Table 1 Strains, fermentation media, and control methods of the ten highest-yielding γ-GPA fermentation processes

B. subtilis ZJU-7

Isolated from fermented bean curd

Glucose, l-glutamate, yeast extract, NaCl, CaCl₂, MgSO₄, MnSO₄

10-L bioreactor, 300–800 rpm with 1.5 vvm, pH 6.5, 37 °C

[49]

B. subtilis NX-2

Using co-fermentation strategy

Glutamate, (NH4)₂SO₄, K₂HPO₄, MgSO₄, MnSO₄, and hydrolysis of rice straw

7.5-L bioreactor, 400 rpm with 1.2 vvm, initial pH 7.0, 32 °C

[50]

B. subtilis NX-2

Isolated from soil samples

Glucose, glutamate, (NH₄)₂SO₄, K₂HPO₄, MgSO₄, MnSO₄

7.5-L APFB for immobilized fermentation, 32 °C, pH 7.0

[42]

B. subtilis MJ80

Isolated from soil samples

Glutamic acid, starch, urea, citric acid, glycerol, NaCl, K₂HPO₄, MgSO₄, MnSO₄

3-L fermenter, 37 °C, 150 rpm with 1 vvm, initial pH 7.0

[56]

B. subtilis NX-2

Isolated from soil samples

Cane molasses and monosodium glutamate waste liquor

7.5-L bioreactor, 400 rpm at 1.2 vvm, 32 °C, pH 7.0

[55]

B. licheniformis P-104

Isolated from Chinese soybean paste

Glucose, sodium glutamate, sodium citrate, (NH4)₂SO₄, MnSO₄, MgSO₄, K₂HPO₄

7-L bioreactor, 500 rpm with 1.5 vvm, 37 °C, pH 7.0, fed-batch

[43]

B. licheniformis NCIM 2324

Addition of metabolic precursors

Glycerol, l-glutamic acid, citric acid, (NH4)₂SO₄, K₂HPO₄, MgSO₄, MnSO₄

250-mL flask, 200 rpm, 37 °C, initial pH 6.5

[81]

B. methylotrophicus SK19.001

Isolated from soil samples

Glucose, yeast extracts, MgSO₄, K₂HPO₄, MnSO₄

250 mL flask, 200 rpm, initial pH 7.2, 37 °C

[51]

B. subtillis HB-1

Isolated from soil samples

Glutamate, yeast extract, NaCl, MgSO₄, xylose, or corncob fibers hydrolysate

10-L bioreactor, 500 rpm, 37 °C, initial pH 6.5, fed-batch

[82]

B. licheniformis TISTR 1010

Using different feeding strategies

Glucose, citric acid, NH₄Cl, K₂HPO₄, MgSO₄, CaCl₂, MnSO₄, NaCl, Tween-80,

7-L fermenter, 300 rpm and 1 vvm, initial pH 7.4, 37 °C

[83]