Effect of Some Physical Mutagens on Pseudomonas aeruginosa H3 in Alginate Production

Abstract

Effect of physical mutagens on the ability of Pseudomonas aeruginosa H3 in alginate production was performed by subjection of the cell suspension of P. aeruginosa H3 to different doses of UV radiation (2, 4, 6, 8 and 10 J/m2) and LASER for (30, 60, 90 and 120 sec.), then cell suspension was spread on LB agar plates and incubated at 37 ˚C for 24hrs. After that, random selection of thirty colonies that arose from the cells subjection to the effect of different doses of UV radiation and laser were made (90% of the suspended cells were killed and were tested for their alginate production). Results showed that the mutagenesis by UV radiation caused an increase in the ability of P. aeruginosa H3 in alginate production. Over-producer mutant, H3R1, was obtained from this treatment. The productivity of the alginate from this mutant was 170mg/l in comparison with the productivity of wild type (70mg/l). On the other hand, results also showed that mutagenesis using LASER radiation caused an increase in the ability of P. aeruginosa H3 in alginate production. Over-producer mutant, H3R42, was obtained from this treatment characterized by its high ability in alginate production (130mg/l) in comparison with the productivity of wild type (70mg/l). Results of Fourier Transform-Infra Red (FT-IR) for alginate produced by the wild type of P. aeruginosa H3 and over-producer mutants H3R1 and H3R42 at a wide range of wave lengths absorbance (400-4000) cm-1 showed that there were no any structural differences in the chemical structure of alginate produced by them on the basis of infra-red light absorption by different functional groups of alginate