The present invention provides a method for producing L-amino acids such as L-amino acids belonging to the glutamate family by fermentation using a bacterium of the family Enterobacteriaceae, particularly a bacterium belonging to the genus Escherichia, which has been modified to disrupt the putrescine degradation pathway by, for example, inactivation of one gene or several genes from the puuADRCBE gene cluster.

Provided is a novel production system for a product selected from a nitrogen-containing product and a fermented and cultured product that does not involve (or can minimize) the transport of liquid ammonia. A production system for a product selected from a nitrogen-containing product and a fermented and cultured product can include: an ammonia synthesis apparatus in which an ammonia-containing gas is synthesized by reaction of a source gas containing hydrogen and nitrogen in the presence of a supported metal catalyst containing as a support one or more selected from the group consisting of: i) a conductive mayenite compound; ii) a two-dimensional electride compound or a precursor thereof; and iii) a complex formed of a support base containing at least one metal oxide selected from ZrO.sub.2, TiO.sub.2, CeO.sub.2, and MgO and a metal amide represented by a formula M(NH.sub.2).sub.x (where M represents one or more selected from Li, Na, K, Be, Mg, Ca, Sr, Ba, and Eu; and x represents a valence number of M) supported by the support base; and a production apparatus that produces a product selected from a nitrogen-containing product and a fermented and cultured product using ammonia originating from the ammonia-containing gas obtained by using the ammonia synthesis apparatus.

Provided is a novel production system for a product selected from a nitrogen-containing product and a fermented and cultured product that does not involve (or can minimize) the transport of liquid ammonia. A production system for a product selected from a nitrogen-containing product and a fermented and cultured product can include: an ammonia synthesis apparatus in which an ammonia-containing gas is synthesized by reaction of a source gas containing hydrogen and nitrogen in the presence of a supported metal catalyst containing as a support one or more selected from the group consisting of: i) a conductive mayenite compound; ii) a two-dimensional electride compound or a precursor thereof; and iii) a complex formed of a support base containing at least one metal oxide selected from ZrO.sub.2, TiO.sub.2, CeO.sub.2, and MgO and a metal amide represented by a formula M(NH.sub.2).sub.x (where M represents one or more selected from Li, Na, K, Be, Mg, Ca, Sr, Ba, and Eu; and x represents a valence number of M) supported by the support base; and a production apparatus that produces a product selected from a nitrogen-containing product and a fermented and cultured product using ammonia originating from the ammonia-containing gas obtained by using the ammonia synthesis apparatus.

Provided is a novel production system that does not involve, or can minimize, the transport of liquid ammonia in the production of an organic compound or the production of a microorganism by microbial fermentation. A production system for an organic compound or a microorganism includes: an ammonia synthesis apparatus in which an ammonia-containing gas is synthesized by reaction of a source gas containing hydrogen and nitrogen in the presence of a supported ruthenium catalyst; and a culture apparatus that cultures a microorganism having organic compound productivity using ammonia originating from the ammonia-containing gas obtained by using the ammonia synthesis apparatus.

Provided is a novel production system that does not involve, or can minimize, the transport of liquid ammonia in the production of an organic compound or the production of a microorganism by microbial fermentation. A production system for an organic compound or a microorganism includes: an ammonia synthesis apparatus in which an ammonia-containing gas is synthesized by reaction of a source gas containing hydrogen and nitrogen in the presence of a supported ruthenium catalyst; and a culture apparatus that cultures a microorganism having organic compound productivity using ammonia originating from the ammonia-containing gas obtained by using the ammonia synthesis apparatus.

An acetyl-CoA producing microorganism obtained by imparting at least one enzymatic activity selected from the group consisting of malate thiokinase, malyl-CoA lyase, glyoxylate carboligase, 2-hydroxy-3-oxopropionate reductase, and hydroxypyruvate reductase, to a microorganism that does not have any of the following (a), (b), (c), (d) or (e): (a) a carbon dioxide fixation cycle including an enzymatic reaction from malonyl-CoA to malonate semialdehyde or 3-hydroxypropionate; (b) a carbon dioxide fixation cycle including an enzymatic reaction from acetyl-CoA and CO.sub.2 to pyruvate; (c) a carbon dioxide fixation cycle including an enzymatic reaction from crotonyl-CoA and CO.sub.2 to ethylmalonyl-CoA or glutaconyl-CoA; (d) a carbon dioxide fixation cycle including an enzymatic reaction from CO.sub.2 to formate; or (e) at least one selected from the group consisting of malate thiokinase and malyl-CoA lyase.

An acetyl-CoA producing microorganism obtained by imparting at least one enzymatic activity selected from the group consisting of malate thiokinase, malyl-CoA lyase, glyoxylate carboligase, 2-hydroxy-3-oxopropionate reductase, and hydroxypyruvate reductase, to a microorganism that does not have any of the following (a), (b), (c), (d) or (e): (a) a carbon dioxide fixation cycle including an enzymatic reaction from malonyl-CoA to malonate semialdehyde or 3-hydroxypropionate; (b) a carbon dioxide fixation cycle including an enzymatic reaction from acetyl-CoA and CO.sub.2 to pyruvate; (c) a carbon dioxide fixation cycle including an enzymatic reaction from crotonyl-CoA and CO.sub.2 to ethylmalonyl-CoA or glutaconyl-CoA; (d) a carbon dioxide fixation cycle including an enzymatic reaction from CO.sub.2 to formate; or (e) at least one selected from the group consisting of malate thiokinase and malyl-CoA lyase.

An acidic substance having a carboxyl group is produced by culturing in a medium a microorganism which has been modified to enhance expression of the ybjL gene, and collecting the acidic substance having a carboxyl group from the medium.

An acidic substance having a carboxyl group is produced by culturing in a medium a microorganism which has been modified to enhance expression of the ybjL gene, and collecting the acidic substance having a carboxyl group from the medium.

An acetyl-CoA-producing microorganism, which is capable of efficiently synthesizing acetyl-CoA using carbon dioxide, and a substance production method using the same are provided. An acetyl-CoA-producing microorganism including an acetyl-CoA production cycle obtained by imparting at least one type of enzymatic activity selected from the group consisting of malate thiokinase, malyl-CoA lyase, glyoxylate carboligase, 2-hydroxy-3-oxopropionate reductase, and hydroxypyruvate reductase, to a microorganism.