Fedbatch fermentations of Bacillus subtilis ToC46 (pPFF1) for the synthesis of a recombinant β-1,3-glucanase:: Experimental study and modelling

The behavior of the recombinant system Bacillus subtilis ToC46(pPFF1) for recombinant beta-1,3-glucanase enzyme synthesis was studied in batch and fedbatch fermentations. The effect of different nutrient feeding strategies on the synthesis of beta-1,3-glucanase and protease enzymes was studied The experimental data was used to find a mathematical model of the system. Different mathematical expressions for the synthesis kinetics of both enzymes were tested and values of the parameters involved were calculated. The results show that the mathematical expression for the recombinant enzyme synthesis rate is inversely proportional to glucose concentration which is the growth-limiting carbon source. Final recombinant enzyme activity in a fedbatch operation can be increased up to ten times compared with the concentration obtained at the end of a batch fermentation. Protease activity does not show significant changes under the operational conditions rested. (C) 1999 Elsevier Science Inc.