Arsenic detoxification potential of <Emphasis Type="Italic">aox</Emphasis> genes in arsenite-oxidizing bacteria isolated from natural and constructed wetlands in the Republic of Korea

Arsenic is subject to microbial interactions, which support a wide range of biogeochemical transformations of elements in natural environments such as wetlands. The arsenic detoxification potential of the bacterial strains was investigated with the arsenite oxidation gene, aox genotype, which were isolated from the natural and constructed wetlands. The isolates were able to grow in the presence of 10 mM of sodium arsenite (As(III) as NaAsO₂) and 1 mM of d+glucose. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that these isolated strains resembled members of the genus that have arsenic-resistant systems (Acinetobacter sp., Aeromonas sp., Agrobacterium sp., Comamonas sp., Enterobacter sp., Pantoea sp., and Pseudomonas sp.) with sequence similarities of 81–98%. One bacterial isolate identified as Pseudomonas stutzeri strain GIST-BDan2 (EF429003) showed the activity of arsenite oxidation and existence of aoxB and aoxR gene, which could play an important role in arsenite oxidation to arsenate. This reaction may be considered as arsenic detoxification process. The results of a batch test showed that P. stutzeri GIST-BDan2 (EF429003) completely oxidized in 1 mM of As(III) to As(V) within 25–30 h. In this study, microbial activity was evaluated to provide a better understanding of arsenic biogeochemical cycle in both natural and constructed wetlands, where ecological niches for microorganisms could be different, with a specific focus on arsenic oxidation/reduction and detoxification.     

Removal of arsenic by Acidothiobacillus ferrooxidans bacteria in bench scale fixed-bed bioreactor system

In the present study arsenic contaminated simulated water and groundwater was treated by the combination of biological oxidation of tri-valent arsenite [As (III)] to penta-valent arsenate [As (V)] in presence of Acidothiobacillus ferrooxidans bacteria and its removal by adsorptive filtration in a bioreactor system. This method includes the immobilisation of A.ferrooxidans on Granulated Activated Carbon (GAC) capable of oxidising ferrous [Fe (II)] to ferric [Fe (III)]. The Fe (III) significantly converts the As (III) to As (V) and ultimately removed greater than 95% by the bed of GAC, limestone, and sand. The significant influence of Fe (II) concentration (0.1–1.5?gL^?1), flowrate (0.06–0.18?Lh^?1), and initial As (III) concentration (100–1000?µgL^?1) on the arsenic removal efficiency was investigated. The simulated water sample containing the different concentration of As (III) and other ions was used in the study. The removal of other co-existing ions present in contaminated water was also investigated in column study. The concentration of arsenic was found to be <10?µgL^?1 which is below Maximum Contaminant Level (MCL) as per WHO in treated water. The results confirmed that the present system including adsorptive-filtration was successfully used for the treatment of contaminated water containing As (III) ions.     

Combined use of earthworm (Alma millsoni) and bacterium (Bacillus sp.) improved the bioremediation of spent engine oil contaminated soil

This study was carried out to assess the effectiveness of the combined use of earthworm (Alma millsoni) and bacterium (Bacillus sp.) in the bioremediation of spent engine oil (SEO) contaminated soils. A. millisoni were collected from the Botanical Garden of University of Ibadan, Nigeria. The stock culture of hydrocarbonoclastic Bacillus sp. was used for the bioremediation study. A set-up of eight pots containing 1000?g soil sample and 20?g of cow dung were mixed with 100, 75, 50 and 0?mL SEO respectively. Each of the set up was subjected to bioremediation agents; A. millisoni alone, Bacillus sp alone, A. millisoni and Bacillus sp, no treatment (control) in duplicate. Treatment of 100?ml SEO contaminated soil with combined A. millisoni and Bacillus sp resulted in significantly (P? bacterium > vermi-remediating agents. Earthworms exposed to 100?mLSEO-contaminated soil had higher CAT, SOD, and GPx activities compared to the control. Findings indicated that A. millisoni with Bacillus sp. can synergistically improve bioremediation of SEO contaminated soils.     

Assessment of phenol-degrading ability of Acinetobacter sp. B9 for its application in bioremediation of phenol-contaminated industrial effluents

Successful bioremediation of a phenol-contaminated environment requires application of those microbial strains that have acquired phenol tolerance and phenol-degrading abilities. A newly isolated strain B9 of Acinetobacter sp. was adapted to a high phenol concentration by growing sequentially from low- to high-strength phenol. The acclimatised strain was able to grow and completely degrade up to 14?mM of phenol in 136?h. The degradation rates were found to increase with an increase in the phenol concentration from 2.0 to 7.5?mM. The strain preferred neutral to alkaline pH range for growth and phenol degradation, with the optimum being pH 8.0. The optimum temperature for phenol degradation was found to be in the range of 30–35°C. Transmission electron micrographs showed a disorganised and convoluted cell membrane in the case of phenol-stressed cells, showing a major effect of phenol on the membrane. Enzymatic and gas chromatography-mass spectrometry studies show the presence of an ortho-cleavage pathway for phenol degradation. Efficient phenol degradation was observed even in the presence of pyridine and heavy metals as co-toxicants showing the potential of strain in bioremediation of industrial wastes. Application of strain B9 to real tannery wastewater showed 100% removal of initial 0.5?mM phenol within 48?h of treatment.     

As(V)-reduction to As(III) by arsenic-resistant Bacillus spp. bacterial strains isolated from low-contaminated sediments of the Oliveri-Tindari Lagoon,Italy

Five arsenic-resistant bacterial strains designated MT1, MT2, MT3, V1 and V2 were isolated from sediments of the Oliveri-Tindari Lagoon (Italy), which comprises six small lakes whose sediments contain low arsenic concentrations. Phylogenetic analysis of the 16S rRNA gene sequences assigned them to the genus Bacillus. Bacillus sp. strain MT3 showed higher tolerance to As(III) and As(V), as indicated by minimum inhibitory concentrations of 14 and 135 mmol^?1, respectively. Bacillus sp. strain V1 showed growth inhibition at 14 mmol^?1 in the presence of As(III) and at 68 mmol^?1 in the presence of As(V), whereas the arsenic resistance of Bacillus sp. strain MT1 was 10 and 27 mmol^?1 for As(III) and As(V), respectively. The strains Bacillus spp. MT2 and V2 showed low levels of As(III) and As(V) resistance, as it was unable to grow at concentrations>7 and 14 mmol^?1, respectively. The isolated arsenic-resistant Bacillus spp. strains were able to reduce As(V) to As(III), especially Bacillus spp. strain MT3. This study suggests that the isolated bacterial strains play a role in the arsenic biogeochemical cycle of arsenic-poor sediments in the Oliveri-Tindari Lagoon.     

Distribution of arsenic compounds in Plantaginaceae and Cyperaceae plants growing in contaminated soil

The ability of plant species to accumulate arsenic (As) species in the biomass from As-contaminated soils is variable. Among the plants widely grown at the As-contaminated locations, Plantaginaceae and Cyperaceae families belong to the frequent ones. In this study, the ability of Plantago lanceolata (Plantaginaceae) and three wetland plant species representing the family Cyperaceae (Carex praecox, Carex vesicaria, and Scirpus sylvaticus) naturally occurring in the soils with an elevated As in the Czech Republic were investigated. The plants were cultivated under controlled conditions in an As-contaminated soil reaching 735?mg?kg^?1 of the total As. The total As in plants reached up to 8.3?mg?kg^?1 in leaves, and up to 155?mg?kg^?1 in roots of C. praecox. Dominant As compounds were arsenite and arsenate with a small abundance of dimethylarsinic acid (DMA) in all the plant species. In Cyperaceae, small percentages of arsenobetaine (AB) and arsenocholine (AC) were detected, suggesting the ability of these plants to transform As into less toxic compounds. Moreover, the important role of As(V) sequestration on iron plaque on the root surface of Cyperaceae was confirmed. In this context, root washing with oxalic acid partially disrupted the iron plaque for the better release of arsenate.     

Arsenite oxidation by <Emphasis Type="Italic">Alcaligenes</Emphasis> sp. strain RS-19 isolated from arsenic-contaminated mines in the Republic of Korea

Arsenite [As(III)]-oxidizing bacteria play important roles in reducing arsenic [As] toxicity and mobility in As-contaminated areas. As-resistant bacteria were isolated from the soils of two abandoned mines in the Republic of Korea. The isolated bacteria showed relatively high resistances to As(III) up to 26 mM. The PCR-based 16S rRNA analysis revealed that the isolated As-resistant bacteria were close relatives to Serratia marcescensa, Pseudomonas putida, Pantoea agglomerans, and Alcaligenes sp. Among the five As-resistant bacterial isolates, Alcaligenes sp. strain RS-19 showed the highest As(III)-oxidizing activity in batch tests, completely oxidizing 1 mM of As(III) to As(V) within 40 h during heterotrophic growth. This study suggests that the indigenous bacteria have evolved to retain the ability to resist toxic As in the As-contaminated environments and moreover to convert the species to a less toxic form [e.g., from As(III) to As(V)] and also contribute the biogeochemical cycling of As by being involved in speciation of As.     

Strengthening effects of ammonia nitrogen on the harmless biological treatment of oily sludge

To improve the efficiency of oil degradation and strengthen the harmless treatment of oily sludge, three dominant strains identified as Chryseomicrobium sp. YL2, Gordonia sp. YL3 and Acinetobacter sp. YL5 were isolated from soil near a refinery, and the effects on the bioremediation of the oily sludge from the refinery were investigated. The results showed that the efficiency of oil degradation increased by 31.5% compared with the control when the dominant strains were added to the treatment of oily sludge. Furthermore, the dominant strains could use oil as a carbon source for heterotrophic nitrification–aerobic denitrification. The addition of ammonia nitrogen resulted in a large number of remaining microbes and heightened dehydrogenase activity in the oily sludge, further accelerating oil degradation, mainly for C₁₁ to C₂₅ saturated hydrocarbons, and the oil degradation efficiency increased by 40.8%. After 120 days of bioremediation, the biotoxicity of oily sludge, which was expressed by the equivalent phenol concentration, decreased by 40.0% compared with that of the control, indicating that the addition of ammonia nitrogen enhanced the biodegradation of oil. This method can be used to strengthen the harmless treatment of oily sludge in practical engineering applications.     

Biodegradation kinetics of cymoxanil in aquatic system

A potential method to detoxify pesticides in aquatic system is using bioremediation. In this study, four microorganisms (Pseudomonas sp (EB11), Streptomyces sp. (EB12), Aspergillus niger (EB13) and Trichoderma viride (EB14) were isolated from cucumber leaves previously treated with cymoxanil using enrichment technique. These strains were evaluated for their potential to detoxify cymoxanil in aquatic system at the concentration level of 5×10^?4M. The effect of pH and temperature on the growth ability of the tested strains was also investigated by measuring the intracellular protein and mycelia dry weight for bacterial and fungal strains, respectively. Moreover, the remaining toxicity of cymoxanil after 28 days of incubation with tested strains was evaluated to confirm the complete removal of any toxic materials (cymoxanil and its metabolites). The results showed that the optimum pH for the growth of cymoxanil degrading strains (bacteria and fungi) was 7. A temperature of 30°C appears to be the optimum for the growth of either fungal or bacterial strains. Pseudomonas sp. (EB11) was the most effective strain in cymoxanil degradation followed Streptomyces sp (EB12), Trichoderma viride (EB14) and Aspergillus niger (EB13), with half-lives of 4.33, 9.5, 17.3 and 24.7 days, respectively. The degradation of cymoxanil by bacterial strains was much faster than fungal one. There is no remaining toxicity of cymoxanil detected in aqueous media previously treated with Pseudomonas sp. (EB11) for 28 days. The results suggest that bioremediation by Pseudomonas sp. (EB11) are promising for the detoxification of cymoxanil in aqueous media.     

Effects of salinity on soil bacterial and archaeal community in estuarine wetlands and its implications for carbon sequestration: verification in the Yellow River Delta

Soils from two typical tidal salt marshes with varied salinity in the Yellow River Delta wetland were analysed to determine possible effects of salinity on soil carbon sequestration through changes in soil microbiology. The mean soil respiration (SR) of the salt water–fresh water mixing zone (MZ) was 2.89 times higher than that of the coastal zone (CZ) (4.73 and 1.63?μmol?m^?2?s^?1, respectively, p?Pseudomonas sp. and Limnobacter sp. that might have led to its higher dehydrogenase activity and respiratory rates. Additionally, the CZ possessed more Halobacteria and Thaumarchaeota with the ability to fix CO₂ than the MZ. Significantly lower soil salinity in MZ (4.25?g?kg^?1) was suitable for β-Proteobacteria, but detrimental for Halobacteria compared with CZ (7.09?g?kg^?1, p?相似文献   

Arsenic metabolism in marine bacteria and yeast

Arsenic metabolism was studied for two marine microorganisms, a facultative anaerobic bacterium, Serratia marinorubra, and an obligately aerobic yeast, Rhodotorula rubra. Both were cultivated in media with (⁷⁴As) arsenate (As V), and the products of arsenate metabolism were determined qualitatively. Both the bacterium and the yeast produced arsenite (AS III) and methylarsonic acid [CH₃AsO(OH)₂]. In addition to the foregoing, only the yeast produced dimethylarsinic acid (CH₃)₂AsO(OH) and volatile alkylarsines. In contrast, the bacterium growing anaerobically with cobalamine as a cofactor did not synthesize gaseous forms of arsenic such as methylarsines. Neither organism synthesized arsoniumphospholipids such as those produced by marine phytoplankton or terrestrial fungi. The yeast did not accumulate arsenite, but instead transported some of it into the culture medium and methylated the remainder first to methylarsonic acid and then to dimethylarsinic acid. Finally, the latter compound was methylated further and volatile alkylarsines were formed. In contrast, the bacterium retained all products of arsenate metabolism intracellularly. Both the bacterium and the yeast, therefore, converted relatively toxic arsenate, the most abundant arsenic compound in seawater, to products that were presumably less toxic.     

Biodegradation and phytotoxicity assessment of phenanthrene by biosurfactant-producing Bacillus pumilus 1529 bacteria

ABSTRACT

Phenanthrene is a toxic and mutagenic pollutant that can cause severe environmental and human health issues. The bioremediation of these polyaromatic hydrocarbons (PAHs) is possible with a biosurfactant by enhancing hydrophobicity. In this study, the production of a biosurfactant by Bacillus pumilus 1529 and its effects on the phenanthrene biodegradation pathway were examined. Biosurfactant production was determined using hemolytic activity, emulsification index, and surface tension. For phenanthrene metabolite detection, samples at 0, 7, 14, and 21 incubation days were analysed by gas chromatography-mass (GC-mass) spectrometry. The results showed that Bacillus pumilus 1529 can reduce surface tension to 22.83?±?1.1?mN?m^?1. Furthermore, the GC-mass spectrometry analysis showed that 1-hydroxy-2-naphthoic acid, benzaldehyde, o-phthalic acid, and phenylacetic acid were notable phenanthrene metabolites produced during phenanthrene biodegradation. Biodegraded phenanthrene and its metabolites have a less toxic effect on the germination of safflower seeds than non-biodegraded phenanthrene. The IC50 of phenanthrene on seed germination after biodegradation was increased to approximately 113?mg?L^?1. In general, biodegradation aided by biosurfactant producing bacteria contributed to turning the toxic phenanthrene into less harmful metabolites with lower phytotoxicity effects, indicating that its application in the bioremediation of PAHs is promising.     

Species-level study on arsenic availability from dietary components

Arsenic (As) contaminated water and foodstuffs are of major concern. Samples of drinking–cooking water (n = 50), raw rice (n = 50), common vegetables (eight types), and common pulses (three types) were collected from households in the endemic region. The study found up to 70% As reduction by using safe water for cooking of rice and vegetables. Speciation study reflected more arsenate than arsenite and other organic arsenicals in all the types of samples. Male intake of 293 μg As through drinking water contained 38 μg arsenite and 246 μg arsenate, and female intake of 199 μg As contained 167 μg arsenate and 25 μg arsenite. In cooked rice, 108 μg As contained 69 μg arsenate and 17 μg arsenite with 9 μg dimethylarsonic acid (DMA). Total As consumption from cooked vegetables was 45 μg with 34 and 4 μg of arsenite and arsenate, respectively, and 5 μg of DMA. Data indicate that cooking with As-free water removes arsenic in already contaminated foodstuffs but without interconversion of the As species, from toxic inorganic to less toxic organic forms.     

Bioremediation of heavy metal contaminated medium using Lemna minor,Daphnia magna and their consortium

Single, dual and triple mixtures of totally seven different mixture combinations of the metals Al, Ba and Fe were examined in Lemna minor (L) culture, Daphnia magna (D) culture and in a consortium culture consisting of L. minor and D. magna. In this study: (a) differences in removed metal proportions at the end of 24 and 48?h, (b) differences in removed metal amounts due to cultures, (c) differences in the removed proportions of a metal in distinct mediums and (d) removal correlation of the metals due to cultures were investigated. The study results showed that among the metals Al, Ba and Fe, Al has the most toxic effect on organisms involved in this study. Although similar toxicity results of Al and Fe on test groups were observed, Ba gave different toxicity results on test groups. An overview of the bioremediation results indicates that L. minor removes the metals Al and Fe more successfully than Ba. Different mixture combinations of metals performed dissimilar removal results in the same cultures. According to the correlations analysis for the metals Ba and Fe, a high correlation was recorded between the consortium group and test groups containing only D. magna, r?=?0.88, r?=?0.91, respectively.     

In situ enhanced bioremediation of dichlorvos by a phyllosphere Flavobacterium strain

A bacterium capable of degrading dichlorvos was isolated from the rape phyllosphere and designated YD4. The strain was identified as Flavobacterium sp., based on its phenotypic features and 16S rRNA gene sequence. Strain YD4 was able to utilize dichlorvos as the sole source of phosphorus. In situ enhanced bioremediation of dichlorvos by YD4 was hereafter studied. Chlorpyrifos and phoxim could also be degraded by this strain as the sole phosphorus source. A higher degradation rate of dichlorvos was observed after spraying YD4 onto the surface of rape leaves when compared to the sterilized-YD4 and water-treated samples. The results indicated that pesticide-degrading epiphytic bacterium could become a new way for in situ phyllosphere bioremediation where the hostile niche is unsuitable for other pesticide-degrading bacteria isolated from soil and water.     

Bioremediation of aquaculture wastewater from Mugil cephalus (Linnaeus, 1758) with different microalgae species

Current aquaculture practices have a detrimental impact on the environment, in particular due to the release of high concentration of nitrogen and phosphorus that can induce eutrophication. This study investigates and compares the capacity of three microalgae species Tetraselmis suecica, Isochrysis galbana and Dunaliella tertiolecta, in the bioremediation of grey mullet Mugil cephalus wastewater. The experiment was conducted in batch conditions for 7 days using completely mixed bubble column photobioreactors. After two days, T. suecica and D. tertiolecta were able to remove more than 90% of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorous (DIP), whereas I. galbana removed only 32% and 79% of DIN and DIP, respectively. A higher biomass yield resulted for T. suecica (603?±?34?mg/L, mean?±?SE). This study confirms the potential to employ T. suecica in an Integrated Multi-Trophic Aquaculture system for bioremediation of wastewater and identifies D. tertiolecta as another valid candidate species. Moreover, these species can growth in unsterilized culture media, and this reduces energy consumption, costs and efforts.     

Phylogenetic relationships among species of Calyptogena (Bivalvia: Vesicomyidae) collected around Japan revealed by nucleotide sequences of mitochondrial genes

Phylogenetic relationships among the seven species of deep-sea giant clams Calyptogena (Bivalvia: Vesicomyidae) collected around Japan were examined using parts of nucleotide sequences of mitochondrial genes for cytochrome oxidase I (COI) and cytochrome oxidase III (COIII) and the encoded amino acid sequences. The seven species were C. soyoae (Sagami Bay), C. fausta (Suruga Bay), C. kaikoi (Nankai Trough), C. nautilei (Nankai Trough), C. phaseoliformis (Japan Trench), C. solidissima (Minami-Ensei Knoll, Okinawa Trough) and Calyptogena sp. (Iheya Ridge, Okinawa Trough). A clear phylogenetic split was observed between one group of three species (C. kaikoi, C. phaseoliformis and C. fausta) and the remaining species. This clustering corresponds to the two previously described subgenera within the genus Calyptogena (Calyptogean and Ectenagena) with the exception of the placement of C. nautilei, which had been placed in the subgenus Ectenagena. Genetic distances between two haplotypes of C. soyoae were 0.043 for the COI region and 0.055 for the COIII region, and three amino acid substitutions were detected with the COIII region. Calyptogena sp. from the Iheya Ridge could be distinguished from one of the two haplotypes (type A) of C. soyoae by only a single nucleotide substitution, a result that suggests that Calyptogena sp. of the Iheya Ridge diverged from C. soyoae after the two haplotypes had diverged, and it is now isolated from C. soyoae in Sagami Bay.     

Simultaneous measurements of arsenic and sulfide using diffusive gradients in thin films technique (DGT)

Diffusive gradients in thin films technique (DGT) is a dynamically passive sampling technique which has been applied increasingly to the environmental monitoring field. In the preliminary period, the DGT with zirconium hydroxide-silver iodide as the binding phase (ZrO-AgI DGT) has been developed for the determination of sulfide (S(II)). On this basis, this paper developed its determination method for inorganic arsenite (As(III)) to further realize the simultaneous and high-resolution measurements of labile inorganic As and S(II) in sediments. ZrO-AgI binding gel had a strong ability in adsorbing and fixing As(III), showing a linear increase in the initial 12.5 min. After saturation of S(II) on ZrO-AgI binding gel, the adsorption rate and adsorption capacity of As(III) reduced by 8 and 14%, respectively. A stable elution rate (89.1 ± 2.2%) was obtained by extraction of As(III) on the binding gel using a mixture solution of 1.0 M NaOH and 1.0 M H₂O₂ (1:1). The DGT capacity of As(III) determined by the ZrO-AgI DGT was 23.6 μg cm^?2. DGT uptakes of As(III) were independent of pH (4.0–9.0) and ionic strength (0.01–100 mM), and they did not interfere with each other during the uptake process. Simultaneous measurements of labile As and S(II) in four sediment cores of Taihu Lake (China) with ZrO-AgI DGT showed that they had similarly vertical distributions in the top 16-mm layer in one core and in the whole profile up to the 35 mm depth in two cores. It likely reflected a simultaneous release of As and S(II) in sediments by synchronous reduction of As-hosted oxidized iron and sulfate, respectively. The simultaneous decreases of labile As and S(II) from their co-precipitation (e.g., As₂S₃) were not obvious in deeper sediment layer through the measurement with ZrO-AgI DGT.     

集胞藻(Synechocystis sp. PCC6803)对砷吸收转化特性的初步研究

砷是一种广泛存在于环境中的有毒物质.集胞藻属于单细胞藻类,广泛分布在淡水生态环境中.采用营养液培养的方法探讨了集胞藻(Synechocystis sp.PCC6803)对砷的累积和转化特性.当集胞藻分别暴露于2和100 μM的无机As(Ⅲ)和As(Ⅴ)14 d后,体内的砷形态均以As(Ⅴ)为主,并且在100 μM浓度处...     

In vitro degradation of the herbicide atrazine by soil and wood decay fungi controlled through Elisa technique

The interaction between atrazine, a triazine herbicide, and a series of decay fungi was characterized in terms of biodegradation of the herbicide and its influence on fungal growth. The following fungi were studied: thermophilic cellulolytic (Penicillium sp. 13) and noncellulolytic (Humicola lanuginosa sp. 5 and 12) strains isolated from self‐heated plant composts, mesophilic diphenol oxidase producing strain Mycelia sterilia INBI 2–26, white‐rot fungi Cerrena maxima, Coriolopsis fulvocinerea and Coriolus hirsutus. Competitive enzyme immunoassay was elaborated for detection of atrazine in cultural liquid. During agar plate cultivation the growth of Humicola sp. 5 was promoted by atrazine whereas the growth of Humicola sp. 12 and Penicillium sp. 13 was suppressed whereas M. sterilia INBI 2–26 was not affected by the herbicide. Neither atrazine‐accelerated nor atrazine‐depressed thermophilic strains decomposed atrazine during 21‐day cultivation according to ELISA data. In contrast, white‐rot fungi Coriolus hirsutus, Coriolopsis fuhocinerea and Cerrena maxima degraded nearly 50% of the herbicide in 5‐day submerged cultivation and 80–92% of the herbicide up to the 40th day. The soil strain M. sterilia INBI 2–26 decomposed 70% of atrazine in 17‐day cultivation. The degradation level depended of the time of atrazine introduction to the growing media. The relationships between the degree of atrazine decomposition and laccase and Mn‐peroxidase production were shown.