Table 1.

Recent examples of engineering Synthetic Microbial consortia.

Microorganism	Interaction	Goal to optimize	C-source	Yield	Ref.
Unidirectional Non-Distributed
Synechoccocus elongates Pseudomonas putida	S. elongatus produces sucrose from CO2 and light. It was used for P. putida, growing and cleaning 2,4-DNT while produces polyhydroxyalcanoates (PHA)	-Sucrose production in presence of 2,4-DNT -2,4-DNT cleaning -PHA production	CO2	-1.2 g/L sucrose at 120h. -250 mM 2,4-DNT cleaning at 24 h. -5.1 mg/L day PHA	[19]
S. elongatus Escherichia coli	S. elongatus produces sucrose from CO2 and light. The sucrose is used as C-source for E. coli, producing 3-hydroxypropinoic acid (3-HP)	-3-HP production -Sucrose production	CO2	-Up to 68.29 mg/L 3-HP at 7 days -600 mg/L sucrose at 144 h	[20]
Klebsiella pneumoniae Shewanella oneidensis	K. pneumoniae uses glycerol as C-source, producing lactate. S. oneidensis uses the lactate producing electrons.	-Lactate production -Flavin production (S. oneidensis) -Inoculum ratio -Electric power	Glycerol	-2.1-times increase lactate production -7.9-time increase flavin production -Inoculum ratio 1:10 -19.9 mW/m2 power density	[139]
Ralstonia eutropha Bacillus subtilis	B. subtilis hydrolyses sucrose in fructose and glucose, producing propionic acid. They are used by R. eutropha, producing PHA or poly (3-hydroxybutyrate-co-3hydroxyvalerate) [P(3HB-co-3HV].	-Biomass -PHA production -P(3HB-co-3HV) production	Sucrose	-Biomass 3.79 g dcw/L -PHA 63% w/w -P(3HB-co-3HV) 66% w/w	[140]
Citrobacter amalonaticus Sporomusa ovata	C. amalonaticus uses CO as carbon source, producing CO2 and H2 which are used by S. ovata producing acetate	-Acetate production	CO	-0.157 mM acetate from 0.439 mM CO	[141]
Trichoderma reesei Rhizopus delemar or T. ressei R. orizae	T. reesei hydrolyses cellulose into monomeric sugars. R. delemar uses these sugars producing fumaric acid and R. oizae producing lactic acid.	-Organic acids production	Corn stove	-6.87 g/L fumaric acid -4.4 g/L lactic acid	[142]
Clostridium thermocellum C. saccharoperbutylacetonicum	C. thermocellum hydrolyses cellulose releasing the C-source for butanol production by C. saccharoperbutylacetonicum.	-Butanol production	Rice straw	-6.5 g/L butanol from 40 g/L rice straw	[18]
E. coli Acinetobacter baylyi	E. coli utilizes glucose as C-source producing acetate. The acetate is used by A. baylyi	-E. coli biomass accumulation -Acetate removal	Glucose	-Increase of E. coli biomass from 2.1 g/l in monoculture to 5.1 g/l in co-culture -Acetate reduction from 13 mM to 3mM	[143]
T. reesei E. coli	T. reesei hydrolyses cellulose into monomeric sugars. E. coli uses these sugars producing isobutanol.	-Isobutanol production	Cellulose	-1.88 g/L from 20g/L cellulose	[21]
E. coli E. coli	E. coli E609Y produces xylanase extracellularly, hydrolysing xylan to xylooligosaccharides. they are used by E. coli KO11 producing ethanol.	-Xylane hydrolysis -Ethanol production	Xylan	-38.6% hydrolysis -3.71 g/L ethanol	[22]
Rhodotorula glutinis Dwbaryomyces castellii	D. castelli hydrolyses corn syrup into sugars, which are used by R. glutinis, producing carotenoids.	-Carotenoids production	Corn syrup	-8.2 mg/L carotenoids	[144]
Multidirectional Non-Distributed
E. coli Corynebacterium glutamicum	E. coli (Lys auxotroph) produces amylase extracellularly, hydrolysing starch into glucose, which is used by C. glutamicum, producing cadaverine or L-pipecolic acid (L-PA) and Lys, necessary for E. coli growth.	-Production of Lys and cadaverine or L-PA	Starch	-12.3 mM Lys -6.8 mM cadaverine or 3.4 mM L-PA	[23]
Sacharomyces cerevisiae -Bacillus. Amyloliquefacien or S. cerevisiae - Lactobacillus fermentum	B. amyloliquefaciens/L. fermentum produces amylase, hydrolysing starch into glucose and oligosaccharides. they are used by S. cerevisiae. Its growth stimulates the production of more amylase for B. amyloliquefaciens/L. fermentum.	-α-amylase production -Co-culture conditions	Starch	-1.8-times increase α-amylase production -Bacterial;yeast ratio of 1:125; Tª of 33.5°C and pH of 5.5	[145]
Streptomyces sp. Mg1B. subtilis	In co-culture B. subtilis stimulates Streptomyces sp Mg1 to produce chalcomycin A (macrolide antibiotic). Chalcomycin A inhibits B subtilis growth.	-Chalcomycin A	Maltose	-n.d.	[24]
P. putida - Bdellovibrio bacteriovorus	P. putida producing PHA and polyhydroxybutyrate (PHB) was mixed with the predatory B. bacteriovorus, that feeds on P. putida, releasing the PHA or PHA to the medium.	-PHA and PHB	octanoate	-80 % recovery in the extracellular medium	[146]
Pseudomonas aeruginosa -Buskholderia cenocepacia	In co-culture at limited iron P. aeruginosa and B. cenoceparia competed for the iron, limiting the growth of B. cenoceparia. When a P. aeruginosa iron cheater mutant was introduced both strains grew well at limited iron	-population fitness	Casamino acids	-Increase in the growth of B. cenoceparia	[25]
P. aeruginosa Enterobacter aerogenes	E. aerogenes use glucose, producing 2,3-butanediol which is used by P. aeruginosa producing phenazines, They are used for E. aerogenes as electron acceptor.	-Electric density	Glucose	-14-times increase of the electric density	[147]
Unidirectional Distributed
E. coli S. cerevisiae	Hydrogel compartmentalized E. coli and S. cerevisiae were co-cultured, using glucose as C-source, E. coli produces L-DOPA, that is used by S. cerevisiae to produce betaxhantins	-Stability of the compartmentalized consortium -Inoculum ratio -Betaxhanthins production	Glucose	-Up to 10 times reutilization of the compartmentalized consortium -Inoculum S. cerevisiae:E. coli ratio of 6:1 -Optimized betaxhantin production	[148]
Three E. coli strains	The rosmarinic acid biosynthetic pathway was divided in three E. coli strains, one producing caffeic acid, other salvinic acid, and a third strains that use those intermediaries to produce rosmarinic acid. All of them use glucose as carbon source	-Rosmarinic acid	Glucose	-172 mg/L rosmarinic acid	[30]
E. coli E.coli	The glutarate biosynthetic pathway from Lys was splitted in two E. coli strains. The first one use Lys, producing 5-aminovaleric acid, that is used by the second E. coli strain producing glutarate	-Glutarate production	Lysine	-43.8 g/L glutarate	[149]
E. coli E.coli	E. coli RES produces resveratrol from p-coumarate. The resveratrol is glycosylated by E. coli RGL. Both strains use glucose as carbon source.	-Resveratrol glucosides	Glucose	-92 mg/L resveratrol glucosides	[28]
Halomonas sp. HL-48 Marinobacter sp. HL-58	When both strains are growing using glucose as carbon source they compete for it. When xylose is used instead of glucose, Halomonas consumes xylose, producing metabolites that are used for Marinobacter growth.	-Growth	Xylose	-Changed from competitive to cooperative interaction the growth was improved in co-culture	[150]
E. coli E. coli	E. coli P2C produces Tyr and p-coumarate from glucose. Both are used for E. coli BLNA to produce naringenin using glucose as carbon source	-Inoculation ratio -Naringenin production	Glucose	-P2C:BLNA ratio 1:5 -41.5 mg/L naringenin at 36 h	[27]
Four strains of E. coli	The synthetic plants pathway to produce Anthocyanins was divided and inserted in four different E. coli strains. The first produces phenylpropanoic acid, that is used for the second, producing flavonones. A third strain produces flavan-3-ols from flavonones. Finally, the last E. coli strain produces anthocyanins from flavan-3-ols.	-Anthocyanins production	Glucose	-9 mg/L anthocyanidin-3-O-glucosides	[31]
E. coli E. coli	The resveratrol biosynthetic pathway is divided in two E. coli strains. Both strains use glycerol as carbon source. One of them produces P-coumarate, which is used for the other to produce resveratrol.	-Resveratrol production	Glycerol	-22.6 mg/L resveratrol in 30 hours	[29]
E. coli S. cerevisiae	E. coli utilizes xylose as C-source, producing acetate which is the C-source for S. cerevisiae. In parallel, E. coli is producing taxadiene, that is oxygenated by S. cerevisiae.	-Co-culture stability -Oxygenated taxanes	Xylose	-33 mg/L oxygenated taxanes	[26]
E. coli E. coli	One E. coli strain uses xylose as C-source, producing 3-dehydroshikimic acid (DHS), uses for the other strain to produce muconic acid or 4-hydroxybenzoic acid, using glucose as C-source.	-Muconic acid -4-hydroxybenzoic acid	Glucose Xylose	-4.7 g/L of muconic acid -2.3 g/L of 4-hydroxybenzoic acid	[151]
Four strains of S. cerevisiae	The enzymatic pathway to produce ethanol from cellulose was divided in four S. cerevisiae strains.	-Ethanol production	Cellulose	-1.25 g/L of ethanol	[17]
Multidirectional Distributed
Dietzia sp strain DQ1245-1b Pseudomonas stutzeri SLG510A3-8	Dietzia uses hexadecane as C-source, producing hexadecanoid acid, α-ketoglutaric acid and R-3-hydroxybutanoic acid, that are used by P. stutzeri, that in turn produces glutamate and acetate for Dietzia. The consortium increase the diesel degradation	-Diesel biodegradation	Hexadecane	-85.54 % diesel removal	[152]
E. coli E. coli	One E. coli strain uses xylose, producing tyrosol. The other consumes glucose and produces salidroside (from tyrosol). The relationship between both strains had been stablished by cross-feeding. The xylose consuming strain is Phe auxotroph, while the glucose consuming is Tyr auxotroph.	-Salidroside production -C-source ratio -Inoculum ratio	Xylose Glucose	-6.03 g/L at 120 h fermentation -Glucose:xylose ratio 4:1 -Inoculum ratio tyrosol producer:salidroside producer 1:2	[32]
E. coli E. coli	One E. coli strain uses glucose as C-source, producing lysine. The other E. coli strain intakes the lysine producing cadaverine. This strain use glycerol as carbon source	-Cadaverine production -C-source ratio -Inoculum ratio -C:N ratio -Fermentation conditions	Glucose Glycerol	-Up to 28.5 g/L with constant feeding at 40 h -Glucose:glycerol ratio 8:1 -Strains ratio 10:1 -C:N ratio 3:2 -others	[153]
E. coli B. subtilis S. oneidensis	E. coli utilizes glucose as C-source, producing lactate and an electron donor; B. subtilis uses also glucose producing riboflavin as an electron shuttle. S. oneidensis uses the electron donor and the shuttle generating electricity and oxidizing lactate to acetate, which is used by E. coli and B. subtilis as C-source	-Electricity production	Glucose	-15 days production with an efficiency of 55.7%	[154]
S. oneidensis E. coli	E. coli ferments glucose producing formate, which is used by S. oneidensis, producing flavins, uses by E. coli. Their activity increase the electric current from cathode to anode in a MFC	-Current density	Glucose	-Increase of the current density to 2.0 μA/cm2.	[155]
E. coli E. coli	E. coli L is Leu auxotroph and E. coli K is Lys. They co-culture provide each other with the necessary amino acids, increasing the growth rate and the biomass.	-Growth	Glucose	-3-fold growth rate increase	[156]