orientation, a direct coupling of phototaxis with photosynthesis can be excluded.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - DBMIB Dibromothymoquinone (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone) Presented in part at the International Symposium on Photosynthetic Prokaryotes: August 22–28, 1976, Dundee, Scotland     

铝胁迫对木荷幼苗光合特性的影响及添加盐基阳离子和磷的调节作用

为探讨铝(Al)胁迫对木荷(Schima superba)幼苗光合特征的影响,采用营养液水培的方法,对铝(Al)胁迫下木荷幼苗的光合响应及盐基阳离子(BC)和磷(P)的调节作用进行了研究。结果表明,在低浓度Al(0.25 mmol L–1)处理下,木荷幼苗的光合色素(Chl a、Chl b、Car)含量、光合作用参数(P n、g s、WUE、C i/C a)以及光响应特征参数(P max、AQY、R d、LSP)均呈下降趋势,添加BC或同时添加BC和P均能缓解上述参数的降低。中、高浓度Al(0.75、1.50 mmol L–1)处理,除光合色素含量呈增加趋势外,光合作用参数、光响应特征参数均下降,且下降幅度随Al浓度的升高而增大,添加P比添加BC更能有效缓解Al胁迫对木荷幼苗的影响。这揭示了BC、P在缓解木荷Al胁迫的相对重要性。     

18O and mass spectrometry in chlorophyll research: Derivation and loss of oxygen atoms at the periphery of the chlorophyll macrocycle during biosynthesis,degradation and adaptation

Chlorophylls, magnesium-containing tetrapyrrolic pigments of photosynthesis, are widely-distributed in Nature and participate in both light harvesting and in the transduction of light energy to chemical energy for the photosynthetic fixation of carbon dioxide. We briefly discuss the extensive role of various isotopic labelling techniques in elucidating the pathway of tetrapyrrole-pigment biosynthesis and we acknowledge the classic and meticulous research of David Shemin who, approximately 50 years ago, introduced isotopic tracer techniques with ¹⁵N and ¹⁴C isotopes to study the biosynthesis of the carbon/nitrogen macrocycle of haem, an iron tetrapyrrole. The main focus of this review is the application of mass spectrometry and ¹⁸O labelling to the study of the incorporation of oxygen atoms from molecular oxygen or water into the periphery of the chlorophyll macrocycle during biosynthesis and their loss during degradation and light acclimation. In particular, we review the mechanism of formation of the isocyclic ring of chlorophylls, in higher plants, green algae and various photosynthetic bacteria, which concomitantly incurs formation of the 13¹-oxo group that is present in all photosynthetically-active chlorophylls. In addition we discuss the formation of the ubiquitous 13³- and 17³-carboxyl groups and also the formation of the 7-formyl group of chlorophyll b and the 3-acetyl group of bacteriochlorophyll a. This revised version was published online in June 2006 with corrections to the Cover Date.     

Solar energy conversion efficiencies in photosynthesis: Minimizing the chlorophyll antennae to maximize efficiency

The theoretical maxima of solar energy conversion efficiencies and productivities in oxygenic photosynthesis are evaluated. These are contrasted with actual measurements in a variety of photosynthetic organisms, including green microalgae, cyanobacteria, C4 and C3 plants. Minimizing, or truncating, the chlorophyll antenna size of the photosystems can improve photosynthetic solar energy conversion efficiency and productivity up to 3-fold. Generation of truncated light-harvesting chlorophyll antenna size (tla) strains, in all classes of photosynthetic organisms would help to alleviate excess absorption of sunlight and the ensuing wasteful dissipation of excitation energy, and to maximize solar-to-product energy conversion efficiency and photosynthetic productivity in high-density mass cultivations. The tla concept may find application in the commercial exploitation of microalgae and plants for the generation of biomass, biofuels, chemical feedstocks, as well as nutraceuticals and pharmaceuticals.     

Characterization of a new platelet-forming purple sulfur bacterium,Amoebobacter pedioformis sp. nov.

The dominant purple sulfur bacterium of a reddish-colored waste water pond near Taichung, Taiwan, was isolated in pure culture, strain CML2. Individual cells were nearly spherical, nonmotile, and contained in their peripheral parts was vacuoles that appeared like elongated, curved tubes. Four to sixteen cells formed platelet-like aggregates reminiscent of Thiopedia rosea. The intracellular photosynthetic membrane system of the cells was of vesicular type; the photosynthetic pigments consisted of bacteriochlorophyll a and spirilloxanthin as the major carotenoid. The color of cell suspensions was pink to rosered. Under anaerobic conditions photolithoautotrophic growth occurred with sulfide, elemental sulfur or thiosulfate; sulfur globules were stored as an intermediary oxidation product. In the presence of sulfide, acetate, lactate and pyruvate were photoassimilated; strain CML2 lacked assimilatory sulfate reduction. Fastest photoautotrophic growth (11 h doubling time) was obtained at pH 7.5, 35°C and a light intensity of about 1000 lux (tungsten lamp). Chemolithoautotrophic growth in the dark was possible under reduced oxygen partial pressure with reduced sulfur compounds as respiratory substrates. The DNA base composition of strain CML2 was 65.5 mol% G+C. Strain CML2 is described as type strain of a new species, Amoebobacter pedioformis sp. nov., in the family Chromatiaceae.     

Production of (<Emphasis Type="Italic">R</Emphasis>)-ethyl-3,4-epoxybutyrate by newly isolated <Emphasis Type="Italic">Acinetobacter baumannii</Emphasis> containing epoxide hydrolase

Several new microorganisms have been isolated from soil samples with high epoxide hydrolase activity toward ethyl 3,4-epoxybutyrate. Screening was performed by enrichment culture on alkenes as sole carbon source, followed by chiral gas chromatography. Eight strains were discovered with enantioselectivity from moderate to high level and identified as bacterial and yeast species. Cells were cultivated under aerobic condition at 30°C using glucose as carbon source and resting cells were used as biocatalysts for kinetic resolution of ethyl 3,4-epoxybutyrate. Among isolated microorganisms, Acinetobacter baumannii showed highest enantioselectivity for (S)-enantiomer, resulting in (R)-ethyl-3,4-epoxybutyrates (>99%ee, 46% yield). It is the first report on the fact that epoxide hydrolases originating from bacterial species of A. baumannii was applied to kinetic resolution of ethyl 3,4-epoxybutyrate in order to obtain enantiopure high-value-added (R)-ethyl-3,4-epoxybutyrate.