It is also used for medical purposes, such as encapsulation of cells. One example of the latter is the use of alginate for the encapsulation of insulin-producing cells for better treatment of patients suffering from diabetes. We have isolated alginate over-producing mutants of Pseudomonas fluorescens and are studying genes involved in the production of the polymer. We are also combining this knowledge with knowledge of different Pm-promoters (see Gene Expression) and of the alginate modifying enzymes to engineer production strains for different types of alginates.