Improved Polysaccharide Production Using Strain Improvement

A strain improvement procedure is outlined for the isolation of mutant strains from the bacterium Pseudomonas sp. ATCC 31461 that are capable of enhanced production of the polysaccharide gellan compared to its parent strain. With gellan having a number of industrial applications, the isolation of such mutant strains could prove valuable to its large-scale production. The mutant strains are isolated using a procedure that involves chemical mutagenesis and screening for resistance to the antibiotic ampicillin, with possible mutants being selected based on their mucoid appearance on the antibiotic-containing solid medium. The mutant strains were identified by following protocols using gravimetric determinations to measure the concentrations of gellan and cellular biomass. The viscosimetric properties of the mutant strain were compared to its parent strain by measuring the viscosities of their whole-culture medium and crude polysaccharide using procedures outlined.