Nicotine degradation by two novel bacterial isolates of <Emphasis Type="Italic">Acinetobacter</Emphasis> sp. TW and <Emphasis Type="Italic">Sphingomonas</Emphasis> sp. TY and their responses in the presence of neonicotinoid insecticides

Two novel nicotine-degrading bacterial strains were isolated from tobacco waste and identified as Acinetobacter sp. TW and Sphingomonas sp. TY based on morphology, physiological and biochemical tests, Biolog analysis and 16S rDNA sequencing. The 16S rDNA sequences have been deposited in GenBank under the accession numbers FJ753401 for TW and FJ754274 for TY. The best culture conditions for nicotine degradation were 25–37°C and pH 7.0–8.0 for strain TW and 25–30°C and pH 6.0–7.0 for strain TY. Under the best conditions, the cell growth and nicotine-degradation kinetics of the two isolates were assessed, and 1.0 g/l nicotine was completely degraded within 12 and 18 h for TW and TY, respectively. Moreover, the presence of four widely-used commercial neonicotinoid insecticides in the medium had no effects on nicotine degradation by TW; among the four tested neonicotinoids, only thiamethoxam significantly delayed nicotine degradation by TY. TW and TY were also able to degrade selected neonicotinoids. This is the first report of nicotine degradation by Acinetobacter sp. and Sphingomonas sp. This study showed that these two newly isolated bacteria may be suitable for the disposal of tobacco waste and the reduction of nicotine in tobacco leaves.     

Degradation of Microcystin-RR by Sphingomonas sp. CBA4 isolated from San Roque reservoir (Córdoba – Argentina)

We report the aerobic biodegradation of Microcystin-RR (MC-RR) by a bacterial strain isolated from San Roque reservoir (Córdoba – Argentina). This bacterium was identified as Sphingomonas sp. (CBA4) on the basis of 16S rDNA sequencing. The isolated strain was capable of degrading completely MC-RR (200 μg l⁻¹) within 36 h. We have found evidence that MC-RR biodegradation pathway by this Sphingomonas sp. strain would start by demethylating MC-RR, affording an intermediate product, which is finally biodegraded by this strain within 72 h. Our results confirm that certain environmental bacteria, living in the same habitat as toxic cyanobacteria, have the capability to perform complete biodegradation of MC, leading to natural bioremediation of waterbodies. The bacterium reported here presents genetic homologies with other strains that degrade MC-LR. However, initial demethylation of MC-RR has been not described previously, raising questions on the probable presence of different biodegradation pathways for different MC variants.     

Synergism of VAM and Rhizobium on Production and Metabolism of IAA in Roots and Root Nodules of Vigna Mungo

A novel Acinetobacter strain, Ud-4, possessing a strong capacity to degrade edible, lubricating, and heavy oil was isolated from seawater in a fishing port located in Toyama, Japan. It was identified by morphological and physiological analyses and 16S rDNA sequencing. This strain could utilize five types of edible oils (canola oil, olive oil, sesame oil, soybean oil, and lard), lubricating oil, and C-heavy oil as the sole carbon source for growth in M9 medium. The strain grew well and heavily degraded edible oils in Luria–Bertani medium during a 7-day culture at 25°C; it also degraded all kinds of oils in artificial seawater medium for marine bacteria. Furthermore, this strain was capable of degrading almost all C10–C25 n-alkanes in C-heavy oil during a 4-week culture. Oligonucleotide primers specific to two catabolic genes involved in the degradation of n-alkanes (Acinetobacter sp. alkM) and triglyceride (Acinetobacter sp. lipA) allowed amplification of these genes in strain Ud-4. To our knowledge, this is the first report on the isolation of a bacterium that can efficiently degrade both edible and mineral oils.     

Isolation and characterization ofAcinetobacter sp. mutants defective in exopolysaccharide biosynthesis

Nitrosoguanidine-induced mutants ofAcinetobacter sp. defective in exopolysaccharide biosynthesis did not differ from the parent strain in distinguishing physiological and biochemical properties, such as requirements for growth factors, utilization of mono- and disaccharides, and resistance to antibiotics. The genetic relation of parent and mutant strains was shown by 16S rRNA PCR analysis. The comparative study of parent and mutant strains with respect to resistance to unfavorable environmental factors confirmed our hypothesis thatAcinetobacter sp. exopolysaccharides perform protective functions. Hybridization experiments revealed the conjugal transfer of plasmid R68.45 fromPseudomonas putida BS228 (R68.45) to mutant but not to the parentAcinetobacter sp. strains. The role of theAcinetobacter sp. exopolysaccharides in providing the genetic stability of this bacterium is discussed.     

Methylovorus mays sp. nov.: A new species of aerobic, obligately methylotrophic bacteria associated with plants

A bacterial strain utilizing methanol as the sole source of carbon and energy was isolated from the maize phyllosphere. Cells are nonpigmented gram-negative motile rods that do not form spores or prosthecae and reproduce by binary fission. The strain does not require vitamins or supplementary growth factors. It is obligately aerobic and urease-, oxidase-, and catalase-positive. The optimum growth temperature is 35–40°C; the optimum pH is 7.0–7.5. The doubling time is 2 h. The bacterium implements the ribulose monophosphate pathway and possesses NAD⁺-dependent 6-phosphogluconate dehydrogenase and enzymes of the glutamate cycle. α-Ketoglutarate dehydrogenase and enzymes of the glyoxylate cycle (isocitrate lyase and malate synthase) are absent. Fatty acids are dominated by palmitic (C_16:0) and palmitoleic (C_16:1) acids. The major phospholipids are phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine. Cardiolipin is present in minor amounts. The dominant ubiquinone is Q₈ The bacterial genome contains genes controlling the synthesis and secretion of cytokinins. The G+C content of DNA is 57.2 mol %, as determined from the DNA thermal denaturation temperature T_m. The bacterium shows low DNA homology (<10%) with restricted facultative methylotrophic bacteria of the genusMethylophilus (M. methylotrophus NCIMB 10515^T andM. leisingerii VKM B-2013¹) and with the obligate methylotrophic bacterium (Methylobacillus glycogenes ATCC 29475^T). DNA homology with the type representative of the genusMethylovorus, M. glucosetrophus VKM B-1745^T, is high (58%). The new isolate was classified as a new species,Methylovorus mays sp. nov.     

Selection and characterization of mannanase-producing bacteria useful for the formation of prebiotic manno-oligosaccharides from copra meal

In order to select bacterial strains effectively secreting mannanase activity for the production of prebiotic mannooligosaccharides, a two-step screening procedure was performed. Enriched cultures from isolation medium containing copra meal were primary screened on an isolation agar medium containing 1% locust bean gum (LBG), which resulted in 48 mannanase-producing bacterial isolates with significant clearing zones on the mannan-containing agar. However, only nine isolates showed appreciable mannanase activities against copra meal in their culture supernatants (0.054–0.185 U/mg of protein) as determined in a standard assay based on the detection of reducing sugars released from this substrate. The isolates CW2-3 and ST1-1 displayed the highest activity against LBG and copra meal, respectively. Copra mannan hydrolysates that were obtained by using crude mannanase from these nine isolates were further used for a secondary screening towards a growth-enhancing activity on Lactobacillus reuteri and inhibitory activity against Escherichia coli as well as Salmonella Enteritidis, resulting in 0.09–2.15 log CFU/ml enhancing activity and low inhibitory activity of 0.46–1.78 log CFU/ml as well as 0.37–1.72 log CFU/ml, respectively. The hydrolysate of CW2-3 mannanase showed the highest enhancing activity of 2.15 log CFU/ml while isolate ST1-1 was most effective with respect to growth inhibition against E. coli E010 and S. Enteritidis S003 with 0.76 and 1.61 log CFU/ml, respectively. Based on morphological, physical, biochemical and genetics properties, isolates CW2-3 and ST1-1 were identified as Klebsiella oxytoca and Acinetobacter sp., respectively. Crude mannanase activity from these two strains was characterized preliminarily. The pH optima of mannanase activity from Klebsiella oxytoca CW2-3 and Acinetobacter sp. ST1-1 were 7 and 6, respectively. The enzymes were stable at 4°C over a pH range of 3–6 and 3–10, respectively.     

Physiological properties and substrate specificity of a pentachlorophenol-degradingPseudomonas species

A bacterial strain capable of utilizing pentachlorophenol (PCP) as sole source of carbon and energy for growth was isolated from enrichment cultures containing 100 mg/l PCP in a mineral salts medium inoculated with contaminated soil from a lumber treatment waste site. The isolate, designated strain SR3, was identified as a species ofPseudomonas by virtue of its physiological and biochemical characteristics. Mineralization of PCP byPseudomonas sp. strain SR3 was demonstrated by loss of detectable PCP from growth medium, stoichiometry of chloride release (5 equivalents of chloride per mole of PCP), and formation of biomass consistent with the concentration of PCP mineralized. PCP-induced cells of strain SR3 showed elevated rates of oxygen consumption in the presence of PCP, and with different chlorinated phenols, with complete degradation of 2,3,5,6-, 2,3,6-, 2,4,6-, 2,4-, and 2,6-chloro-substituted phenols. Concentrations of PCP up to 175 mg/liter supported growth of this organism, but maximal rates of PCP removal were observed at a PCP concentration of 100 mg/liter. Based on its degradative properties,Pseudomonas sp. strain SR3 appears to have utility in bioremediation of soil and water contaminated with PCP.Abbreviations DCP dichlorophenol - TCP trichlorophenol - TeCP tetrachlorophenol Contribution No. 750 from the United States Environmental Protection Agency Environmental Research Laboratory, Gulf Breeze, FL32561, USA. A preliminary report of this work has appeared in abstract form (Resnick & Chapman 1990; Abstr. Annu Meet Amer Soc Microbiol Q-70, p. 300).     

Isolation and characterization of novel Serratia marcescens (AY927692) for pentachlorophenol degradation from pulp and paper mill waste

Seven aerobic bacterial strains were isolated from pulp paper mill waste and screened for pentachlorophenol (PCP) tolerance on PCP containing mineral salt agar medium (MSM). The organism was characterized by 16S rDNA sequencing which showed 99.7% sequence similarity with Serratia marcescens. PCP degradation was routinely monitored with spectrophotometric analysis and further confirmed by HPLC analysis. Among seven strains, ITRC S₇ was found to degrade up to 90.33% of 1.127 mM (300 mg/l) of PCP and simultaneous release of chloride ion (2.435 mM) emphasized the bacterial dechlorination in the medium in presence of glucose as an additional carbon and energy source under optimized condition within 168 h incubation. In absence of glucose bacterium was unable to utilize PCP indicating the phenomenon of co-metabolism. Bacterium was identified as S. marcescens (AY927692), was a novel and potential aerobic bacterial strain capable of degrading PCP in axenic condition. Further, this strain may be used for bioremediation of PCP containing pulp paper mill waste in the environment.     

Influence of environmental parameters on polyphosphate accumulation inAcinetobacter sp.

The regulation of and the optimum conditions for polyphosphate accumulation inAcinetobacter sp. were determined.Acinetobacter strain 210A accumulated polyphosphate in the presence of an intra- or extracellular energy source. The accumulation of polyphosphate during endogenous respiration was stimulated by streptomycin and inhibited by KCN. The highest amount of polyphosphate was found in cells in which energy supply was not limited, namely at low growth rates under sulphur limitation, and in the stationary phase of growth when either the nitrogen or the sulphur source was depleted. The phosphorus accumulation was not affected by the pH between 6.5 and 9. There was a pronounced effect of the temperature on phosphorus accumulation but is varied from strain to strain.Acinetobacter strain 210A accumulated more phosphate at low temperatures, strain B8 showed an optimum accumulation at 27.5° C, while strain P accumulated phosphorus independently of the temperature. The optimum temperature for growth ofAcinetobacter strains tested ranged from 25 to 33° C, and the optimum pH was between 6 and 9.     

Biodegradation of pyrazosulfuron-ethyl by <Emphasis Type="Italic">Acinetobacter</Emphasis> sp. CW17

The pyrazosulfuron-ethyl-degrading bacterium, designated as CW17, was isolated from contaminated soil near the warehouse of the factory producing pyrazosulfuron-ethyl in Changsha city, China. The strain CW17 was identified as Acinetobacter sp. based on analyses of 94 carbon source utilization or chemical sensitivity in Biolog microplates, conventional phenotypic characteristics, and 16S rRNA gene sequencing. When pyrazosulfuron-ethyl was provided as the sole carbon source, the effects of pyrazosulfuron-ethyl concentration, pH, and temperature on biodegradation were examined. The degradation rates of pyrazosulfuron-ethyl at initial concentrations of 5.0, 20.0, and 50.0 mg/L were 48.0%, 77.0%, and 32.6%, respectively, after inoculation for 7 days. The growth of the strain was inhibited at low pH buffers. The chemical degradation occurs much faster at low pH than at neutral and basic pH conditions. The degradation rate of pyrazosulfuron-ethyl at 30°C was faster than those at 20 and 37°C by CW17 strains. Two metabolites of degradation were analyzed by liquid chromatography–mass spectroscopy (LC/MS). Based on the identified products, strain CW17 seemed to be able to degrade pyrazosulfuron-ethyl by cleavage of the sulfonylurea bridge.     

Enrichment, isolation, and characterization of 4-chlorophenol-degrading bacterium Rhizobium sp. 4-CP-20

The objectives of this research were to monitor the variations of species in mixed cultures during the enrichment period, isolate species and identify and characterize the pure 4-chlorophenol (4-CP) degrading strains from enriched mixed cultures. Strain Rhizobium sp. 4-CP-20 was isolated from the acclimated mixed culture. The DGGE result indicated that strain Rhizobium sp. 4-CP-20 was undetectable at the beginning but detectable after 2 weeks of enrichment. The optimum growth temperatures for Rhizobium sp. 4-CP-20 were both 36°C using 350 mg l⁻¹ glucose or sodium acetate as the substrate. The optimum pH range for degrading 100 mg l⁻¹ 4-CP was between 6.89 and 8.20. Strain Rhizobium sp. 4-CP-20 could degrade 4-CP completely within 3.95 days, as the initial 4-CP concentration was 100 mg l⁻¹. If the initial 4-CP concentration was higher than 240 mg l⁻¹, the growth of bacterial cells and the activity of degrading 4-CP were both inhibited.     

Studies revealing bioremediation potential of the strain Burkholderia sp. GB-01 for abamectin contaminated soils

Burkholderia sp. GB-01 strain was used to study different factors affecting its growth for inoculum production and then evaluated for abamectin degradation in soil for optimization under various conditions. The efficiency of abamectin degradation in soil by strain GB-01 was seen to be dependent on soil pH, temperature, initial abamectin concentration, and inoculum size along with inoculation frequency. Induction studies showed that abamectin depletion was faster when degrading cells were induced by pre-exposure to abamectin. Experiments performed with varying concentrations (2–160 mg Kg⁻¹) of abamectin-spiked soils showed that strain GB-01 could effectively degrade abamectin over the range of 2–40 mg Kg⁻¹. The doses used were higher than the recommended dose for an agricultural application of abamectin, taking in account the over-use or spill situations. A cell density of approximately 10⁸ viable cells g⁻¹ dry weight of soil was found to be suitable for bioremediation over a temperature range of 30–35°C and soil pH 7.5–8.5. This is the first report on bacterial degradation of abamectin in soil by a Burkholderia species, and our results indicated that this bacterium may be useful for efficient removal of abamectin from contaminated soils.     

Extracellular β-agarase LSL-1 producing neoagarobiose from a newly isolated agar-liquefying soil bacterium, Acinetobacter sp., AG LSL-1

Summary An agar-liquefying Acinetobacter species capable of utilizing agar as sole source of carbon and energy was isolated from soil samples and the culture conditions were standardized for the maximal production of extracellular agarase. The bacterium was capable of liquefying an agar-plate within 3 days of incubation and produced extracellular agarase within a short period of time (16–18 h) when grown in defined mineral salts medium. Bacterium grew in the pH range 4.0–9.0, optimal at pH 7.0; temperature 25–40 °C and optimal at 37 °C. The agarase secreted by the Acinetobacter strain was inducible by agar and not repressed by other simple sugars when supplemented along with agar in the medium. The bacterium did not require NaCl for growth or production of agarase. The bacterium did not utilize other polysaccharides like κ-carrageenan, alginate, cellulose, and CMC. The activity staining of partially purified agarase preparations after native-PAGE and SDS PAGE revealed the presence of a single zone of clearance corresponding to the molecular weight 100 kDa, suggesting that it is a monomer. Neoagarobiose was the end product of agarose hydrolysis by this enzyme. The agarase was an endo-type glycosidase and belongs to Group-III β-agarase family.     

Oily sludge degradation by bacteria from Ankleshwar, India

Three bacterial strains, Bacillus sp. SV9, Acinetobacter sp. SV4 and Pseudomonas sp., SV17 from contaminated soil in Ankleshwar, India were tested for their ability to degrade the complex mixture of petroleum hydrocarbons (such as alkanes, aromatics, resins and asphaltenes), sediments, heavy metals and water known as oily sludge. Gravimetric analysis showed that Bacillus sp. SV9 degraded approx. 59% of the oily sludge in 5 days at 30 °C whereas Acinetobacter sp. SV4 and Pseudomonas sp. SV17 degraded 37% and 35%. Capillary gas chromatographic analysis revealed that after 5 days the Bacillus strain was able to degrade oily sludge components of chain length C₁₂–C₃₀ and aromatics more effectively than the other two strains. Maximum drop in surface tension (from 70 to 28.4 mN/m) was accompanied by maximum biosurfactant production (6.7 g l⁻¹) in Bacillus sp. SV9 after 72 h, these results collectively indicating that this bacterial strain has considerable potential for bioremediation of oily sludge.     

Influence of salts and pH on growth and activity of a novel facultatively alkaliphilic,extremely salt-tolerant,obligately chemolithoautotrophic sufur-oxidizing Gammaproteobacterium <Emphasis Type="Italic">Thioalkalibacter halophilus</Emphasis> gen. nov., sp. nov. from South-Western Siberian soda lakes

A chemolithoautotrophic sulfur-oxidizing bacterium (SOB) strain ALCO 1 capable of growing at both near-neutral and extremely alkaline pH was isolated from hypersaline soda lakes in S-W Siberia (Altai, Russia). Strain ALCO 1 represents a novel separate branch within the halothiobacilli in the Gammaproteobacteria, which, so far, contained only neutro-halophilic SOB. On the basis of its unique phenotypic properties and distant phylogeny, strain ALCO 1 is proposed as a new genus and species Thioalkalibacter halophilus gen. nov. sp. nov. ALCO 1 was able to grow within a broad range of salinity (0.5–3.5 M of total sodium) with an optimum at around 1 M Na⁺, and pH (7.2–10.2, pH_opt at around 8.5). Na⁺ was required for sulfur-dependent respiration in ALCO 1. The neutral (NaCl)-grown chemostat culture had a much lower maximum growth rate (μ_max), respiratory activity and total cytochrome c content than its alkaline-grown counterpart. The specific concentration of osmolytes (ectoine and glycine-betaine) produced at neutral pH and 3 M NaCl was roughly two times higher than at pH 10 in soda. Altogether, strain ALCO 1 represents an interesting chemolithoautotrophic model organism for comparative investigations of bacterial adaptations to high salinity and pH. Nucleotide sequence accession number: The GenBank/EMBL accession number of the 16S rRNA gene sequence of strain ALCO1^T is EU124668.     

Microbial degradation of cyanide and thiocyanate

The role played by a bacterial community composed ofPseudomonas putida, strain 21;Pseudomonas stutzeri, strain 18; andPseudomonas sp., strain 5, and by physical and chemical factors in the degradation of CN⁻ and SCN⁻ was studied. It was shown that the degradation of CN⁻ is determined both by the action of bacteria and by abiotic physical and chemical factors (pH, O₂, temperature, the medium agitation rate, etc.). The contribution of chemical degradation was found to increase drastically at pH below 9.0; when air was blown through the medium (irrespective of the pH value); under active agitation of the medium; and when the medium surface interfacing air was increased. Even at elevated pH values (9.0-9.2), suboptimal for bacterial growth, the microbial degradation could account for at most 20–25 mg/1 of CN⁻, regardless of its initial concentration. When CN⁻ and SCN⁻ were concurrently present in the medium, the former compound was the first to be degraded by microorganisms. The rate of bacterial degradation of SCN⁻ under continuous cultivation in a chain of reactors was found to depend on its concentration, the medium flow rate, agitation rate, and the pattern of carbon source supply and could exceed 1 g/(l day). CN⁻ and SCN⁻ are utilized by bacteria solely as nitrogen sources. The mechanism of CN⁻ and SCN⁻ degradation by the microbial community is discussed. Deceased.     

Effectiveness of the cleaning performance of the bacterial strain <Emphasis Type="Italic">Acinetobacter</Emphasis> sp. SG06-02 in the petroleum hydrocarbon-polluted intestine of clams

Summary A petroleum-degrading bacterial strain Acinetobacter sp. SG06-02 in the oil-polluted intestine of shellfish clam was previously isolated in our laboratory. In this study, the effectiveness of using its cleaning performance on petroleum pollution was investigated. The accumulation of petroleum in the intestine of Ruditapes philippinarum was determined by a UV spectrophotometer. The survival and growth of the SG06-02 strain in the intestine of Ruditapes philippinarum after oil pollution were examined. The concentration of oil accumulated in the Ruditapes philippinarum intestine quickly rises to 254.97 mg/kg within 12 h after placing the clam in the petroleum-polluted seawater tank. After decontaminating using Acinetaobacter we found that the concentration of petroleum inside the Ruditapes philippinarum declined significantly. The results of the cleaning experiments showed that the degradation activity by using bioremediation method of the strain SG06-02 increased 12.8∼30.2% compared to using clean seawater in 4 days. This research indicated that the petroleum degrading bacteria could survive and was effective in cleaning oily pollutants in the seashell.     

Biodegradation of Swainsonine by Acinetobacter calcoaceticus strain YLZZ-1 and its isolation and identification

Eight swainsonine (SW)-degrading bacteria were isolated from the soil where locoweed was buried for 6 months and one of the strains (YLZZ-1) was selected for further study. Based on morphology, physiologic tests, 16S rRNA gene sequence, and phylogenetic characteristics, the strain showed the greatest similarity to members of the order Acinetobacters and within the order to members of the Acinetobacter calcoaceticus group. The ability of the strain for degrading SW, as sole carbon source, was investigated under different culture conditions. The preferential temperature and initial pH for the strain were 25–35°C and 6–9, respectively. The optimal temperature for the strain was 30°C and the optimal pH was 7.0. There was a positive correlation between degradation rate and inoculation amount. The concentration of SW affected the degradation ability. When the concentration of SW was lower than 100 mg/l, SW decreased immediately after incubation, and when the concentration of SW was 200 mg/l, there was an inhibiting effect for bacteria growth and SW degradation. The strain could degrade SW completely within 14 h when the concentration of SW was 50 mg/l. These results highlight the potential of this bacterium to be used in detoxifying of SW in livestock consuming locoweed.     

Optimization of culture conditions for the production of halothermophilic protease from halophilic bacterium <Emphasis Type="Italic">Chromohalobacter</Emphasis> sp. TVSP101

An extremely halophilic Chromohalobacter sp. TVSP101 was isolated from solar salterns and screened for the production of extracellular halothermophilic protease. Identification of the bacterium was done based upon biochemical tests and the 16S rRNA sequence. The partially purified enzyme displayed maximum activity at pH 8 and required 4.5 M of NaCl for optimum proteolytic activity. In addition, this enzyme was thermophilic and active in broad range of temperature 60–80°C with 80°C as optimum. The Chromohalobacter sp. required 4 M NaCl for its optimum growth and protease secretion and no growth was observed below 1 M of NaCl. The initial pH of the medium for growth and enzyme production was in the range 7.0–8.0 with optimum at pH 7.2. Various cations at 1 mM concentration in the growth medium had no significant effect in enhancing the growth and enzyme production but 0.5 M MgCl₂ concentration enhanced enzyme production. Casein or skim milk powder 1% (w/v) along with 1% peptone proved to be the best nitrogen sources for maximum biomass and enzyme production. The carbon sources glucose and glycerol repressed the protease secretion. Immobilization of whole cells in absence of NaCl proved to be useful for continuous production of halophilic protease.     

Degradation of environmental endocrine disruptor di-2-ethylhexyl phthalate by a newly discovered bacterium, Microbacterium sp. strain CQ0110Y

In this study di-2-ethylhexyl phthalate (DEHP)-degradation strain CQ0110Y was isolated from activated sludge. According to the biophysical/biochemical characteristics and analysis of 16S rDNA, the strain was identified as Microbacterium sp. The results of this study showed the optimal pH value and optimal temperature which influenced the degradation rate in wastewater: pH 6.5–7.5, 25–35°C. Kinetics of degradation reaction had been performed at different initial concentrations and different time. Analyzed with SPSS10.0 software, the DEHP degradation can be described as the same exponential model when the initial DEHP concentration was lower than 1,350 mg/l. The kinetics equation was ln C = −0.4087t + A, with the degradation half life of DEHP in wastewater (1.59 days). To the best of our knowledge, this is the first reported case of DEHP degradation by Microbacterium sp. strain. Xiang Li and Ji-an Chen contributed equally to this work.