title: Optimization, kinetics and antioxidant activity of exopolysaccharide produced from rhizosphere isolate, Pseudomonas fluorescens CrN6.
abstract: Pseudomonas fluorescens, isolated from rhizosphere soil, was exploited for the production of exopolysaccharide (EPS). A medium was constituted to enhance the yield of EPS. This study involved an agro waste as carbon substrate, rice bran, a replacement of glucose. Plackett-Burman statistical design was applied to evaluate the selected sixteen components from which, rice bran, peptone, NaCl and MnCl2 were found to be effective and significant on the fermentation process. To study the concentration of each component, central composite design was carried out and response surface plots indicated that the following concentrations significantly enhanced the production - rice bran 5.02%, peptone 0.35%, NaCl 0.51%, MnCl2 0.074%. Kinetic modeling was also performed to simulate the process parameters. Logistic model for microbial growth and Luedeking-Piret equation for product formation and substrate utilization were found to fit the experiment. The present investigation resulted in a maximum yield of 4.62g of EPS/L at 48h. High DPPH scavenging ability was a positive indication to use EPS as an antioxidant. The extracted polysaccharide could thus be ecofriendly due to its biodegradability and nontoxicity, and subjected to various industrial and pharmaceutical applications.
authors.affiliation: Bioprocess Laboratory, Department of Chemical Engineering, Annamalai University, Annamalai Nagar 608002, Tamilnadu, India. Electronic address: siraj.razack@gmail.com.
authors.forename: Abdul Razack
authors.initials: AR
authors.lastname: Sirajunnisa
authors.affiliation: Bioprocess Laboratory, Department of Chemical Engineering, Annamalai University, Annamalai Nagar 608002, Tamilnadu, India.
authors.forename: Velayutham
authors.initials: V
authors.lastname: Vijayagopal
authors.affiliation: Bioprocess Laboratory, Department of Chemical Engineering, Annamalai University, Annamalai Nagar 608002, Tamilnadu, India.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Sivaprakash
authors.affiliation: Bioprocess Laboratory, Department of Chemical Engineering, Annamalai University, Annamalai Nagar 608002, Tamilnadu, India.
authors.forename: Thangavelu
authors.initials: T
authors.lastname: Viruthagiri
authors.affiliation: Bioprocess Laboratory, Department of Chemical Engineering, Annamalai University, Annamalai Nagar 608002, Tamilnadu, India.
authors.forename: Duraiarasan
authors.initials: D
authors.lastname: Surendhiran
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000737:chemistry; D007700:Kinetics; D010802:Phylogeny; D010851:Picrates / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry; D011551:Pseudomonas fluorescens / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D058441:Rhizosphere
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; D011135:Polysaccharides, Bacterial; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Antioxidant activity; Exopolysaccharide; FTIR spectrometry; Kinetic models; Pseudomonas fluorescens; Response surface methodology; Rice bran