title: Tender coconut water an economical growth medium for the production of recombinant proteins in Escherichia coli.
abstract: BACKGROUND
  Escherichia coli is most widely used prokaryotic expression system for the production of recombinant proteins. Several strategies have been employed for expressing recombinant proteins in E.coli. This includes the development of novel host systems, expression vectors and cost effective media. In this study, we exploit tender coconut water (TCW) as a natural and cheaper growth medium for E.coli and Pichia pastoris.
  
  
  RESULTS
  E.coli and P.pastoris were cultivated in TCW and the growth rate was monitored by measuring optical density at 600 nm (OD(600nm)), where 1.55 for E.coli and 8.7 for P.pastoris was obtained after 12 and 60 hours, respectively. However, variation in growth rate was observed among TCW when collected from different localities (0.15-2.5 at OD(600nm)), which is attributed to the varying chemical profile among samples. In this regard, we attempted the supplementation of TCW with different carbon and nitrogen sources to attain consistency in growth rate. Here, supplementation of TCW with 25 mM ammonium sulphate (TCW-S) was noted efficient for the normalization of inconsistency, which further increased the biomass of E.coli by 2 to 10 folds, and 1.5 to 2 fold in P.pastoris. These results indicate that nitrogen source is the major limiting factor for growth. This was supported by total nitrogen and carbon estimation where, nitrogen varies from 20 to 60 mg/100 ml while carbohydrates showed no considerable variation (2.32 to 3.96 g/100 ml). In this study, we also employed TCW as an expression media for recombinant proteins by demonstrating successful expression of maltose binding protein (MBP), MBP-TEV protease fusion and a photo switchable fluorescent protein (mEos2) using TCW and the expression level was found to be equivalent to Luria Broth (LB).
  
  
  CONCLUSIONS
  This study highlights the possible application of TCW-S as a media for cultivation of a variety of microorganisms and recombinant protein expression.
authors.affiliation: Protein Technology Core, Centre for Cellular and Molecular Platforms, NCBS Campus, GKVK, Bellary Road, Bangalore 560 065, Karnataka, India. munish@ncbs.res.in.
authors.forename: Narendrakumar
authors.initials: N
authors.lastname: Sekar
authors.forename: Soumya Kariyadan
authors.initials: SK
authors.lastname: Veetil
authors.forename: Muniasamy
authors.initials: M
authors.lastname: Neerathilingam
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D018533:Biomass; D002241:Carbohydrates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D003059:Cocos / Q000737:chemistry*; D003470:Culture Media / Q000737:chemistry*; D004926:Escherichia coli / Q000254:growth & development*; D015870:Gene Expression; D009584:Nitrogen / Q000737:chemistry; D010843:Pichia / Q000254:growth & development; D011994:Recombinant Proteins / Q000096:biosynthesis*
chemical_list: D002241:Carbohydrates; D003470:Culture Media; D011994:Recombinant Proteins; D002244:Carbon; D009584:Nitrogen; D000645:Ammonium Sulfate