ALGINATE PRODUCTION USING A NATIVE PSEUDOMONAS SP. ISOLATED FROM SOIL

Background and Aim:Alginates are polysaccharides that are produced by brown seaweeds, some red algae and Gram negative bacterial genera. These are used in various industries including foods, cosmetics, pharmaceuticals, drug delivery, medicine and tissue engineering. The purpose of this study was isolation of native alginate producer strains from soil in Ahvaz.Methods:Soil samples were harvested from plant decomposing region. Ten g of sample was added to 90 ml of physiological saline and incubated at 27 °C with continuous shaking. Following precipitation of suspended particles,10 μl of supernatant was cultured on Mueller Hinton agar medium and the appeared colonies were screened on Cetrimide agar for Pseudomonas spp. isolation. Nitrogen fixation ability of isolates were investigated through Döbereiner assay. Pseudomonas spp. were identified by biochemical tests. Alginate was extracted through sequential stages such as centrifugation, sedimentation by ethanol and drying in vacuum and confirmed through Carbazole analysis assay with borate. The quantitative assay of produced alginate was done through absorbance measurement at 530 nm and comparison with standard alginate solution absorbance.Results:The selected Pseudomonas sp. was able to produce alginate of 7.40 w/w with yield and a 0.926 mg/ml concentration in Nutrient broth medium while in the modified salt medium (MMSM) with 5% Vinasse, the yield of alginate production was 50.485 w/w with 1.09 mg/ml concentration.Conclusion:The results revealed that vinasse as a cheap and available substrate can be used for alginate production by isolated Pseudomonas sp. and further studies are needed to develop this process for optimized alginate production.

Keywords:

Alginate , biopolymer , Pseudomonas spp. , Carbazole assay , Vinasse