GENETIC IMPROVEMENT OF BACTERIA SPHINGOMONAS PAUCIMOBILIS ISOLATE TO INCREASE GELLAN PRODUCTION AND ITS VISCOSITY

Abstract

To improve the production of gellan and its quality, some genetic improvements were conducted on the bacteria Sphingomonas paucimobilis. Two methods of mutations were applied, the first was the physical mutation using ultraviolet radiation and the other was the combination of physical and chemical mutation using ultraviolet radiation and ethyl methyl sulfonate (EMS) which applied on the ampicillin resistant strain. Results showed that using ultraviolet radiation resulted in producing colorless and more viscose colonies and the strain treated with uv radiation for 2.5 min produced 6.64 gm of gellan/liter of medium which was 11% more gellan compared to the parent strain which produced 6.02 gm/l. Gellan viscosity of the new strain was 3500 C.P compared to the viscosity 3212 C.P of the parent strain. On the other hand, the mutation by uv radiation and EMS of the ampicilin resistant strains resulted in increasing gellan production up to 6.57 gm/l and the viscosity was about the same as the parent strain. Results also showed that both mutated strains were stable up to three generations.