title: Molecular identification of potential denitrifying bacteria and use of D-optimal mixture experimental design for the optimization of denitrification process.
abstract: Three bacterial strains (TE1, TD3 and FB2) were isolated from date palm (degla), pistachio and barley. The presence of nitrate reductase (narG) and nitrite reductase (nirS and nirK) genes in the selected strains was detected by PCR technique. Molecular identification based on 16S rDNA sequencing method was applied to identify positive strains. In addition, the D-optimal mixture experimental design was used to optimize the optimal formulation of probiotic bacteria for denitrification process. Strains harboring denitrification genes were identified as: TE1, Agrococcus sp LN828197; TD3, Cronobacter sakazakii LN828198 and FB2, Pedicoccus pentosaceus LN828199. PCR results revealed that all strains carried the nirS gene. However only C. sakazakii LN828198 and Agrococcus sp LN828197 harbored the nirK and the narG genes respectively. Moreover, the studied bacteria were able to form biofilm on abiotic surfaces with different degree. Process optimization showed that the most significant reduction of nitrate was 100% with 14.98% of COD consumption and 5.57 mg/l nitrite accumulation. Meanwhile, the response values were optimized and showed that the most optimal combination was 78.79% of C. sakazakii LN828198 (curve value), 21.21% of P. pentosaceus LN828199 (curve value) and absence (0%) of Agrococcus sp LN828197 (curve value).
authors.affiliation: Laboratory of Analysis, Treatment and Valorization of Environmental Pollutants and Products, Faculty of Pharmacy, Monastir University, Tunisia.
authors.forename: Fadia
authors.initials: F
authors.lastname: Ben Taheur
authors.affiliation: Laboratory of Analysis, Treatment and Valorization of Environmental Pollutants and Products, Faculty of Pharmacy, Monastir University, Tunisia.
authors.forename: Kais
authors.initials: K
authors.lastname: Fdhila
authors.affiliation: Laboratory of Analysis, Treatment and Valorization of Environmental Pollutants and Products, Faculty of Pharmacy, Monastir University, Tunisia.
authors.forename: Hamouda
authors.initials: H
authors.lastname: Elabed
authors.affiliation: Laboratory of Analysis, Treatment and Valorization of Environmental Pollutants and Products, Faculty of Pharmacy, Monastir University, Tunisia.
authors.forename: Amel
authors.initials: A
authors.lastname: Bouguerra
authors.affiliation: College of Applied Medical Sciences, Medical Laboratory Department, Yanbu el Bahr, Taibah University, Al Madinah Al Monawarah, Saudi Arabia. Electronic address: bochrak@yahoo.fr.
authors.forename: Bochra
authors.initials: B
authors.lastname: Kouidhi
authors.affiliation: Laboratory of Analysis, Treatment and Valorization of Environmental Pollutants and Products, Faculty of Pharmacy, Monastir University, Tunisia.
authors.forename: Amina
authors.initials: A
authors.lastname: Bakhrouf
authors.affiliation: College of Sciences, Biology Department, Yanbu el Bahr, Taibah University, Al Madinah Al Monawarah, Saudi Arabia.
authors.forename: Kamel
authors.initials: K
authors.lastname: Chaieb
mesh_terms: D001419:Bacteria / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms; D058440:Denitrification; D001467:Hordeum / Q000382:microbiology*; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009572:Nitrite Reductases / Q000235:genetics / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D065749:Phoeniceae / Q000382:microbiology*; D010802:Phylogeny; D027927:Pistacia / Q000382:microbiology*; D012107:Research Design
chemical_list: D001426:Bacterial Proteins; D009566:Nitrates; D009573:Nitrites; D009572:Nitrite Reductases; D050901:Nitrate Reductase
keywords: 16S rDNA; Denitrification gene; Mixture design; Molecular identification; Optimization; Probiotic bacteria