Oxygen transfer effects in serine alkaline protease fermentation by Bacillus licheniformis: use of citric acid as the carbon source

Fermentation and oxygen transfer characteristics in recombinant human growth hormone production by Pichia pastoris in sorbitol batch and methanol fed‐batch operation

“…16 It had a tendency to increase at the beginning of the process with the rise in cell concentration, and then reached a maximum at t = 9-15 h of the bioprocess, having OUR values for MS-0.02, 0.03, and 0.04 conditions at 18.5, 34.1, 76.6 mmol m −3 s −1 , respectively.…”

“…RhGH concentration was determined by high-performance capillary electrophoresis (HPCE) (Waters, Quanta 4000E, Milford, MA) using the method developed for the determination of protein concentrations. 16 Excreted amino acid concentrations were measured with an amino acid analysis system (Waters HPLC), using the modified Pico Tag method. 17 Excreted organic acid concentrations were measured with an HPLC (Waters-2695).…”

“…19 SDS-PAGE was performed as described by Laemmli. 20 Protease activity was measured spectrophotometrically, 16 …”

A salt, detergent, and solvent tolerant protease from <i>Bacillus</i> sp. B001: Low-cost, easy-purified, and enhanced production by raw material based culture strategy

“…Besides, MgSO 4 , KH 2 PO 4 , and CaCl 2 , which were added and optimized together in the flowing steps, could enhance the protease accumulation (data not shown). It has been shown that metabolizable carbon sources and organic nitrogen sources rich in amino acids and short peptides may repress enzyme production when higher concentrations were applied [12,15,[23][24][25]. In order to relieve catabolite repression, Beg et al [24] adopted an intermittent derepression and induction fed-batch strategy by separating biomass accumulation and protease production phases.…”

“…In order to relieve catabolite repression, Beg et al [24] adopted an intermittent derepression and induction fed-batch strategy by separating biomass accumulation and protease production phases. In another case, citric acid was used to substitute glucose as the carbon source for alkaline protease production form B. licheniformis DSM 1969 [23]. In this study, we proposed to introduce a raw material based culture strategy on the basis that raw materials contained complex polymeric nutrients which were slowly hydrolyzed to metabolizable substrates by exoenzymes, thus high concentrations of which may be adopted without exerting catabolite repression.…”