title: Streptomyces griseus enhances denitrification by Ralstonia pickettii K50, which is possibly mediated by histidine produced during co-culture.
abstract: Ralstonia pickettii K50 (strain K50) is a denitrifying bacterium that produces low levels of N(2)O under aerobic conditions. In this study, we found that co-culturing of strain K50 with Streptomyces griseus significantly enhanced the denitrification activity of strain K50 in an artificial wastewater (AWW) system. Most factors that enhance denitrification activity were in the high molecular weight fraction of the cell-free broth of S. griseus, and were suggested to be extracellular proteases. Further investigation revealed that the cultivation of strain K50 in protease-treated AWW medium fully enhanced denitrification, and that a shortage of amino acids in the medium limited it. Among the 20 standard amino acids tested, only histidine had a significant effect in inducing denitrification by strain K50. Our results indicate that histidine is a novel inducer of bacterial denitrification.
authors.affiliation: Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Takaki
authors.forename: Shinya
authors.initials: S
authors.lastname: Fushinobu
authors.forename: Sang-Wan
authors.initials: SW
authors.lastname: Kim
authors.forename: Morio
authors.initials: M
authors.lastname: Miyahara
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Wakagi
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Shoun
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media; D006639:Histidine / Q000494:pharmacology*; D007700:Kinetics; D017744:Medical Waste Disposal; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D009609:Nitrous Oxide / Q000378:metabolism; D049920:Ralstonia pickettii / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D012722:Sewage; D013305:Streptomyces griseus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003470:Culture Media; D017744:Medical Waste Disposal; D009566:Nitrates; D009573:Nitrites; D012722:Sewage; D006639:Histidine; D009609:Nitrous Oxide