From: Microbial synthesis of poly-γ-glutamic acid: current progress, challenges, and future perspectives
Starting sources | Fermentation strategies | Main results | Ref. |
---|---|---|---|
B. licheniformis NCIM 2324 | Optimization via one factor at a time | γ-PGA production increased from 5.27 to 26.12 g/L | [89] |
B. subtilis CGMCC 0833 | Applying pH-shift control strategy | Glutamate utilization increased from 24.3 to 29.5 g/L; γ-PGA production increased from 22.2 to 27.7 g/L | [62] |
B. subtilis NX-2 | Using a two-stage strategy for agitation speed control | The concentration of γ-PGA reached 40.5 g/L with increases of 17.7 % | [90] |
B. subtilis NX-2 | Adding different oxygen vectors | The concentration of γ-PGA reached 39.4 g/L with increase of 25.1 % | [59] |
B. subtilis BL53 | Adding some precursors | The production of γ-PGA increased to 25.2 g/L | [91] |
B. subtilis C10 | Addition of organic acid | The concentration of γ-PGA increased from 17.3 to 27.7 g/L | [92] |
B. licheniformis NCIM 2324 | Addition of metabolic precursors | The concentration of γ-PGA reached 35.75 from 26.12 g/L | [81] |
B. licheniformis TISTR 1010 | Using different feeding strategies | The γ-PGA concentration reached 27.5 g/L with increase of fivefold | [83] |
B. subtilis NX-2 | Using co-fermentation strategy | The production and productivity of γ-PGA reached 73.0 g/L and 0.81 g/L/h, respectively | [50] |
B. subtilis CCTCC M 2012347 | Solid-state fermentation | Using soybean residue and cane molasses to produce 103.5 g/kg of γ-PGA at 24 h under non-sterilized condition | [93] |
B. amyloliquefaciens C1 | Solid-state fermentation | Producing 0.0437 g γ-PGA per gram of substrates at 48 h | [94] |
B. subtilis GXA-28 | Addition of KCl | The γ-PGA yield increased from 18.36 to 25.62 g/L by 39.5 % | [95] |
B. licheniformis | Heat stress and alkaline stress treatment | The maximum γ-PGA yield reached 29.34 g/L, 185 % higher than the control | [78] |
B. licheniformis WX-02 | Alkaline pH stress treatment | The maximum γ-PGA yield reached 36.26 g/L in the 50 L bioreactor, increased by 79 % compared with the control | [96] |
B. subtilis NX-2 | Adding hydrogen peroxide | The maximum concentration of 33.9 g/L γ-PGA was obtained by adding 100 µM H2O2 to the medium after 24 h. This concentration was 20.6 % higher than that of the control | [97] |