Patent ID: 8883452

Claim:
A method of producing substantially pure heparosan from E. coli K5, comprising (a) culturing E. coli K5 in defined medium with glucose as the primary carbon source wherein culturing consists of a batch growth phase and fed batch growth stage, wherein (i) the medium used in the batch growth stage comprises (per liter) about 20 g glucose, 10-300 mg thiamine, about 13.5 g KH 2 PO 4 ; about 4.0 g (NH 4 ) 2 HPO 4 , about 1.4 g MgSO 4 .7H 2 O, about 1.7 g citric acid, and about 10.0 mL trace metal solution; wherein the trace metal solution consists essentially of (per L of 5 M HCl) 10.0 g FeSO 4 .7H 2 O, 2.0 g CaCl 2 , 2.2 g ZnSO 4 .7H 2 O, 0.5 g MnSO 4 .4H 2 O, 1.0 g CuSO 4 .5H 2 O, 0.1 g (NH 4 ) 6 Mo 7 O 24 .4H 2 O, and 0.02 g Na 2 B 4 O 7 .10H 2 O and wherein; (ii) the feeding medium used in the fed batch growth stage consists of (per L): 250-1000 g glucose, 20 g MgSO 4 , 0.15-0.5 g thiamine, and optionally 47 g KH 2 PO 4 , and (iii) wherein oxygen is provided by sparged air with or without supplemental oxygen (b) binding heparosan to a solid phase with subsequent elution; and (c) precipitating heparosan from the eluate; wherein said substantially pure heparosan is at least 90% pure.