title: Phospholipid fatty acids as physiological indicators of Paracoccus denitrificans encapsulated in silica sol-gel hydrogels.
abstract: The phospholipid fatty acid (PLFA) content was determined in samples of Paracoccus denitrificans encapsulated in silica hydrogel films prepared from prepolymerized tetramethoxysilane (TMOS). Immediately after encapsulation the total PLFA concentration was linearly proportional to the optical density (600 nm) of the input microbial suspension (R2 = 0.99). After 7 days this relationship remained linear, but with significantly decreased slope, indicating a higher extinction of bacteria in suspensions of input concentration 108 cells/mL and higher. trans-Fatty acids, indicators of cytoplasmatic membrane disturbances, were below the detection limit. The cy/pre ratio (i.e., ratio of cyclopropylated fatty acids (cy17:0 + cy19:0) to their metabolic precursors (16:1ω7 + 18:1ω7)), an indicator of the transition of the culture to a stationary growth-phase, decreased depending on co-immobilization of nutrients in the order phosphate buffer > mineral medium > Luria Broth rich medium. The ratio, too, was logarithmically proportional to cell concentration. These results confirm the applicability of total PLFA as an indicator for the determination of living biomass and cy/pre ratio for determination of nutrient limitation of microorganisms encapsulated in sol-gel matrices. This may be of interest for monitoring of sol-gel encapsulated bacteria proposed as optical recognition elements in biosensor construction, as well as other biotechnological applications.
authors.affiliation: Faculty of Environment, Jan Evangelista Purkyně University in Ústí nad Labem, KrálovaVýšina 3132/7, Ústí nad Labem 400 96, Czech Republic. josef.trogl@ujep.cz.
authors.forename: Josef
authors.initials: J
authors.lastname: Trögl
authors.affiliation: Faculty of Environment, Jan Evangelista Purkyně University in Ústí nad Labem, KrálovaVýšina 3132/7, Ústí nad Labem 400 96, Czech Republic. IvanaJirkova@seznam.cz.
authors.forename: Ivana
authors.initials: I
authors.lastname: Jirková
authors.affiliation: Faculty of Environment, Jan Evangelista Purkyně University in Ústí nad Labem, KrálovaVýšina 3132/7, Ústí nad Labem 400 96, Czech Republic. pavel.kuran@ujep.cz.
authors.forename: Pavel
authors.initials: P
authors.lastname: Kuráň
authors.affiliation: Faculty of Food Technology, Kazan National Research Technological University, Karl-Marx-Str. 8, Kazan 420 015, Russia. mira-axmetshina@mail.ru.
authors.forename: Elmira
authors.initials: E
authors.lastname: Akhmetshina
authors.affiliation: Faculty of Environment, Jan Evangelista Purkyně University in Ústí nad Labem, KrálovaVýšina 3132/7, Ústí nad Labem 400 96, Czech Republic. tatjana.brovdyova@ujep.cz.
authors.forename: Taťjána
authors.initials: T
authors.lastname: Brovdyová
authors.affiliation: Faculty of Food Technology, Kazan National Research Technological University, Karl-Marx-Str. 8, Kazan 420 015, Russia. asirotkin@mail333.com.
authors.forename: Alexander
authors.initials: A
authors.lastname: Sirotkin
authors.affiliation: Faculty of Food Technology, Kazan National Research Technological University, Karl-Marx-Str. 8, Kazan 420 015, Russia. tvkirilina@gmail.com.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kirilina
mesh_terms: D015374:Biosensing Techniques; D005227:Fatty Acids / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D010231:Paracoccus denitrificans / Q000378:metabolism*; D010743:Phospholipids / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D020100:Hydrogels; D010743:Phospholipids