title: A novel microbial interaction: obligate commensalism between a new gram-negative thermophile and a thermophilic Bacillus strain.
abstract: Obligately commensal interaction between a new gram-negative thermophile and a thermophilic Bacillus strain was investigated. From compost samples, a mixed culture showing tyrosine phenol-lyase activity was enriched at 60 degrees C. The mixed culture consisted of a thermophilic gram-negative strain, SC-1, and a gram-positive spore-forming strain, SK-1. In mixed cultures, strain SC-1 started to grow only when strain SK-1 entered the stationary phase. Although strain SC-1 showed tyrosine phenol lyase activity, we could not isolate a colony with any nutrient medium. For the isolation and cultivation of strain SC-1, we added culture supernatant and cell extract of the mixed culture to the basal medium. The supernatant and cell extract of the mixed culture contained heat-stable and heat-labile factors, respectively, that are essential to the growth of strain SC-1. During pure cultures of strain SK-1, the heat-stable growth factors were released during the growth phase and the heat-labile growth factors were produced intracellularly at the early stationary phase. Strain SC-1 was gram-negative and microaerophilic, and grows optimally at 60 degrees C. Based on these results, we propose a novel commensal interaction between a new gram-negative thermophile, strain SC-1, and Bacillus sp. strain SK-1.
authors.affiliation: Microbial Conversion RU., Korea Research Institute of Bioscience and Biotechnology, Taejon.
authors.forename: S K
authors.initials: SK
authors.lastname: Rhee
authors.forename: S G
authors.initials: SG
authors.lastname: Lee
authors.forename: S P
authors.initials: SP
authors.lastname: Hong
authors.forename: Y H
authors.initials: YH
authors.lastname: Choi
authors.forename: J H
authors.initials: JH
authors.lastname: Park
authors.forename: C J
authors.initials: CJ
authors.lastname: Kim
authors.forename: M H
authors.initials: MH
authors.lastname: Sung
mesh_terms: D001407:Bacillus / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D018920:Coculture Techniques; D003470:Culture Media; D006090:Gram-Negative Bacteria / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D006358:Hot Temperature; D008854:Microscopy, Electron; D013559:Symbiosis; D014447:Tyrosine Phenol-Lyase / Q000096:biosynthesis
chemical_list: D003470:Culture Media; D014447:Tyrosine Phenol-Lyase