Studies of B -(1, 3)(1, 4)- Glucanase production by a recombinant yeast strain immobilised calcium alginate gel
Cahill, Gearoid
(1990)
Studies of B -(1, 3)(1, 4)- Glucanase production by a recombinant yeast strain immobilised calcium alginate gel.
Master of Science thesis, Dublin City University.
Production of the recombinant enzyme p - (1,3)(1,4) -
glucanase in Saccharomyces cerevisiae (DBY746), containing
the plasmid pJG317 was studied for both free cells and
cells immobilised in calcium alginate During prolonged
growth, glucanase production decreased exponentially in
the case of free cells No decrease in enzyme production
was observed for immobilised cells.
Plasmid stability of both free and immobilised cells was
studied The percentage of plasmid-containing cells in
suspension culture decreased to 24% in 96 hours. The
plasmid stability of cells throughout the immobilisation
matrix was measured. It was found that cells in the centre
of the gel beads retained the recombinant plasmid to a
greater degree than free cells, or cells at the surface of
the matrix.
Continuous stable production of p~glucanase by free
cells in non-selective medium was not possible. Enzyme
production by the immobilised yeast strain, however, was
stable for 10 days, with no sign of decrease. The enzyme
productivity for immobilised cells in a continuous reactor
(using non-selective medium), was 48 U/ml/h, compared to
3 6 U/ml/h for free cells in batch culture using nonselective medium.