Table 1 Advanced biofuels using 2-keto acid intermediates

Isobutanol

E. coli [146], C. glutamicum [146], C. crenatum [17], Bacillus subtilis [146], Brevibacterium flavum [147] and S. cerevisiae [148]

IlvC, IlvD Kivd,adh2

B. subtilis, S. cerevisiae

Type I

2-Ketoisovalerate

2-Methyl-1-butanol

E. coli [8], C. crenatum [32], C. glutamicum [21] and S. cerevisiae [22]

IlvC,IlvD;Kivd,adh2

B. subtilis

Type I

2-Keto-3-methylvalerate

3-Methyl-1-butanol

E. coli [149], C. crenatum [23], cyanobacteria [150] and S. cerevisiae [151]

IlvC,IlvD;Kivd,adh2;LeuABCD

B. subtilis, S. cerevisiae

Type II

2-Keto-4-methyl-

valerate

4-Methyl-1-pentanol

E. coli [152], S. cerevisiae [153]

IlvC, IlvD;Kivd,adh2;

LeuABCD

B. subtilis, S. cerevisiae

Type II

2-Keto-5-methyl-hexnoate

3-Methyl-pentanol

E. coli [23], S. cerevisiae [154]

IlvC, IlvD;Kivd,adh2;

LeuABCD

B. subtilis, S. cerevisiae

Type II

2-Keto-5-methyl-hexnoate

5-Methyl-heptanol

E. coli [107], S. cerevisiae [23]

IlvC,,IlvD;Kivd,adh2;

LeuABCD

B. subtilis, S.cerevisiae

Type II

2-Keto-6-methyl-octanoate

Propanol

E. coli [155], C. glutamicum [156], S. cerevisiae [157]

IlvC, IlvD;Kivd, adh2;

LeuABCD

B. subtilis, S. cerevisiae

Type III

2-Ketobutyrate

Butanol

E. coli [27], S.cerevisiae [158], C. acetobutylicum [159],C.beijerinckii [160]

Acetyl-CoA acetyltransferase, 3-hydroxybutyryl-CoA dehydrogenase,crotonase,butyryl-CoA dehydrogenase

B. subtilis, S. cerevisiae

Type III

2-Ketovalerate

Pentanol

E. coli [161], S. cerevisiae [162]

IlvC,IlvD;Kivd,adh2;

LeuABCD

B. subtilis, S. cerevisiae

Type III

2-Ketocaproate

Hexanol

E. coli [163, 164], S. cerevisiae [163]

IlvC,IlvD;Kivd,adh2;

LeuABCD

B. subtilis, S. cerevisiae

Type III

2-Ketoheptanoate

Heptanol

E. coli [165], S. cerevisiae [166]

IlvC,IlvD;Kivd,adh2;

LeuABCD

B. subtilis, S. cerevisiae

Type III

2-Ketooctanoate

Octanol

E. coli [167, 168], S. cerevisiae [169]

IlvC,IlvD;Kivd,adh2;

LeuABCD

B. subtilis, S. cerevisiae

Type III

2-Ketononaoate