title: Benzoic acid fermentation from starch and cellulose via a plant-like β-oxidation pathway in Streptomyces maritimus.
abstract: BACKGROUND
  Benzoic acid is one of the most useful aromatic compounds. Despite its versatility and simple structure, benzoic acid production using microbes has not been reported previously. Streptomyces are aerobic, Gram-positive, mycelia-forming soil bacteria, and are known to produce various kinds of antibiotics composed of many aromatic residues. S. maritimus possess a complex amino acid modification pathway and can serve as a new platform microbe to produce aromatic building-block compounds. In this study, we carried out benzoate fermentation using S. maritimus. In order to enhance benzoate productivity using cellulose as the carbon source, we constructed endo-glucanase secreting S. maritimus.
  
  
  RESULTS
  After 4 days of cultivation using glucose, cellobiose, or starch as a carbon source, the maximal level of benzoate reached 257, 337, and 460 mg/l, respectively. S. maritimus expressed β-glucosidase and high amylase-retaining activity compared to those of S. lividans and S. coelicolor. In addition, for effective benzoate production from cellulosic materials, we constructed endo-glucanase-secreting S. maritimus. This transformant efficiently degraded the phosphoric acid swollen cellulose (PASC) and then produced 125 mg/l benzoate.
  
  
  CONCLUSIONS
  Wild-type S. maritimus produce benzoate via a plant-like β-oxidation pathway and can assimilate various carbon sources for benzoate production. In order to encourage cellulose degradation and improve benzoate productivity from cellulose, we constructed endo-glucanase-secreting S. maritimus. Using this transformant, we also demonstrated the direct fermentation of benzoate from cellulose. To achieve further benzoate productivity, the L-phenylalanine availability needs to be improved in future.
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Noda
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kitazono
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tanaka
authors.forename: Chiaki
authors.initials: C
authors.lastname: Ogino
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D000681:Amylases / Q000235:genetics / Q000378:metabolism; D019817:Benzoic Acid / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D005285:Fermentation; D010084:Oxidation-Reduction; D013213:Starch / Q000378:metabolism*; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*; D001617:beta-Glucosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D019817:Benzoic Acid; D002482:Cellulose; D013213:Starch; D000681:Amylases; D001617:beta-Glucosidase