Production of carboxymethyl-cellulase by high density cell culture with bacillus megaterium pCK108

Abstract

For the high production of carboxymethyl cellulase (EC 3.2.1.4) by a recombinant cell, Bacillus megaterium pCK108, exponential feeding fed-batch culture for high density cell cultivation was carried out. In the culture system, specific growth rate, could be controlled by manipulating a feed rate of fresh medium under the condition of the carbon limitation. From the various rate of experiments, it was found that specific rate of enzyme production was decreased with an increase of specific growth rate. In order to obtain a high production of enzyme, the concentration of glucose in feed stream was increased 50g/1 to 200g/1. When glucose concentration was increased the cell concentration was proportionally increased. However but enzyme production was not increased proportionally but slightly; i.e. ezyme production was 3.18 U/ml with 14.5 g/l of cell at 50g/l of glucose and it was 3.52 U/ml with 46.7 g/l of cell at 200g/1 of glucose. Overall cell growth yield also decreased slightly from 0.40 to 0.35 at a high concentration of glucose. It was also convincedthat protease accumulated in the culture broth did not affect the degradation of carboxymethyl cellulase during fermentation. As a nitrogen source, ammonium sulfate was superior to other inorganic nitrogen sources tested in terms of enzyme production.