title: Polyglutamic acid (PGA) production by Bacillus sp. SAB-26: application of Plackett-Burman experimental design to evaluate culture requirements.
abstract: A locally isolated thermostable Bacillus strain producing polyglutamic acid (PGA) was characterized and identified based on 16S rRNA sequencing. Phylogenetic analysis revealed its closeness to Bacillus licheniformis. To evaluate the effect of different culture conditions on the production of PGA, Plackett-Burman factorial design was carried out. Fifteen variables were examined for their significance on PGA production. Among those variables, K(2)HPO(4), KH(2)PO(4), (NH(4))(2)SO(4) and casein hydrolysate were found to be the most significant variables that encourage PGA production. A correlation between cellular growth, PGA and the produced traces of polysaccharides was illustrated. An inverse relationship practice between cell dry weights and the produced PGA was demonstrated. On the other hand, a direct proportional relation was shown between polysaccharides on one side and cell dry weight and produced PGA on the other. The pre-optimized medium, based on statistical analysis, showed a production of 33.5 g/l PGA, which is more than three times the basal medium.
authors.affiliation: Bioprocess Development Department, Genetic Engineering and Biotechnology Research Institute, Mubarak City for Scientific Research and Technology Applications, New Burg El-Arab City, Alexandria, Egypt.
authors.forename: Nadia A
authors.initials: NA
authors.lastname: Soliman
authors.forename: Mahmoud M
authors.initials: MM
authors.lastname: Berekaa
authors.forename: Yasser R
authors.initials: YR
authors.lastname: Abdel-Fattah
mesh_terms: D001407:Bacillus / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D018533:Biomass; D003470:Culture Media; D010802:Phylogeny; D011099:Polyglutamic Acid / Q000096:biosynthesis*; D012107:Research Design
chemical_list: D003470:Culture Media; D011099:Polyglutamic Acid