Optimization of Corynebacterium glutamicum immobilization process on bacterial cellulose carrier and its application for lysine fermentation

Abstract

Bacterial cellulose (BC) was used as a modern carrier in immobilization of cell. The immobilization of Corynebacterium glutamicum using bacterial cellulose (BC) as a carrier was carried out in two steps: adsorption and incubation. The screening method Plackett-Burman Design was used to identify the significantly influenced factors and the experiments were designed by Response Surface Methodology having the Central Composite Design (RSM-CCD). The obtained immobilization parameters were the cell density of 6.6 billion clone form units per milliliter, the weight of BC of 10g/100mL, the adsorption time of 6.82 hours with the shaking speed of 150 rpm and immobilized cell was incubated at 30 0 C for 3 days. The optimal efficiency of this immobilization reached 72.4% and the average density of cell on BC carrier was achieved 47.7 ± 0.02 billion clone form units per gram of finished product. These were fermented to receive L-lysine, the number reusing times of immobilized cell was eight, and the lysine field was 95% in the eighth time of reusing immobilized cell for fermentation with 26.032 ± 0.023 g/L and volumetric productivity was achieved 0.618 ± 0.100 g/(L.h). Furthermore, this immobile product was maintained under the suitable condition in the sterile water, pH = 7. After storing at 4 0 C for 30 days, the percentage of cell survival was 80%.