title: Development of a chemically defined medium for the production of enterolysin A from Enterococcus faecalis B9510.
abstract: OBJECTIVE
  This study aimed to develop a simplified chemically defined medium that could sustain the growth and bacteriocin (enterolysin A) production by Enterococcus faecalis B9510.
  
  
  RESULTS
  The nutritional requirements of E. faecalis B9510 in a chemically defined medium were determined by single omission experiments. It was observed that eight amino acids (arginine, glycine, histidine, isoleucine, leucine, methionine, tryptophan and valine), three B vitamins (nicotinic acid, Ca-pantothenic acid and pyridoxal) and magnesium sulphate were essential for growth. Based on this information, a Simplified Defined Medium (SDM) was formed consisting of 26 components. Comparison of SDM with M-17 showed that growth and bacteriocin production in SDM was similar to that in M-17. The bacteriocin from SDM was then purified by ultrafiltration. The retentate of ultrafiltration step was analysed by SDS-PAGE and the results showed a single active band in the gel, which was excised and analysed by mass spectrometry, which indicated that the active band was enterolysin A, a cell wall degrading bacteriocin.
  
  
  CONCLUSIONS
  A simplified defined medium can be formulated for the growth and bacteriocin production by Enterococcus faecalis, whose efficiency is comparable with that of a complex commercial medium.
  
  
  CONCLUSIONS
  The development of such a medium can be useful for bacteriocin production and subsequent purification in a simplified manner and, therefore, helpful in the identification of novel bacteriocins.
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Palmerston North, New Zealand.
authors.forename: H
authors.initials: H
authors.lastname: Khan
authors.forename: S H
authors.initials: SH
authors.lastname: Flint
authors.forename: P-L
authors.initials: PL
authors.lastname: Yu
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001430:Bacteriocins / Q000096:biosynthesis* / Q000302:isolation & purification; D001431:Bacteriological Techniques; D019149:Bioreactors; D003470:Culture Media / Q000737:chemistry*; D013293:Enterococcus faecalis / Q000378:metabolism*; D014803:Vitamin B Complex / Q000737:chemistry
chemical_list: D000596:Amino Acids; D001430:Bacteriocins; D003470:Culture Media; C522987:enterolysin A, Enterococcus faecalis; D014803:Vitamin B Complex