Fermentation and oxygen transfer characteristics in serine alkaline protease production by recombinant Bacillus subtilis in molasses‐based complex medium

Abstract

Serine alkaline protease (SAP) production in a complex medium based on physically pretreated molasses by recombinant Bacillus subtilis carrying pHV1431::subC gene is described. The effects of oxygen transfer were investigated in 3.5 dm 3 bioreactor systems with controls for agitation rate, dissolved oxygen, pH, temperature, and foam formation under two different agitation rates, ie N = 500 and 750 min Keywords: serine alkaline protease; Bacillus; recombinant; molasses; oxygen transfer characteristics; oxygen transfer rate; oxygen transfer coefficientDamköhler number (= OD/OTR max ; maximum possible oxygen utilisation rate per maximum oxygen transfer rate) m O Maintenance coefficient of oxygen (kg kgSucrose metabolised per amount of oxygenSpecific cell yield on substrate (kg kg −1 ) η Effectiveness factor (= OUR/OD; the oxygen uptake rate per maximum possible oxygen utilisation rate) * Correspondence to: GüzideÇalık, Department of Chemical Engineering, and Industrial Biotechnology Department of Biotechnology Research Center, Ankara University, Tandoǧan, 06100 Ankara, Turkey E-mail: calik@eng.ankara.edu.