Hydrolysing the soluble protein secreted by Escherichia coli in trans-4-hydroxy-L-proline fermentation increased dissolve oxygen to promote high-level trans-4-hydroxy-L-proline production

Figures & data

Figure 1. The catalysis of proline-4-hydroxylase.

Figure 2. Effect of different protease types and concentrations on the OD₆₀₀, protein content, and trans-4-hydroxy-L-proline concentration in the fermentation broth. (a) Alkaline protease; (b) neutral protease; (c) trypsin; (d) complex protease.

Figure 3. Effect of trypsin addition time on the fermentation of trans-4-hydroxy-L-proline. (a) OD₆₀₀ and protein content; (b) trans-4-hydroxy-L-proline concentration and acetic acid accumulation.

Figure 4. Effect of trypsin addition on trans-4-hydroxy-L-proline production. CF is control fermentation (no protease added); APF is added-protease fermentation (trypsin was added at 18 h). (a) Stirring speed, aeration and dissolved oxygen; (b) OD₆₀₀ and protein content; (c) Hyp concentration and glucose conversion rate; (d) acetic acid concentration and production rate.

Figure 5. Effect of APF on trans-4-hydroxy-L-proline production metabolic flux. The metabolic flux of CF is represented in black font, and the metabolic flux of CF is represented in red font.