Removal of methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide from contaminated air by Thiobacillus thioparus TK-m.

Methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide were efficiently removed from contaminated air by Thiobacillus thioparus TK-m and oxidized to sulfate stoichiometrically. More than 99.99% of dimethyl sulfide was removed when the load was less than 4.0 g of dimethyl sulfide per g (dry cell weight) per day.     

Degradation of hydrogen sulfide by Xanthomonas sp. strain DY44 isolated from peat.

Xanthomonas sp. strain DY44, capable of degrading H2S, was isolated from dimethyl disulfide-acclimated peat. This bacterium removed H2S either as a single gas or in the presence of the sulfur-containing compounds methanethiol, dimethyl sulfide, and dimethyl disulfide. The maximum specific H2S removal rate, obtained in the late stationary phase, was 3.92 mmol g of dry cells-1 h-1 (6.7 x 10(-16) mol cell-1 h-1) at pH 7 and 30 degrees C through a batch experiment in a basal mineral medium. Since Xanthomonas sp. strain DY44 exhibited no autotrophic growth with H2S, the H2S removal was judged not to be a consequence of chemolithotrophic activity. By using X-ray photoelectron spectroscopy, the metabolic product of H2S oxidation was determined to be polysulfide, which has properties very similar to those of elemental sulfur. Autoclaved cells (120 degrees C, 20 min) did not show H2S degradation, but cells killed by gamma-irradiation and cell extracts both oxidized H2S, suggesting the existence of a heat-labile intracellular enzymatic system for H2S oxidation. When Xanthomonas sp. strain DY44 was inoculated into fibrous peat, this strain degraded H2S without lag time, suggesting that it will be a good candidate for maintaining high H2S removability in the treatment of exhaust gases.     

Degradation of hydrogen sulfide by Xanthomonas sp. strain DY44 isolated from peat.

Xanthomonas sp. strain DY44, capable of degrading H2S, was isolated from dimethyl disulfide-acclimated peat. This bacterium removed H2S either as a single gas or in the presence of the sulfur-containing compounds methanethiol, dimethyl sulfide, and dimethyl disulfide. The maximum specific H2S removal rate, obtained in the late stationary phase, was 3.92 mmol g of dry cells-1 h-1 (6.7 x 10(-16) mol cell-1 h-1) at pH 7 and 30 degrees C through a batch experiment in a basal mineral medium. Since Xanthomonas sp. strain DY44 exhibited no autotrophic growth with H2S, the H2S removal was judged not to be a consequence of chemolithotrophic activity. By using X-ray photoelectron spectroscopy, the metabolic product of H2S oxidation was determined to be polysulfide, which has properties very similar to those of elemental sulfur. Autoclaved cells (120 degrees C, 20 min) did not show H2S degradation, but cells killed by gamma-irradiation and cell extracts both oxidized H2S, suggesting the existence of a heat-labile intracellular enzymatic system for H2S oxidation. When Xanthomonas sp. strain DY44 was inoculated into fibrous peat, this strain degraded H2S without lag time, suggesting that it will be a good candidate for maintaining high H2S removability in the treatment of exhaust gases.     

Removal of methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide from contaminated air by Thiobacillus thioparus TK-m

Methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide were efficiently removed from contaminated air by Thiobacillus thioparus TK-m and oxidized to sulfate stoichiometrically. More than 99.99% of dimethyl sulfide was removed when the load was less than 4.0 g of dimethyl sulfide per g (dry cell weight) per day.     

Micromonospora siamensis sp. nov., isolated from Thai peat swamp forest

Morphological and chemotaxonomic characterization of actinomycete strain TT2-4T isolated from peat swamp forest soil in Pattaloong Province, Thailand, clearly demonstrated that this strain belongs to the genus Micromonospora. 16S rDNA sequence analysis for the strain supported the assignment of the strain to the genus Micromonospora and the similarity value of sequences between this strain and the closely related species, Micromonospora mirobrigensis was 99.1%, and M. carbonacea and M. matsumotoense were 98.8%. The DNA-DNA hybridization result and some physiological and biochemical properties indicated that strain TT2-4T was distinguished from the phylogenetically closest relatives. Based on these genotypic and phenotypic data, strain TT2-4T merits a new species in the genus Micromonospora and the name Micromonospora siamensis sp. nov. is proposed for the strain. The type strain is strain TT2-4T (=JCM 12769T =PCU 266T =TISTR 1554T).     

Isolation and characterization of sulphur-oxidizing Thiomonas sp. and its potential application in biological deodorization

AIMS: To isolate and characterize a sulphur-oxidizing bacterial strain from activated sludge and to evaluate its potential application in biological deodorization. METHODS AND RESULTS: A dominant sulphur-oxidizing bacterial strain, designated as strain SS, was isolated from an enrichment culture using thiosulphate as a sole energy source and CO2 as a sole carbon source. The cells of this organism were aerobic, rod-shaped, Gram-negative and motile. Strain SS could grow autotrophically, heterotrophically as well as mixotrophically. Autotrophic growth was observed at pH values ranging from 2.3 to 9.0. Phylogenetic analyses revealed that strain SS belonged to Group 1 of the genus Thiomonas, closely related to Thiomonas perometabolis and Thiomonas intermedia. The thiosulphate oxidation rates of strain SS at different pH values were evaluated in terms of oxygen uptake using a Micro-Oxymax respirometer. The results showed that the maximum oxidation rate of 5.65 mg l(-1) h(-1) occurred at 56 h of growth and pH 6.0. Continuous H2S removal study demonstrated that strain SS could remove more than 99% of H2S when the inlet concentration was below 58.6 ppm. Further increase of the inlet concentration to 118 ppm gave rise to a decline in the removal efficiency to ca 90%. CONCLUSIONS: The strong acidification of the culture medium during the later period could result in the deterioration of the growth activity and the metabolism activity of strain SS. In practical application, the problems caused by the end-product inhibition and the acidification can be alleviated by periodical replacement of culture medium with fresh medium. Given the physiological flexibility and the ability to remove H2S rapidly and efficiently, strain SS could be a good 'deodorizing' candidate. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first time that Thiomonas species has been reported for biological deodorization application.     

Thiobacillus acidophilus sp. nov.; isolation and some physiological characteristics.

After a brief exposition to glucose, Thiobacillus acidophilus was isolated from a culture of iron-grown T. ferrooxidans. Physicochemical analysis of its DNA showed a G+C content of 62.9-63.2%. The new isolate grows best at 25-30 degrees C and at pH 3.0. Growth is possible between pH 1.5 and 6.0. Thiobacillus acidophilus is apparently strictly aerobic. Ammonium salts are the only suitable source of nitrogen. The bacterium is a facultative autotroph. In addition to elemental sulfur, it obtains energy from organic compounds such as D-glucose, D-galactose, D-fructose, D-mannitol, D-xylose, D-ribose, D-arabinose, L-arabinose, sucrose, sodium citrate, malic acid,dl-aspartic acid, and dl-glutamic acid. Thiobacillus acidophilus possesses the key enzymes of the tricarboxylic acid (TCA) cycle including NAD-and NADP-linked isocitric dehydrogenase and alpha-ketoglutarate dehydrogenase, and the key enzymes of the hexose monophosphate pathway (glucose-6-phosphate and 6-phosphogluconate dehydrogenase, and fructose 1,6-diphosphate aldolase). NADH oxidase has been found in particulate fraction of extracts. Rhodanese and thiosulfate oxidase have also been detected.     

Characteristics of hydrogen sulfide removal in a carrier-packed biological deodorization system

The relationship between the characteristics of carriers in a carrier-packed biological deodorization (CPBD) reactor and the efficiency of H(2)S removal was studied. From the result of a deodorization experiment using three different carriers (each of which obtained a high level of H(2)S removal), the best carrier was cylindrical and the surface and inside of the carrier had macro pores (about 1mm in diameter). The carrier also had large porosity and surface area. Each of these characteristics, with the exception of the large surface area, corresponded to the characteristics that resulted in a high discharge efficiency of sulfuric acid. A deodorization experiment using two carriers that differed only in size showed that K(G)a was a very important operating parameter of the apparatus. Therefore, the size of the carrier should be as small as possible within certain technical limitations.     

Breakdown of dimethyl sulphide by mixed cultures and by Thiobacillus thioparus

Abstract Dimethyl sulphide (DMS) was degraded by acclimatized activated sludge and by a mixed culture of Thiobacillus thioparus TK-1 and Pseudomonas sp. AK-2. While both these organisms persisted in stable co-culture on DMS, it was found that T. thioparus TK-1 and the derived strain TK-m grew in pure culture on DMS, and oxidized DMS with an apparent K _m of 4.5 × 10⁻⁵ M. During growth, all the DMS-sulphur was oxidized stoichiometrically to sulphate but no methanol was detected in pure cultures of TK-m. DMS-carbon was probably converted to CO₂, since the fixation of ¹⁴CO₂ was progressively diluted during growth of a culture on ¹⁴CO₂ and DMS. Growth yields were consistent with autotrophic growth, dependent on the oxidation of the methyl residues to CO₂ (probably with formaldehyde as a first intermediate) and the sulphide to sulphate. The organism thus appears to exhibit a mixture, from the one substrate, of chemolithotrophic and methylotrophic energy generation supporting autotrophic growth with CO₂ fixation.     

Removal of dimethyl sulfide,methyl mercaptan,and hydrogen sulfide by immobilized Thiobacillus thioparus TK-m

Cells of Thiobacillus thioparus TK-m were immobilized on cylindrical porous polypropylene pellets (5 mmφ × 5 mm) which were packed in an acrylic cylinder of 50 mm inner diameter up to the height of 800 mm. When a sulfur-containing malodorous gas was charged to this packed tower at the superficial velocity of 0.1 m/s, maximum loading capacity (mmol/l·d) for a malodorous gas to attain the removal rate of 95% or more was: 3.65 for dimethyl sulfide, 8.74 for methyl mercaptan, and 17.36 for hydrogen sulfide. At this time, the inlet concentration (μl/l) of the malodorous compound was: 7.44 for dimethyl sulfide, 17.8 for methyl mercaptan, and 35.4 for hydrogen sulfide. For every compound, higher loading resulted in greater removal quantities. The removal rate of dimethyl sulfide was not overly affected by the presence of a large amount of easily decomposable hydrogen sulfide.     

Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide,methanethiol and dimethyl sulfide in various biological matrices

This review deals with the measurement of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (–SH) group and appear in the free gaseous form, in the acid-labile form and in the dithiothreitol-labile form. Dimethyl sulfide is a neutral molecule and exists only in the free form. The foul odor of these sulfur volatiles is a striking characteristic and plays a major role in bad breath, feces and flatus. Because sulfur is a biologically active element, the biological significance of the sulfur volatiles are also highlighted. Despite its highly toxic properties, hydrogen sulfide has been lately recommended to become the third gasotransmitter, next to nitric oxide and carbon monoxide, based on high concentration found in healthy tissues, such as blood and brain. However, there is much doubt about the reliability of the assay methods used. Many artifacts in the sulfide assays exist. The methods to detect the various forms of hydrogen sulfide are critically reviewed and compared with findings of our group. Recent findings that free gaseous hydrogen sulfide is absent in whole blood urged the need to revisit its role as a blood-borne signaling molecule.     

Removal of uranium by an exopolysaccharide from Pseudomonas sp.

Summary Accumulation of uranium (U) is reported for isolated exopolysaccharide produced by Pseudomonas sp. EPS-5028. A maximum uptake of 96 g U/mg polymer was observed. In contrast, the maximum accumulation of uranium by deacylated polysaccharide was 46 g/mg. This metal-complexing capacity observed suggests that the anionic reactive sites on the structure could be responsible for this activity. Metal uptake was affected by pH and was not affected by temperature. Expolysaccharide from Pseudomonas sp. EPS-5028 obeyed the Freundlich isotherm indicating single layer adsorption. Offprint requests to: F. Congregado     

感染瓜实蝇的曲霉菌及其生物学特性

从海南自然发病死亡的瓜实蝇上分离获得2株高毒力的真菌BC-D1和BC-212,经形态学和ITS序列鉴定结果表明, BC-D1为黄曲霉Aspergillus flavus,BC-212为溜曲霉Aspergillus tamarii。室内毒力测定结果发现：菌株BC-D1和BC-212对瓜实蝇成虫均有很高毒力,而对卵、幼虫及蛹的毒力较低。接种8d后成虫的平均死亡率分别为73.5%和85.1%,卵、幼虫及蛹的死亡率均低于50%。两株菌对黄粉虫、斜纹夜蛾及蚜虫的致病率均很低。生物学特性测定,两菌株具有生长速度快、产孢量大的特性,最适合生长的温度范围为30-35℃;在不同营养成分的培养基上,菌株生长速率、产孢量及菌落颜色存在较大差异。     

Micromonosporin A, a novel 24-membered polyene lactam macrolide from Micromonospora sp. isolated from peat swamp forest

A novel 24-membered polyene lactam macrolide, micromonosporin A (=(3E,5E,7Z,15E,17E,19E,21E)-9,11,13-trihydroxy-14,19,24-trimethyl-1-azacyclotetracosa-3,5,7,15,17,19,21-heptaen-2-one; 1) was isolated from the actinomycete, Micromonospora sp. strain TT1-11, which was isolated from a very acidic peat swamp forest.     

Fermentation of methanethiol and dimethylsulfide by a newly isolated methanogenic bacterium

From dilution series in defined mineral medium, a marine iregular coccoid methanogenic bacterium (strain MTP4) was isolated that was able to grow on methanethiol as sole source of energy. The strain also grew on dimethylsulfide, mono-, di-, and trimethylamine, methanol and acetate. On formate the organism produced methane without significant growth. Optimal growth on MT, with doubling times of about 20 h, occurred at 30°C in marine medium. The isolate required p-aminobenzoate and a further not identified vitamin. Strain MTP4 had a high tolerance to hydrogen sulfide but was very sensitive to mechanical forces or addition of detergents such as Triton X-100 or sodium dodecylsulfate. Methanethiol was fermented by strain MTP4 according to the following equation:

Characterization of Thiobacillus thioparus isolated from an activated sludge bioreactor used for hydrogen sulfide treatment

AIMS: To compare Thiobacillus thioparus population dynamics in a control and a test activated sludge (AS) bioreactor, used for hydrogen sulfide (H(2)S) degradation. METHODS AND RESULTS: Denaturing gradient gel electrophoresis (DGGE) was used to confirm the presence of T. thioparus, and real-time PCR was used to quantify the level of this bacterium in the AS samples. The DGGE analysis showed a band for T. thioparus in all samples, with the band being more prominent in the test sample with H(2)S diffusion. It also showed that although a change occurred in the diversity of the microbial population in the test sludge after 6 weeks of H(2)S diffusion, the microbial community structure of the test and control was still similar. Thiobacillus thioparus-specific PCR primers confirmed that 50% of the isolates from both the test and control bioreactors were T. thioparus. The thiobacilli population became more efficient at degrading the diffused H(2)S. This increase in efficiency was confirmed by a significant increase in the number of isolates from the test sludge compared with those from the control sludge, when they were grown in a thiosulfate-rich liquid medium. CONCLUSIONS: It was concluded that the use of AS process for H(2)S removal encourages the population of T. thioparus to increase even at times when the total biomass concentration shows a decrease. SIGNIFICANCE AND IMPACT OF THE STUDY: The research results give an insight into the dynamics of the microbial population in an AS pilot plant used in a dual role, to treat the wastewater and H(2)S.     

Paenibacillus frigoriresistens sp. nov., a novel psychrotroph isolated from a peat bog in Heilongjiang, Northern China

A novel cold-resistant bacterium, designated YIM 016^T, was isolated from a peat bog sample collected from Mohe County, Heilongjiang Province, Northern China and its taxonomic position was investigated using a polyphasic approach. The strain was Gram-positive, aerobic, endospore-forming, motile and rod-shaped. Phylogenetic analyses based on the 16S rRNA gene sequence clearly revealed that strain YIM 016^T is a member of the genus Paenibacillus. The strain is closely related to Paenibacillus alginolyticus DSM 5050^T, Paenibacillus chondroitinus DSM 5051^T and Paenibacillus pocheonensis Gsoil 1138^T with similarities of 99.0 %, 97.0 % and 96.3 %, respectively. Meanwhile, the low DNA–DNA relatedness levels between strain YIM 016^T and its closely related phylogenetic neighbours demonstrated that this isolate represents a new genomic species in the genus Paenibacillus. Phenotypic and chemotaxonomic tests showed that growth of strain YIM 016^T occurred at 4–37 °C, pH 6.0–8.0 and with a NaCl tolerance up to 0.5 % (w/v). The peptidoglycan contained meso-diaminopimelic acid, alanine and glutamic acid. The whole-cell hydrolysates mainly contained glucose, galactose and ribose. The predominant menaquinone was MK-7 and the major fatty acids were anteiso-C_15:0 and iso-C_16:0. The DNA G+C content of strain YIM 016^T was 51.7 mol %. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, strain YIM 016^T could be clearly distinguished from other species of the genus Paenibacillus. It is therefore concluded that strain YIM 016^T represents a novel species in the genus Paenibacillus, for which the name Paenibacillus frigoriresistens sp. nov. is proposed. The type strain is YIM 016^T (= CCTCC AB 2011150^T = JCM 18141^T).