A　17　alpha-ethynylestradiol　(EE2)-degrading　bacterium　was　isolated　from　the　activated　sludge　of　the　wastewater　treatment　plant　(WWTP)　of　an　oral　contraceptives　producing　factory　in　Beijing,　China.　On　the　basis　of　its　morphology,　biochemical　properties　and　the　16S　rDNA　sequence　analysis,　this　strain　was　identified　as　Sphingobacterium　sp.　JCR5.　This　strain　grew　on　EE2　as　sole　source　of　carbon　and　energy,　and　metabolized　up　to　87%　of　the　substrate　added　(30　mg　l(-1))　within　10　d　at　30　degrees　C.　In　addition　to　EE2　the　strain　could　be　cultivated　on　steroidal　estrogens　like　estrone　(E1),　17　beta-estradiol　(E2),　estriol　(E3)　and　mestranol　(MeEE2),　the　intermediates　of　contraceptive　medicine　processing　and　on　some　aromatic　compounds.　Mass　spectrum　analysis　of　the　EE2　degradation　showed　that　in　the　first　step　it　is　oxygenized　to　E1,　2-hydroxy-2,4-dienevaleric　acid　and　2-hydroxy-2,4-diene-1,6-dioic　acid,　which　are　the　main　catabolic　intermediates.　The　former　was　analogous　to　the　pathway　of　a　previously　reported　testosterone-degrading　bacterium　Comamonas　testosteroni　TA441　and　the　latter　is　a　metabolite　with　a　different　cleavage　position　of　3-hydroxy-4,5-9,10-disecoestrane-1(10),2-diene-5,9,17-trione-4-oic　acid　from　the　former.　(c)　2006　Elsevier　Ltd.　All　rights　reserved.