title: Influence of biomass and gold salt concentration on nanoparticle synthesis by the tropical marine yeast Yarrowia lipolytica NCIM 3589.
abstract: Cell-associated gold nanoparticles and nanoplates were produced when varying number of Yarrowia lipolytica cells were incubated with different concentrations of chloroauric acid (HAuCl(4)) at pH 4.5. With 10(9)cells ml(-1) and 0.5 or 1.0 mM of the gold salt, the reaction mixtures developed a purple or golden red colour, respectively, and gold nanoparticles were synthesized. Nanoparticles of varying sizes were produced when 10(10)cells ml(-1) were incubated with 0.5, 1.0 or 2.0 mM chloroauric acid salt. With 3.0, 4.0 or 5.0 mM HAuCl(4), nanoplates were also observed. With 10(11)cells ml(-1) nanoparticles were synthesized with almost all the gold salt concentrations. The cell-associated particles were released outside when nanoparticle-loaded cells were incubated at low temperature (20 degrees C) for 48 h. With increasing salt concentrations and a fixed number of cells, the size of the nanoparticles progressively increased. On the other hand, with increasing cell numbers and a constant gold salt concentration, the size of nanoparticles decreased. These results indicate that by varying the number of cells and the gold salt concentration, a variety of nanoparticles and nanoplates can be synthesized. Fourier transform infrared (FTIR) spectroscopy revealed the possible involvement of carboxyl, hydroxyl and amide groups on the cell surfaces in nanoparticle synthesis.
authors.affiliation: Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411007, India.
authors.forename: P S
authors.initials: PS
authors.lastname: Pimprikar
authors.forename: S S
authors.initials: SS
authors.lastname: Joshi
authors.forename: A R
authors.initials: AR
authors.lastname: Kumar
authors.forename: S S
authors.initials: SS
authors.lastname: Zinjarde
authors.forename: S K
authors.initials: SK
authors.lastname: Kulkarni
mesh_terms: D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D018533:Biomass; D002473:Cell Wall / Q000378:metabolism; D006046:Gold / Q000494:pharmacology*; D053758:Nanoparticles / Q000737:chemistry / Q000382:microbiology*; D010316:Particle Size; D012623:Seawater / Q000382:microbiology*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014329:Tropical Climate; D014961:X-Ray Diffraction; D025062:Yarrowia / Q000166:cytology / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure
chemical_list: D006046:Gold