title: Improvement of (R)-3-hydroxybutyric acid secretion during Halomonas sp. KM-1 cultivation with saccharified Japanese cedar by the addition of urea.
abstract: Japanese cedar (Cryptomeria japonica) is a major species in artificial Japanese forests. The Halomonas sp. KM-1 was recently isolated and found to grow effectively on saccharified Japanese cedar wood, resulting in the intracellular storage of poly-(R)-3-hydroxybutyric acid (PHB) under aerobic conditions. Under microaerobic conditions, the extracellular secretion of (R)-3-hydroxybutyric acid ((R)-3-HB) led to the degradation of intracellular PHB. In this study, the production of PHB and the secretion of (R)-3-HB using saccharified Japanese cedar were much improved in cultures that were grown in the presence of urea. The level of intracellular PHB production after 36 h under aerobic cultivation was 23·6 g l(-1) ; after shifting to microaerobic conditions for 24 h, the (R)-3-HB concentration in the medium reached 21·1 g l(-1) . Thus, KM-1 efficiently utilizes saccharified Japanese cedar to produce PHB and secretes (R)-3-HB, making it a practical candidate for use in the industrial production of (R)-3-HB.
  
  
  CONCLUSIONS
  Japanese cedar is a major species grown in artificial Japanese forests, and its thinning is crucial for the health of artificial forests and the Japanese economy. Halomonas sp. KM-1 grew effectively on saccharified Japanese cedar wood, resulting in intracellular storage of poly-(R)-3-hydroxybutyric acid (PHB) under aerobic conditions. Under microaerobic conditions, extracellular secretion of (R)-3-hydroxybutyric acid ((R)-3-HB) caused intracellular PHB degradation. (R)-3-HB is a chiral compound that is useful in the chemical, health food and pharmaceutical industries. The production of PHB and secretion of (R)-3-HB using saccharified wood was dramatically improved, which may positively affect its future industrial production.
authors.affiliation: Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kawata
authors.affiliation: Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nojiri
authors.affiliation: Energy Technology Laboratories, Osaka Gas Co., Ltd., Konohana-ku, Osaka, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Matsushita
authors.affiliation: Energy Technology Laboratories, Osaka Gas Co., Ltd., Konohana-ku, Osaka, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Tsubota
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000096:biosynthesis / Q000378:metabolism*; D000332:Aerobiosis; D032485:Cryptomeria / Q000382:microbiology*; D005285:Fermentation; D020632:Halomonas / Q000254:growth & development / Q000378:metabolism*; D007218:Industrial Microbiology / Q000379:methods*; D014508:Urea / Q000378:metabolism; D014934:Wood / Q000378:metabolism* / Q000382:microbiology
chemical_list: D014508:Urea; D020155:3-Hydroxybutyric Acid
keywords: (R)-3-hydroxybutyric acid; Halomonas; Japanese cedar (Cryptomeria japonica); Poly-(R)-3-hydroxybutyric acid (PHB); biopolymers; urea