Provided is a method for producing 1,3-propanediol by means of fermentation of a recombinant microorganism. First, a recombinant microorganism is provided; the recombinant microorganism can overexpress acetyl-CoA carboxylase genes: accBC and accDA, a malonyl-CoA synthetase gene: mcr, a 3-hydroxypropionyl-CoA synthetase gene: pcs, a 3-hydroxypropionyl-CoA reductase gene: pduP, and a 1,3-propanediol reductase gene: yqhD. The recombinant microorganism is subjected to fermentation culture in a flask or fermentor using glucose ad as raw material to obtain the 1,3-propanediol. The recombinant microorganism can utilize low-cost glucose, sucrose, molasses, xylose and the like as raw material in the fermentation process, without additional expensive vitamin B12. Thus, cost of the production is significantly reduced, and there is a promising prospect in market.

Described is a method for the production of 3-buten-2-one comprising the enzymatic conversion of 4-hydroxy-2-butanone into 3-buten-2-one by making use of an enzyme catalyzing 4-hydroxy-2-butanone dehydration, wherein said enzyme catalyzing 4-hydroxy-2-butanone dehydration is (a) a 3-hydroxypropiony-CoA dehydratase (EC 4.2.1.116), (b) a 3-hydroxybutyryl-CoA dehydratase (EC 4.2.1.55), (c) an enoyl-CoA hydratase (EC 4.2.1.17), (d) a 3-hydroxyoctanoyl-[acyl-carrier-protein] dehydratase (EC 4.2.1.59), (e) a crotonyl-[acyl-carrier-protein] hydratase (EC 4.2.1.58), (f) a 3-hydroxydecanoyl-[acyl-carrier-protein] dehydratase (EC 4.2.1.60), (g) a 3-hydroxypalmitoyl-[acyl-carrier-protein] dehydratase (EC 4.2.1.61), (h) a long-chain-enoyl-CoA hydratase (EC 4.2.1.74), or (i) a 3-methylglutaconyl-CoA hydratase (EC 4.2.1.18). The produced 3-buten-2-one can be further converted into 3-buten-2-ol and finally into 1,3-butadiene.

Described is a method for the conversion of 3-methylcrotonyl-CoA into 3-hydroxy-3-methylbutyric acid comprising the steps of:

(a) enzymatically converting 3-methylcrotonyl-CoA into 3-hydroxy-3-methylbutyryl-CoA; and
(b) further enzymatically converting the thus produced 3-hydroxy-3-methylbutyryl-CoA into 3-hydroxy-3-methylbutyric acid
wherein the enzymatic conversion of 3-hydroxy-3-methylbutyryl-CoA into 3-hydroxy-3-methylbutyric acid according to step (b) is achieved by first converting 3-hydroxy-3-methylbutyryl-CoA into 3-hydroxy-3-methylbutyryl phosphate and then subsequently converting the thus produced 3-hydroxy-3-methylbutyryl phosphate into 3-hydroxy-3-methylbutyric acid.

Provided is a method for producing 1,3-propanediol by means of fermentation of a recombinant microorganism. First, a recombinant microorganism is provided; the recombinant microorganism can overexpress acetyl-CoA carboxylase genes: accBC and accDA, a malonyl-CoA synthetase gene, mcr, a 3-hydroxypropionyl-CoA synthetase gene: pcs, a 3-hydroxypropionyl-CoA reductase gene: pduP, and a 1,3-propanediol reductase gene: yqhD. The recombinant microorganism is subjected to fermentation culture in a flask or ferment or using glucose ad as raw material to obtain the 1,3-propanediol. The recombinant microorganism can utilize low-cost glucose, sucrose, malasses, xylose and the like as raw material in the fermentation process, without additional expensive vitamin B12. Thus, cost of the production is significantly reduced, and there is a promising prospect in market.

Described is a method for the conversion of 3-methylcrotonyl-CoA into 3-hydroxy-3-methylbutyric acid comprising the steps of: (a) enzymatically converting 3-methylcrotonyl-CoA into 3-hydroxy-3-methylbutyryl-CoA; and (b) further enzymatically converting the thus produced 3-hydroxy-3-methylbutyryl-CoA into 3-hydroxy-3-methylbutyric acid wherein the enzymatic conversion of 3-hydroxy-3-methylbutyryl-CoA into 3-hydroxy-3-methylbutyric acid according to step (b) is achieved by first converting 3-hydroxy-3-methylbutyryl-CoA into 3-hydroxy-3-methylbutyryl phosphate and then subsequently converting the thus produced 3-hydroxy-3-methylbutyryl phosphate into 3-hydroxy-3-methylbutyric acid.

Provided herein are genetically engineered microbes that include at least a portion of a carbon fixation pathway, and in one embodiment, use molecular hydrogen to drive carbon dioxide fixation. In one embodiment, the genetically engineered microbe is modified to convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof at levels greater than a control microbe. Other products may also be produced. Also provided herein are cell free compositions that convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof. Also provided herein are methods of using the genetically engineered microbes and the cell free compositions.

Provided herein are genetically engineered microbes that include at least a portion of a carbon fixation pathway, and in one embodiment, use molecular hydrogen to drive carbon dioxide fixation. In one embodiment, the genetically engineered microbe is modified to convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof at levels greater than a control microbe. Other products may also be produced. Also provided herein are cell free compositions that convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof. Also provided herein are methods of using the genetically engineered microbes and the cell free compositions.