Contninuous glutamate production using an immobilized whole-cell system.
An immobilized whole-cell system was prepared for the continuous production of glutamate in a continuous reactor system. Whole cells of Corynebacterium glutamicum (a mutant strain of ATCC 13058) were immobilized in a 4% (w/v) kappa-carrageenan solution dissolved in 0.9% saline and gelated at 10 deg before being cut into cubes and soaked in cold 0.3 M KCl solution to increase the gel strength. Immobilized cells were activated by incubation in a culture medium to give good growth in the gels. Glutamate was produced in an air-stirred fermentor, maximum substrate assimilation was about 90 mg glucose m1/gel/hr and the maximum cell concentration was 53.0 mg dry wt. cell/m1 after 48 hr activation. The optimal pH was at 7.2 and the maximum glutamate productivity was 1.08 g/1/hr. The gel-immobilized cells were stable under prolonged ontinuous fermentation for a period of 30 days. The performance of the continuous reactor system was far superior to that of conventional batch reactor systems and showed promise for the economical production of amino acids.