title: Nutritional requirements of mycelial growth of Cordyceps sinensis in submerged culture.
abstract: OBJECTIVE
  The nutritional requirements for mycelial growth of Cordyceps sinensis in semi-synthetic liquid media were investigated. The results provide a basis for further physiological study and industrial fermentation of the fungus.
  
  
  RESULTS
  Nutritional requirements, including 17 carbohydrates, 16 nitrogen compounds, nine vitamins, four macro-elements, four trace-elements and eight ratios of carbon to nitrogen, were studied for their effects on the mycelial growth in submerged cultures of C. sinensis by using one-factor-at-a-time and orthogonal matrix methods. Among these variables, sucrose, peptone, folic acid, calcium, zinc and a carbon to nitrogen ratio 12 : 1 were identified as the requirements for the optimum mycelial growth. The concentrations of sucrose, peptone and yeast extract were optimized and the effects of medium composition on mycelial growth were found to be in the order sucrose > yeast extract > peptone. The optimal concentration for mycelial growth was determined as 50 g l(-1) sucrose, 10 g l(-1) peptone and 3 g l(-1) yeast extract.
  
  
  CONCLUSIONS
  Under optimal culture conditions, over 22 g l(-1) of mycelial biomass could be obtained after 40 days in submerged cultures.
  
  
  CONCLUSIONS
  Cordyceps sinensis, one of the most valued medicinal fungi, is shown to grow in axenic culture. This is the first report on nutritional requirements and design of a simplified semi-synthetic medium for mycelial growth of this psychrophilic species, which grows slowly below 20 degrees C. The results of this study will facilitate research on mass production of the fungus under defined culture conditions.
authors.affiliation: Systematic Mycology and Lichenology Laboratory, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: C-H
authors.initials: CH
authors.lastname: Dong
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Yao
mesh_terms: D002241:Carbohydrates / Q000502:physiology; D002244:Carbon / Q000502:physiology; D032661:Cordyceps / Q000254:growth & development*; D003470:Culture Media; D004602:Elements; D025282:Mycelium / Q000254:growth & development*; D009584:Nitrogen / Q000502:physiology; D017672:Nitrogen Compounds / Q000378:metabolism; D009747:Nutritional Physiological Phenomena / Q000502:physiology*; D010461:Peptones / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014815:Vitamins / Q000502:physiology; D015003:Yeasts / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D003470:Culture Media; D004602:Elements; D017672:Nitrogen Compounds; D010461:Peptones; D014815:Vitamins; D013395:Sucrose; D002244:Carbon; D009584:Nitrogen