Production of Some Biodegradable Polymers by Some Bacterial Isolates

Abstract

Several bacterial isolates were isolated from Dakahlia and Damitta Governorates. The isolates were purified, identified and tested for PHB production. The tested isolates were 17 isolates of Azotobacter chroococcum, 8 isolates of Azospirillum lipoferum, 22 isolates of Alcaligenes eutrophus, 3 isolates of A. latus, 3 isolates of Bacillus subtilis, 2 isolates of B. cereus, 5 isolates of B. megaterium, 2 isolates of B. coagulans, 3 isolates of B. polymexa, 4 isolates of B. thuringiensis, 2 isolates of Pseudomonas fluorescens, 2 isolates of P. putida, 2 isolates of P. alcaligenes, 2 isolates of P. aeruginosa, 4 isolates of Rhizobium leguminosarim, 2 isolates of R. meliloti, one isolate of R. japonicum and 12 isolates of Streptomyces albus. Also, the occurrence of alginate in different isolates of Azotobacter and Pseudomonas were investigated.All isolated strains proved to be PHB producers. The amount of PHB produced by Bacillus isolates varied from 0.02 to 0.16 g/l, while by Azospirillum isolates the PHB amounts ranged from 0.12 to 0.58 g/l. Using Rhizobium isolates, the highest amount of PHB (0.36 g/l) was produced by R. leguminasarim No 3 , while the lowest amount (0.06 g/l) was obtained by R. leguminosarim No 2. Usig two media, Alcaligenus eutrophus No. 20, seemed to be the most active PHB producer among all Alcaligenes isolates (0.52 g/l). By Pseudomonas isolates, Pseudomonas fluorescens No. 2 produced 0.30 g/L of PHB while P. aeruginosa No. 2 produced 0.10 g/L. Generally the isolate of Azotobacter chroococcum No. 16 showed the highest values. The cell dry weight, PHB concentration and the yield of PHB were 2.28 g/l, 0.78 g/l, 34.21%, respectively. And the highest amount of alginate concentration (g/l) was 0.44 by Azotobacter chroococcum No. 14.

Biosynthesis of Poly-ß-Hydroxybutyrate (PHB) from Different Bacterial Strains Grown on Alternative Cheap Carbon Sources

“…Three species of the genus Azotobacter sp. have commonly appeared in the literature on the production of PHB, including A. chroococcum [19,28,41,42,49], A. vinelandii [50][51][52][53], and A. beijerinckii [54][55][56]; however, only one used A. salinestris for PHB production [57] before this study. Isolate No.…”

“…Multiple previous studies [19,41] produced PHB from A. chroococcum in amounts ranging from 2.0 to 3.0 g/L, higher than in the current study; however, [10] produced only about 1.0 g/L from A. vinelandii, lower than this study. In [42], the production of PHB was studied using the shaking culture method with A. chroococcum resulting in a PHB% of 46.80%. On the other hand, PHB was produced from all isolates grown on medium (C) in the present study (Table 1).…”