Effective extracellular production of Bacillus stearothermophilus esterase by pH-stat modal fed-batch culture of recombinant Bacillus brevis.

摘要: An automated two-component substrate feeding strategy with a pH-stat modal fed-batch culture using high pH limit was developed to effectively produce esterase from hyperprotein-excreting Bacillus brevis HPD31 harboring plasmid pHSC131 which carries stearothermophilus gene. First, the effect of single- and multi-substrate feedings on growth activity excreted investigated. Then (polypepton + glucose) different feed rates studied. Highest (34 U/mL) obtained when concentrations polypepton glucose in nutrient solution were 250 41.60 g/L respectively. The absence excessive amount ineffective for extracellular formation because without increase cell concentration minimum while favored at expense production. It is believed that mechanism enzyme excretion dependent higher host unfavorable rate, automatically controlled by direct signal change, 0.30 mL/pulse found optimum production lower (0.15 mL/pulse) (0.67 did not good results. increased more than eight times 4 U/mL conventional batch 34 this study. productivity likewise threefold.