Engineering microbial pathways for production of bio-based chemicals from lignocellulosic sugars: current status and perspectives

Table 3 Yield and energy cost of bio-based chemicals according to production pathways expressed in E. coli

Bio-based products	Production pathway	Substrat	Nbr reaction step	NAD(P)H yield (mole/mole)	ATP yield (mole/mole)	Pathway yield (Y^p)^$	Yield efficiency (%)^*
Ethylene glycol (EG)	NP-Dahms	Xylose	5	0	0	1	50
	Xylulose-1-P	Xylose	4	− 1	− 1	0.87	50
	Ribulose-1-P	Xylose	5	− 1	− 1	0.87	50
	Serine pathway	Glucose	13	+2	0	2	83.3
	X1P (R1P) + serine pathway	Xylose	7	+1	0	2	100
	X1P (R1P) + serine pathway	Xylose + glucose	11	+2	0	4	91
Glycolic acid (GA)	CCM- (GS)^$	Glucose	18	+6	+2	2	66
	NP-Dahms	Xylose	5	+2	0	1	40
	Xylulose-1-P	Xylose	4	+1	− 1	0.96	40
	Ribulose-1-P	Xylose	5	+1	− 1	0.96	40
	NP-Dahms + GS	Xylose	10	+2 (+1QH2)	0	2	80
	X1P (R1P) + GS	Xylose	9	+ 3 + (1QH2	+1	2	80
	X1P (R1P) + GS	Xylose + glucose	15	+2 + (3 QH2)	+3	4	73
1,4 Butanediol (BDO)	CCM^$	Glucose	21	0	0	1	92
1,4 Butanediol (BDO)	NP-Weimberg	Xylose	6	0	0	1	110
1,2,4 Butanetriol (BTO)	CCM^$	Glucose	17	0	-1	1	83
1,2,4 Butanetriol (BTO)	NP-KDC	Xylose	5	0	0	1	100
3,4 dihydroxybutyric acid (3,4-DHBA)	CCM	Glucose	22	+3	0	1	66
3,4 dihydroxybutyric acid (3,4-DHBA)	NP-KDC	Xylose	5	+2	0	1	80
Mesaconic acid (MSA)	CCM^$	Glucose	18	+3	+1	1	75
Mesaconic acid (MSA)	NP-Weimberg	Xylose	8	+1	0	1	91
Glutaric acid (GTA)	CCM^$	Glucose	17	+ 5.66	+1.33	1
Glutaric acid (GTA)	NP-Weimberg + XI	Xylose	14	+4	0	0.66	62

XI means xylose isomerase pathway
^$Y^p is the stoichiometry pathway efficiency strictly calculated from the pathway without balancing ATP and cofactors
*Yield efficiency is the ratio between the thermodynamic or energy yield and the pathway yield (Y^p) as defined by [72]. The energy yield of these chemicals as produced from pentose or glucose can be found in Additional file 1: Table S4
^$ CCM-GS means Carbon central metabolism—glyoxylate shunt

ISSN: 2731-3654