Table 1.
Summary of metabolic engineering strategies for bacitracin production in B. licheniformis.
| Strains and genotypes | Strategies | Effects | References |
|---|---|---|---|
| Strengthening utilization ratio of substances | |||
| B. licheniformis DW2ΔPaprA | Enhancing the consumption ratio of soybean meal | Soybean meal utilization ratio increased by 28.86%; bacitracin titer increased by 18.92% | Cai et al., 2019a |
| Strengthening precursor amino acids | |||
| B. licheniformis DW2-ASP10 (ΔyveA,ΔaspA,ΔmalS, aspD*, ansB*, pycA*, ecaA*) | Strengthening the supply of aspartic acid | Aspartic acid titer increased by 394.47%; bacitracin titer increased by 40.10%; | Zhu et al., 2021 |
| B. licheniformis DW2-LYS5 (ΔyaaO,ΔlysE,ddh*, pycA*, lysA*, lysP*, yvsH*) | Strengthening lysine supply | Lysine titer increased by 52.78%; Bacitracin titer increased by 28.95%; | Wu et al., 2019 |
| B.licheniformis DW2ΔproBΔproJΔargR:ppnk1 | Strengthening ornithine supply | Ornithine titer increased by 71.40%; Bacitracin titer increased by 16.58%; | Yu et al., 2019 |
| B.licheniformis DW2-CYS4 (cysK*, cysE*, cysP*, tcyP*) | Strengthening cysteine supply | Cysteine titer increased by 46.36%; bacitracin titer increased by 21.10%; | Li et al., 2021 |
| B.licheniformis DW2-KENPND (ΔmetN,ΔspeD,ΔmtnN, metK*, metH*, metP*) | Strengthening S-Adenosylmethionine supply | SAM titer increased by 156%; bacitracin titer increased by 28.97%; | Cai et al., 2020a |
| B.licheniformis DW-BCAA6 (ΔlrpC, ilvBNfbr*, leuAfbr*,ybgE*, yvbW*, braB*) | Strengthening the supplies of branched chain amino acids | Isoleucine, leucine and valine increased by 226%, 190% and 72%, respectively; bacitracin titer increased by 36.52% | Cai et al., 2020b |
| B.licheniformis DW2Δlrp:brnQ | Strengthening the supplies of branched chain amino acids | Isoleucine, leucine and valine increased by 176.04%, 162.04%, 42.77%, respectively; bacitracin titer increased by 22.42% | Zhu et al., 2018 |
| B.licheniformis DW2ΔyhdG | Strengthening the supplies of branched chain amino acids | Isoleucine, leucine and valine increased by 627%, 590%, 536%, respectively; bacitracin titer increased by 22.42% | Li et al., 2018 |
| Strengthening ATP supply and NADPH generation | |||
| B.licheniformis DW2-CQD (ΔcydB, qoxA*,dcK*) | Strengthening ATP supply | ATP content increased by 49.32%; bacitracin titer increased by 21.66% | Zhang et al., 2020 |
| B.licheniformis BL2ST6 (vgb*, bacT*) | Strengthening oxygen availability and type II thioesterase | Bacitracin A titer increased by 36.84% | Wu et al., 2021 |
| B.licheniformis DW2:icd | Increased the flux through TCA cycle | ATP content increased by 73.7%; bacitracin titer increased by 11.5% | Liu et al., 2018 |
| B.licheniformis DW2:zwf | Strengthening NADPH generation | NADPH content increased by 61.24%; bacitracin titer increased by 12.43% | Zhu et al., 2019 |
| Transcription factor engineering | |||
| B. licheniformis DW2ΔabrB | Over-expression of bacA by inactivation of AbrB | Bacitracin titer increased by 17.50%; | Wang et al., 2017 |
| B.licheniformis DW2-CNCTGP (ΔccpC,ΔccpN,ΔphoP, tnrA*, codY*, glnR*) | Transcription factor engineering | ATP content increased by 60.65%; NADPH content increased by 54.74%; bacitracin titer increased by 35.72% | Cai et al., 2019b |