A genetically modified Escherichia coli for the production of 1,4-butanediol by exclusively converting xylose into 1,4-butanediol, wherein said microorganism further comprises: i) the deletion of the following endogenous genes: - the xylA gene encoding a xylose isomerase, - the xylB gene encoding a xylulose kinase, - the yjhH and yagE genes encoding a 3-deoxy-D-glycero-pentulosonate aldolase, - the yiaE and ycdW genes encoding a keto-acid dehydrogenase, thereby providing reducing power and/or energy for 1,4-butanediol production and microorganism growth from a carbon source other than xylose, and ii) at least one of the following genetic modifications at least partially inhibiting carbon catabolite repression: - deletion of the endogenous ptsG gene encoding a glucose phophotransferase, - deletion of the endogenous ptsH gene encoding a phosphocarrier Hpr protein, - expression of the endogenous lacY gene and/or the endogenous malFG and/or cscBKAR operon or the heterologous scrKYABR operon from Salmonella typhimurium, involved in a sugar importer system wherein said sugar is a carbon source other than xylose, - expression of the endogenous xylFGH operon encoding an ABC xylose transporter, - overexpression of the endogenous galP gene encoding a glucose permease, - overexpression of the heterologous glf gene encoding a glucose facilitator from Zymomonas mobilis, - overexpression of the endogenous glk gene encoding a glucokinase, - expression of a gene encoding a cAMP-independent CRP protein, wherein said CRP protein is coded by SEQ ID NO: 28, 29, 30, 31, or 32, and - any combination thereof, thereby optimizing the production of 1,4-butanediol by said microorganism. i) the deletion of the following endogenous genes: - the xylA gene encoding a xylose isomerase, - the xylB gene encoding a xylulose kinase, - the yjhH and yagE genes encoding a 3-deoxy-D-glycero-pentulosonate aldolase, - the yiaE and ycdW genes encoding a keto-acid dehydrogenase, thereby providing reducing power and/or energy for 1,4-butanediol production and microorganism growth from a carbon source other than xylose, and - the xylA gene encoding a xylose isomerase, - the xylB gene encoding a xylulose kinase, - the yjhH and yagE genes encoding a 3-deoxy-D-glycero-pentulosonate aldolase, - the yiaE and ycdW genes encoding a keto-acid dehydrogenase, thereby providing reducing power and/or energy for 1,4-butanediol production and microorganism growth from a carbon source other than xylose, and ii) at least one of the following genetic modifications at least partially inhibiting carbon catabolite repression: - deletion of the endogenous ptsG gene encoding a glucose phophotransferase, - deletion of the endogenous ptsH gene encoding a phosphocarrier Hpr protein, - expression of the endogenous lacY gene and/or the endogenous malFG and/or cscBKAR operon or the heterologous scrKYABR operon from Salmonella typhimurium, involved in a sugar importer system wherein said sugar is a carbon source other than xylose, - expression of the endogenous xylFGH operon encoding an ABC xylose transporter, - overexpression of the endogenous galP gene encoding a glucose permease, - overexpression of the heterologous glf gene encoding a glucose facilitator from Zymomonas mobilis, - overexpression of the endogenous glk gene encoding a glucokinase, - expression of a gene encoding a cAMP-independent CRP protein, wherein said CRP protein is coded by SEQ ID NO: 28, 29, 30, 31, or 32, and - any combination thereof, thereby optimizing the production of 1,4-butanediol by said microorganism. - deletion of the endogenous ptsG gene encoding a glucose phophotransferase, - deletion of the endogenous ptsH gene encoding a phosphocarrier Hpr protein, - expression of the endogenous lacY gene and/or the endogenous malFG and/or cscBKAR operon or the heterologous scrKYABR operon from Salmonella typhimurium, involved in a sugar importer system wherein said sugar is a carbon source other than xylose, - expression of the endogenous xylFGH operon encoding an ABC xylose transporter, - overexpression of the endogenous galP gene encoding a glucose permease, - overexpression of the heterologous glf gene encoding a glucose facilitator from Zymomonas mobilis, - overexpression of the endogenous glk gene encoding a glucokinase, - expression of a gene encoding a cAMP-independent CRP protein, wherein said CRP protein is coded by SEQ ID NO: 28, 29, 30, 31, or 32, and - any combination thereof,