A process of purifying 1,4-butanediol (1,4-BDO) comprising culturing a modified non-naturally occurring organism to produce a 1,4-BDO in a fermentation broth, subjecting the fermentation broth to a separation procedure to obtain a separated 1,4-BDO product, and subjecting the separated 1,4-BDO product to water removal and salt removal to produce the crude 1,4-BDO mixture, wherein the separation procedure consists of a first filtration and a second filtration, wherein the first filtration is microfiltration or ultrafiltration, and wherein the second filtration is nanofiltration; the process further comprising the steps: (a) subjecting a crude 1,4-BDO mixture to a first column distillation procedure to remove materials with a boiling point lower than 1,4-BDO from the crude 1,4-BDO mixture to produce a first 1,4-BDO-containing product stream; and (b) subjecting the first 1,4-BDO-containing product stream to a second column distillation procedure to remove materials with boiling points higher than 1,4-BDO as a first high-boilers stream, to produce a purified 1,4-BDO product, wherein the purified 1,4-BDO product, optionally in a vapor phase, is collected from a side-draw of the second column distillation procedure; and (c) subjecting the first high-boilers stream to wiped-film evaporation (WFE) to produce a first WFE distillate and subjecting the first WFE distillate to step (b); or (d) subjecting the first 1,4-BDO-containing product stream, prior to performing step (b), to an intermediate column distillation procedure to remove materials with boiling points higher than 1,4-BDO as a second high-boilers stream, further comprising (c) subjecting the second high-boilers stream to wiped-film evaporation (WFE) producing a second WFE distillate and subjecting the second WFE distillate to step (d) and optionally further comprising (e) treating the first 1,4-BDO-containing product stream with a hydrogenation reaction prior to performing step (b); wherein optionally the process further comprises subjecting the crude 1,4-BDO mixture to a polishing ion exchange using a polishing ion exchange resin that is an anion exchange resin, and wherein optionally the water removal is by evaporation or the salt removal is by primary ion exchange. (a) subjecting a crude 1,4-BDO mixture to a first column distillation procedure to remove materials with a boiling point lower than 1,4-BDO from the crude 1,4-BDO mixture to produce a first 1,4-BDO-containing product stream; and (b) subjecting the first 1,4-BDO-containing product stream to a second column distillation procedure to remove materials with boiling points higher than 1,4-BDO as a first high-boilers stream, to produce a purified 1,4-BDO product, wherein the purified 1,4-BDO product, optionally in a vapor phase, is collected from a side-draw of the second column distillation procedure; and (c) subjecting the first high-boilers stream to wiped-film evaporation (WFE) to produce a first WFE distillate and subjecting the first WFE distillate to step (b); or (d) subjecting the first 1,4-BDO-containing product stream, prior to performing step (b), to an intermediate column distillation procedure to remove materials with boiling points higher than 1,4-BDO as a second high-boilers stream, further comprising (c) subjecting the second high-boilers stream to wiped-film evaporation (WFE) producing a second WFE distillate and subjecting the second WFE distillate to step (d) and optionally further comprising (e) treating the first 1,4-BDO-containing product stream with a hydrogenation reaction prior to performing step (b); <EOS>