title: Bioproduction of D-Tagatose from D-Galactose Using Phosphoglucose Isomerase from Pseudomonas aeruginosa PAO1.
abstract: Pseudomonas aeruginosa PAO1 phosphoglucose isomerase was purified as an active soluble form by a single-step purification using Ni-NTA chromatography that showed homogeneity on SDS-PAGE with molecular mass ∼62 kDa. The optimum temperature and pH for the maximum isomerization activity with D-galactose were 60 °C and 7.0, respectively. Generally, sugar phosphate isomerases show metal-independent activity but PA-PGI exhibited metal-dependent isomerization activity with aldosugars and optimally catalyzed the D-galactose isomerization in the presence of 1.0 mM MnCl2. The apparent Km and Vmax for D-galactose under standardized conditions were calculated to be 1029 mM (±31.30 with S.E.) and 5.95 U/mg (±0.9 with S.E.), respectively. Equilibrium reached after 180 min with production of 567.51 μM D-tagatose from 1000 mM of D-galactose. Though, the bioconversion ratio is low but it can be increased by immobilization and enzyme engineering. Although various L-arabinose isomerases have been characterized for bioproduction of D-tagatose, P. aeruginosa glucose phosphate isomerase is distinguished from the other L-arabinose isomerases by its optimal temperature (60 °C) for D-tagatose production being mesophilic bacteria, making it an alternate choice for bulk production.
authors.affiliation: P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, 388 421, Gujarat, India.
authors.forename: Manisha J
authors.initials: MJ
authors.lastname: Patel
authors.affiliation: P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, 388 421, Gujarat, India.
authors.forename: Arti T
authors.initials: AT
authors.lastname: Patel
authors.affiliation: P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, 388 421, Gujarat, India.
authors.forename: Rekha
authors.initials: R
authors.lastname: Akhani
authors.affiliation: P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, 388 421, Gujarat, India.
authors.forename: Samir
authors.initials: S
authors.lastname: Dedania
authors.affiliation: P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, 388 421, Gujarat, India. darshanpatel.bt@charusat.ac.in.
authors.forename: Darshan H
authors.initials: DH
authors.lastname: Patel
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence / Q000235:genetics; D001089:Arabinose / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005690:Galactose / Q000737:chemistry; D005956:Glucose-6-Phosphate Isomerase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D006601:Hexoses / Q000096:biosynthesis* / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D013696:Temperature
chemical_list: D006601:Hexoses; D001089:Arabinose; D019747:Aldose-Ketose Isomerases; C019715:L-arabinose isomerase; D005956:Glucose-6-Phosphate Isomerase; C030192:tagatose; D005690:Galactose
keywords: D-Galactose; D-Tagatose; Phosphoglucose isomerase; Pseudomonas aeruginosa PAO1