Biochemical and molecular characterization of poly(aspartic acid) hydrolase-2 from sphingomonas sp. KT-1

Poly(aspartic acid) (PAA) hydrolase-2 was purified from crude soluble cellular extracts of Sphingomonas sp. KT-1 (JCM10459) and characterized to elucidate the mechanism of alpha,beta-poly(d,l-aspartic acid) (tPAA) biodegradation. The molecular mass of PAA hydrolase-2 was 42 kDa, and the isoelectric point was 9.6. The optimum values of pH and temperature for the hydrolysis of alpha-di(l-aspartic acid) by PAA hydrolase-2 were 7.0 and 55 degrees C, respectively. The effect of inhibitors on the hydrolysis of alpha-di(l-aspartic acid) showed that the activity of PAA hydrolase-2 was significantly inhibited by EDTA. Thermally synthesized tPAA was hydrolyzed in the presence of two enzymes, PAA hydrolase-1 and PAA hydrolase-2, to generate aspartic acid. The PAA hydrolase-2 was capable of hydrolyzing alpha-poly(l-aspartic acid) of high molecular weights but had limited activity for tPAA. These results lead us to propose the following mechanism. First, PAA hydrolase-1 hydrolyzes tPAA to yield oligo(aspartic acid) via an endo-mode cleavage, and subsequently, PAA hydrolase-2 hydrolyzes the resultant oligo(aspartic acid) to yield aspartic acid. Analysis of hydrolyzed products from alpha- and beta-penta(l-aspartic acid) revealed that PAA hydrolase-2 catalyzed the exo-mode hydrolysis of alpha- and beta-penta (l-aspartic acid). The gene encoding PAA hydrolase-2 from Sphingomonas sp. KT-1 was cloned, and genetic analysis showed that the deduced amino acid sequence of PAA hydrolase-2 is similar to a putative peptidase, which belongs to the M20/M25/M40 family of proteins, from Caulobacter crescentus CB15.     

Poly(aspartate) hydrolases: biochemical properties and applications

Thermally synthesized poly(aspartate) (tPAA) shows potential for use in a wide variety of products and applications as a biodegradable replacement for non-biodegradable polycarboxylates, such as poly(acrylate). The tPAA molecule has unnatural structures, and the relationship between its biodegradability and structures has been investigated. Two tPAA-degrading bacteria, Sphingomonas sp. KT-1 and Pedobacter sp. KP-2, were isolated from river water; from them, two PAA-hydrolyzing enzymes, PAA hydrolases-1 and -2, were purified and biologically and genetically characterized. Interestingly, not only are PAA hydrolases-1 from those two strains novel in terms of structural genes and substrate specificities (they specifically cleave the amide bond between β-aspartate units in tPAA), they also probably play a central role in tPAA biodegradation by both strains. In green polymer chemistry, one active area of research is the use of purified enzymes for the enzyme-catalyzed synthesis of polypeptides by taking advantage of their substrate specificities. Recently, β-peptides have attracted academic and industrial interest as functional materials as they possess both functions of α-peptides and excellent metabolic stability. As one of the attractive applications of PAA hydrolases, we report here the enzyme-catalyzed synthesis of poly(α-ethyl β-aspartate), which is composed of only β-linkages and belongs to β-peptides, using the unique substrate specificity of the enzyme from Pedobacter sp. KP-2.     

Isolation and characterization of Sphingomonas sp. GTIN11 capable of carbazole metabolism in petroleum

A bacterial culture was isolated from a manufactured gas plant (MGP) soil based on its ability to metabolize the nitrogen-containing heterocycle carbazole. The culture was identified as a Sphingomonas sp. and was given the designation GTIN11. A cloned 4.2kb DNA fragment was confirmed to contain genes responsible for carbazole degradation. DNA sequence analysis revealed that the fragment contained five open reading frames (ORFs) with the deduced amino acid sequence showing homology to; carbazole terminal dioxygenase (ORF1), 2,3-dihydroxybiphenyl dioxygenase subunits (ORF2 and ORF3), meta-cleavage compound hydrolases (ORF4), and ferrodoxin component of bacterial multicomponent dioxygenases (ORF5). The percent similarity was 61% of these proteins or less to known proteins. The specific activity of Sphingomonas sp. GTIN11 for the degradation of carbazole at 37 degrees C was determined to be 8.0 micromol carbazole degraded/min/g dry cell. This strain is unique in expressing the carbazole degradation trait constitutively. Resting cells of Sphingomonas sp. GTIN11 removed 95% of carbazole and 50% of C1-carbazoles from petroleum in a 16-h treatment time.     

Isolation and characterization of dibenzofuran-degrading bacteria

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

Diversity of carbazole-degrading bacteria having the car gene cluster: isolation of a novel gram-positive carbazole-degrading bacterium

Twenty-seven carbazole-utilizing bacterial strains were isolated from environmental samples, and were classified into 14 groups by amplified ribosomal DNA restriction analysis. Southern hybridization analyses showed that 3 and 17 isolates possessed the car gene homologs of Pseudomonas resinovorans CA10 and Sphingomonas sp. strain KA1, respectively. Of the 17 isolates, 2 isolates also have the homolog of the carAa gene of Sphingomonas sp. strain CB3. While the genome of one isolate, a Gram-positive Nocardioides sp. strain IC177, showed no hybridization to any car gene probes, PCR and sequence analyses indicated that strain IC177 had tandemly linked carAa and carC gene homologs whose deduced amino acid sequences showed 51% and 36% identities with those of strain KA1.     

Cloning and sequencing of the endo-cellulase cDNA from Robillarda sp. Y-20

An endo-cellulase cDNA has been screened from a Robillarda sp. Y-20 cDNA expression library using polyclonal antibodies (immunoscreening). Western blot analysis showed that recombinant CMCase I fused to beta-galactosidase with the molecular weight of approximately 150,000 was expressed in Escherichia coli Y1090. Sequence analysis of the cloned cDNA revealed that it consisted of 1,136 nucleotides. By comparison of the amino acid sequence deduced from the cDNA and the N-terminal amino acid sequence of the purified protein (residues 1 to 18, determined by protein sequencing), the cDNA was found to lack 44 nucleotides at its 5' end corresponding to residues 1 to 15. Therefore, the mature cellulase (CMCase I) was deduced to be composed of 375 amino acid residues and the molecular weight of its protein was calculated to be 41,004. Yaguchi et al. reported that the N-terminal amino acid sequence of an endo-beta-1,4-glucanase (endo-cellulase) from Schizophyllum commune was homologous with the active site of various hen egg-white type lysozymes, and the homology offered evidence for a lysozyme-type mechanism in enzymatic hydrolysis of cellulase [Biochem. Biophys. Res. Commun. (1983) 116, 408-411]. Pentill? et al. also pointed out that some amino acid homology was found between endo-glucanase I from Trichoderma reesei and the lysozyme of the phage T4 [Gene (1986) 45, 253-263]. From the result of sequence alignment of the endo-cellulase from Robillarda sp. Y-20 and four kinds of lysozymes, there was a possibility that the endo-cellulase from Robillarda sp. Y-20 also hydrolyzes carboxymethyl cellulose by a lysozyme-type mechanism.     

A second [2Fe-2S] ferredoxin from Sphingomonas sp. Strain RW1 can function as an electron donor for the dioxin dioxygenase

The first step in the degradation of dibenzofuran and dibenzo-p-dioxin by Sphingomonas sp. strain RW1 is carried out by dioxin dioxygenase (DxnA1A2), a ring-dihydroxylating enzyme. An open reading frame (fdx3) that could potentially specify a new ferredoxin has been identified downstream of dxnA1A2, a two-cistron gene (J. Armengaud, B. Happe, and K. N. Timmis, J. Bacteriol. 180:3954-3966, 1998). In the present study, we report a biochemical analysis of Fdx3 produced in Escherichia coli. This third ferredoxin thus far identified in Sphingomonas sp. strain RW1 contained a putidaredoxin-type [2Fe-2S] cluster which was characterized by UV-visible absorption spectrophotometry and electron paramagnetic resonance spectroscopy. The midpoint redox potential of this ferredoxin (E'(0) = -247 +/- 10 mV versus normal hydrogen electrode at pH 8.0) is similar to that exhibited by Fdx1 (-245 mV), a homologous ferredoxin previously characterized in Sphingomonas sp. strain RW1. In in vitro assays, Fdx3 can be reduced by RedA2 (a reductase similar to class I cytochrome P-450 reductases), previously isolated from Sphingomonas sp. strain RW1. RedA2 exhibits a K(m) value of 3.2 +/- 0.3 microM for Fdx3. In vivo coexpression of fdx3 and redA2 with dxnA1A2 confirmed that Fdx3 can serve as an electron donor for the dioxin dioxygenase.     

Growth in coculture stimulates metabolism of the phenylurea herbicide isoproturon by Sphingomonas sp. strain SRS2

Metabolism of the phenylurea herbicide isoproturon by Sphingomonas sp. strain SRS2 was significantly enhanced when the strain was grown in coculture with a soil bacterium (designated strain SRS1). Both members of this consortium were isolated from a highly enriched isoproturon-degrading culture derived from an agricultural soil previously treated regularly with the herbicide. Based on analysis of the 16S rRNA gene, strain SRS1 was assigned to the beta-subdivision of the proteobacteria and probably represents a new genus. Strain SRS1 was unable to degrade either isoproturon or its known metabolites 3-(4-isopropylphenyl)-1-methylurea, 3-(4-isopropylphenyl)-urea, or 4-isopropyl-aniline. Pure culture studies indicate that Sphingomonas sp. SRS2 is auxotrophic and requires components supplied by association with other soil bacteria. A specific mixture of amino acids appeared to meet these requirements, and it was shown that methionine was essential for Sphingomonas sp. SRS2. This suggests that strain SRS1 supplies amino acids to Sphingomonas sp. SRS2, thereby leading to rapid metabolism of (14)C-labeled isoproturon to (14)CO(2) and corresponding growth of strain SRS2. Proliferation of strain SRS1 suggests that isoproturon metabolism by Sphingomonas sp. SRS2 provides unknown metabolites or cell debris that supports growth of strain SRS1. The role of strain SRS1 in the consortium was not ubiquitous among soil bacteria; however, the indigenous soil microflora and some strains from culture collections also stimulate isoproturon metabolism by Sphingomonas sp. strain SRS2 to a similar extent.     

Immobilization of microbial cells on inner epidermis of onion bulb scale for biosensor application

Inner epidermis of onion bulb scales was used as a natural support for immobilization of microbial cells for biosensor application. A bacterium Sphingomonas sp. that hydrolyzes methyl parathion into a chromophoric product, p-nitrophenol (PNP), has been isolated and identified in our laboratory. PNP can be detected by electrochemical and colorimetric methods. Whole cells of Sphingomonas sp. were immobilized on inner epidermis of onion bulb scale by adsorption followed by cross-linking methods. Cells immobilized onion membrane was directly placed in the wells of microplate and associated with the optical transducer. Methyl parathion is an organophosphorus pesticide that has been widely used in the field of agriculture for insect pest control. This pesticide causes environmental pollution and ecological problem. A detection range 4-80 μM of methyl parathion was estimated from the linear range of calibration plot of enzymatic assay. A single membrane was reused for 52 reactions and was found to be stable for 32 days with 90% of its initial hydrolytic activity. The applicability of the cells immobilized onion membrane was also demonstrated with spiked samples.     

好氧条件下Sphingomonassp.XJ1降解DBP途径的研究

在三角瓶中采用Sphingomonas sp.XJ1对邻苯二甲酸丁酯(DBP)进行好氧降解,以考察DBP的降解途径。分别对降解16h、32h和40h的DBP样品进行代谢产物分析,可判定保留时间为4.79min和5.11min所对应的代谢产物分别为原儿茶酸和邻苯二甲酸。由此可知,菌株Sphingomonas sp.XJ1对DBP的降解遵循DBP好氧生物降解途径的一般途径。即在菌株XJ1的作用下,DBP首先水解为MBP,继而水解为PA,经由PCA最终完全降解为CO2和H2O。     

Effect of rhamnolipids on degradation of anthracene by two newly isolated strains, Sphingomonas sp. 12A and Pseudomonas sp. 12B

Anthracene is a PAH that is not readily degraded, plus its degradation mechanism is still not clear. Thus, two strains of bacteria-degrading bacteria were isolated from longterm petroleum-polluted soil and identified as Sphingomonas sp. 12A and Pseudomonas sp. 12B by a 16S rRNA sequence analysis. To further enhance the anthracene-degrading ability of the two strains, the biosurfactants produced by Pseudomonas aeruginosa W3 were used, which were characterized as rhamnolipids. It was found that these rhamnolipids dramatically increased the solubility of anthracene, and a reverse-phase HPLC assay showed that the anthracene degradation percentage after 18 days with Pseudomonas sp. 12B was significantly enhanced from 34% to 52%. Interestingly, their effect on the degradation by Sphingomonas sp. 12A was much less, from 35% to 39%. Further study revealed that Sphingomonas sp. 12A also degraded the rhamnolipids, which may have hampered the effect of the rhamnolipids on the anthracene degradation.     

PCP degradation is mediated by closely related strains of the genus Sphingomonas

There have been numerous reports in the literature of diverse bacteria capable of degrading pentachlorophenol (PCP). In order to gain further insight into the phylogenetic relationships of PCP-degrading bacteria, we examined four strains: Arthrobacter sp. strain ATCC 33790, Flavobacterium sp. strain ATCC 39723, Pseudomonas sp. strain SR3, and Sphingomonas sp. strain RA2. These organisms were isolated from different geographical locations and all of them degrade high concentrations (100–200 mg/L) of PCP. Southern blot analyses determined that these bacteria all harbour DNA that encodes similar, if not identical, genes involved in PCP degradation. Comparison of the 16S rRNA nucleotide sequences revealed that these organisms were very closely related and, in fact, represent a monophyletic group. The 16S rRNA analyses together with fatty acid and sphingolipid analyses strongly suggest that the four strains are members of the genus Sphingomonas . The close relationship of the four organisms is supported by nucleotide sequence analysis data of the pcpB locus encoding PCP-4-monooxygenase, the first enzyme in the PCP degradative pathway.     

Anti-platelet activity of a three-finger toxin (3FTx) from Indian monocled cobra (Naja kaouthia) venom

A low molecular weight anti-platelet peptide (6.9 kDa) has been purified from Naja kaouthia venom and was named KT-6.9. MALDI-TOF/TOF mass spectrometry analysis revealed the homology of KT-6.9 peptide sequence with many three finger toxin family members. KT-6.9 inhibited human platelet aggregation process in a dose dependent manner. It has inhibited ADP, thrombin and arachidonic acid induced platelet aggregation process in dose dependent manner, but did not inhibit collagen and ristocetin induced platelet aggregation. Strong inhibition (70%) of the ADP induced platelet aggregation by KT-6.9 suggests competition with ADP for its receptors on platelet surface. Anti-platelet activity of KT-6.9 was found to be 25 times stronger than that of anti-platelet drug clopidogrel. Binding of KT-6.9 to platelet surface was confirmed by surface plasma resonance analysis using BIAcore X100. Binding was also observed by a modified sandwich ELISA method using anti-KT-6.9 antibodies. KT-6.9 is probably the first 3FTx from Indian monocled cobra venom reported as a platelet aggregation inhibitor.     

一株多环芳烃降解菌的鉴定及GST基因克隆和序列分析

由石油污染土壤中分离到一株能以多环芳烃（菲、芴、萘）为唯一碳源的细菌,经形态观察、生理生化（BiologGN）和 G+C mol%分析,鉴定该菌为少动鞘氨醇单胞菌(Sphingomonas paucimobilis)。与16S rDNA序列同源性的比较进一步确证了鉴定结果。经菲诱导后的细菌谷胱甘肽S转移酶（Glutathione Stransferase, GST）酶活明显高于未诱导前,表明谷胱甘肽S转移酶可能与多环芳烃的降解有关。根据该酶基因的同源性序列设计引物,PCR扩增出编码谷胱甘肽S转移酶基因片段,进一步证实在该菌中有GST的存在。测序后基于编码GST的基因所进行的系统发育分析表明,该多环芳烃降解菌与其它多环芳烃降解菌在进化上亲缘关系较近。     

Chemotaxonomic and phylogenetic analyses of Sphingomonas strains isolated from ears of plants in the family Gramineae and a proposal of Sphingomonas roseoflava sp. nov

Chemotaxonomic and phylogenetic characteristics of Sphingomonas strains isolated from plants of the family Gramineae were investigated. All strains contained the monosaccharide (glucuronic acid) type of glycosphingolipid (GSL-1). Most were found also to contain the oligosaccharide-type glycosphingolipids. Fatty acid and sphingosine profiles of the isolates were identical, although the ratio of the contents varies among the isolates. They all contained ubiquinone Q-10, and the G1C contents were from 66 to 68%. Phylogenetic analysis using 16S rRNA gene base sequences revealed that all the isolates were placed in the phylogenetic group of Sphingomonas paucimobilis in the alpha-4 subclass of Proteobacteria. By DNA-DNA hybridization experiments, the plant isolates were divided into five genotypic groups (groups 1 to 5). The strains of group 5 showed common physiological characteristics and formed pink-yellow colored colonies. Based on these results, Sphingomonas roseoflava sp. nov. was proposed for that homology group.     

好氧条件下Sphingomonas sp．XJ1降解DBP途径的研究

在三角瓶中采用Sphingomonas sp．XJ1对邻苯二甲酸丁酯（DBP）进行好氧降解,以考察DBP的降解途径。分别对降解16h、32h和40h的DBP样品进行代谢产物分析,可判定保留时间为4．79min和5．11min所对应的代谢产物分别为原儿茶酸和邻苯二甲酸。由此可知,菌株Sphingomonassp．XJ1对DBP的降解遵循DBP好氧生物降解途径的一般途径。即在菌株XJI的作用下,DBP首先水解为MBP,继而水解为PA,经由PCA最终完全降解为CO2和H2O。     

Sphingomonas astaxanthinifaciens sp. nov., a novel astaxanthin-producing bacterium of the family Sphingomonadaceae isolated from Misasa, Tottori, Japan

A red-pigmented, Gram-negative, motile, strictly aerobic, mesophilic, oval- or short rod-shaped bacterium (TDMA-17(T)) was isolated from fresh water collected at Misasa, a radioactive site in Japan. TDMA-17(T) was slightly tolerant against gamma-ray irradiation, and effectively produced carotenoids (2.8 mg g(-1) dry cells) including, astaxanthin and astaxanthin isomers. Phylogenetic analysis based on 16S rRNA gene sequences placed TDMA-17(T) in a distinct lineage in the family Sphingomonadaceae, and the highest degree of sequence similarity determined were to Sphingomonas aerolata NW12(T) (94.5%), Sphingomonas aurantiaca MA101b(T) (94.0%), Sphingomonas melonis DAPP-PG 224(T) (94.0%), Sphingomonas asaccharolytica IFO 15499(T) (93.9%) and Sphingomonas abaci C42(T) (93.9%). The major fatty acids were C(17 : 1)omega6c (33.0%) and C(18 : 1)omega7c (20.8%). The DNA G+C content was 67.7 mol%. The presence of Q-10 as the main ubiquinone, the presence of Sphingomonadaceae-specific sphingoglycolipid in the polar lipid profiles, the presence of 2-hydroxy fatty acids and the absence of 3-hydroxy fatty acids supported the identification of this strain as a member of the genus Sphingomonas sensu stricto. Phylogenetic distinctiveness and unique phenotypic characteristics differentiated strain TDMA-17(T) from the closely related Sphingomonas species. The results of polyphasic taxonomic analyses suggested that TDMA-17(T) represents a novel Sphingomonas species, for which the name Sphingomonas astaxanthinifaciens sp. nov. is proposed. The type strain is TDMA-17(T) (=NBRC 102146=CCUG 53608).     

呋喃丹降解菌CDS-1的双标记菌株的构建

用Sau3AI消化呋喃丹降解菌Sphingomonassp.CDS-1的基因组DNA,将所得DNA片段与BamHⅠ酶切的启动子探针载体pRobe-GFP酶连后转化E.coliDH5α感受态细胞,在选择性平板上培养,从大约1×104个菌落中筛选到50个含启动子片段的阳性克隆。挑选其中一个发光强度最强的阳性克隆F7,将它的重组质粒pF7用EcoRⅠ和HindⅢ双酶切后得到包含Sphingomonassp.CDS-1启动子和gfp基因的DNA片段,将该片段克隆到广宿主载体pPZP201上,得到pPZP201-gfp质粒。将pPZP201-gfp通过三亲接合转移至Sphingomonassp.CDS-1中得到GFP标记菌株CDS-gfp,经荧光显微镜观察,gfp基因在CDS-gfp中表达量很高。对标记菌株进行连续传代10次(48h/次),发现pPZP201-gfp依然存在,而且发光明显。通过NotⅠ酶切位点把linA基因连接到pUT/mini-Tn5上构建新的转座子载体pUT/mini-Tn5-linA。以pRK600为辅助质粒将pUT/mini-Tn5-linA引入到CDS-1中,linA基因通过转座作用,插入到CDS-gfp的染色体中,得到双标记菌株CDS-GFP-LinA。该菌株是一株能同时降解γ-六六六和呋喃丹的基因工程菌,本研究的结果为研究Sphingomonassp.CDS-1的生态学行为奠定了基础。     

Sequence and analysis of the 46.6-kb plasmid pA1 from Sphingomonas sp. A1 that corresponds to the typical IncP-1beta plasmid backbone without any accessory gene

Sphingomonas sp. A1 (strain A1) is capable of directly incorporating macromolecules (e.g., alginate) through the specialized import system--"super-channel." Here, we report the complete DNA sequence and genetic organization of plasmid pA1 from strain A1. Nucleotide sequence analysis revealed that pA1 comprises 46,557 bp encoding 49 open reading frames (ORFs) with 65% G+C content and abundant GCCG/CGGC motifs. Many predicted pA1 ORFs showed high similarity to pA81 ORFs; pA81 is supposedly a self-transmissible promiscuous incompatibility (Inc) group P-1beta plasmid. Unlike any reported IncP-1 plasmids, pA1 contains no inserted mobile genetic elements. The genetic organization and predicted pA1 ORFs showed greater similarity to the IncP-1beta plasmid backbone than to the IncP-1alpha plasmid backbone. pA1 contains restriction site-associated repeat sequences typical of the IncP-1beta but absent in the IncP-1alpha and delta subgroups. Thus, the overall pA1 structure corresponds to that of the typical IncP-1beta plasmids. Phylogenetic analysis of the replication-associated proteins suggested that pA1 may have diverged later along with the two IncP-1beta plasmids--pA81 and pB4. The 2.4-kb duplicates of stable inheritance genes klcAB and korC in pA1 possibly resulted from insertion and/or recombination events via the repeat sequences flanking these duplicates.     

Biodegradation of bisphenol A and related compounds by Sphingomonas sp. strain BP-7 isolated from seawater

A bacterium capable of assimilating 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), strain BP-7, was isolated from offshore seawater samples on a medium containing bisphenol A as sole source of carbon and energy, and identified as Sphingomonas sp. strain BP-7. Other strains, Pseudomonas sp. strain BP-14, Pseudomonas sp. strain BP-15, and strain no. 24A, were also isolated from bisphenol A-enrichment culture of the seawater. These strains did not degrade bisphenol A, but accelerated the degradation of bisphenol A by Sphingomonas sp. strain BP-7. A mixed culture of Sphingomonas sp. strain BP-7 and Pseudomonas sp. strain BP-14 showed complete degradation of 100 ppm bisphenol A within 7 d in SSB-YE medium, while Sphingomonas sp. strain BP-7 alone took about 40 d for complete consumption of bisphenol A accompanied by accumulation of 4-hydroxyacetophenone. On a nutritional supplementary medium, Sphingomonas sp. strain BP-7 completely degraded bisphenol A and 4-hydroxyacetophenone within 20 h. The strain degraded a variety of bisphenols, such as 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, and 1,1-bis(4-hydroxyphenyl)cyclohexane, and hydroxy aromatic compounds such as 4-hydroxyacetophenone, 4-hydroxybenzoic acid, catechol, protocatechuic acid, and hydroquinone. The strain did not degrade bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)sulfone, or bis(4-hydroxyphenyl)sulfide.