Patent ID: 7919658

Claim:
A process of purifying biologically-produced 1,3-propanediol from the fermentation broth of a microorganism able to produce 1,3-propanediol, comprising the sequential steps of: (a) subjecting the fermentation broth to filtration; (b) subjecting the product of step (a) to two ion exchange purification steps comprising: i) anionic exchange; and ii) cationic exchange wherein ionic impurities are removed; (c) subjecting the product of step (ii) to chemical reduction; and (d) subjecting the product of step (c) to at least two distillation procedures comprising at least two distillation columns wherein one of said distillation columns removes molecules having a boiling point exceeding the boiling point of 1,3-propanediol and the other of said distillation columns removes molecules having a boiling point below the boiling point of 1,3-propanediol whereby purified biologically-produced 1,3-propanediol having a concentration of total organic impurities of less than about 400, an absorbance at 275 nm of less than 0.075 and a L*a*b*, b* color value of less than about 0.15 is produced.