Whole resting cells vs. cell free extracts of Candida parapsilosis ATCC 7330 for the synthesis of gold nanoparticles

Abstract

The cell free extracts of Candida parapsilosis ATCC 7330 are more efficient than the whole resting cells of the yeast in the synthesis of directly usable gold nanoparticles as revealed by this systematic study. Cell free extracts yielded gold nanoparticles of hydrodynamic diameter (50–200 nm). In this study, the total protein concentration influences the nanofabrication and not only the reductase enzymes as originally thought. Powder X-ray diffraction studies confirm the crystalline nature of the gold nanoparticles. Fourier Transform Infra Red spectroscopy and thermal gravimetric analysis suggests that the biosynthesized gold nanoparticles are capped by peptides/proteins. Dispersion experiments indicate a stable dispersion of gold nanoparticles in pH 12 solutions which is also confirmed by electron microscopic analysis and validated using a surface plasmon resonance assay. The effectiveness of the dispersed nanoparticles for the reduction of 4-nitrophenol using sodium borohydride as a reductant further confirms the formation of functional gold nanoparticles. It is also reported that gold nanoparticles with mean particle diameter of 27 nm are biosynthesized inside the whole cell by transmission electron microscopy analysis. With optimized reaction conditions, maximum gold bioaccumulation with the 24 h culture age of the yeast with cellular uptake of ~1010 gold atoms at the single cell level is achieved but it is not easy to extract the gold nanoparticles from the whole resting cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-016-0268-y) contains supplementary material, which is available to authorized users.

Metallic Nanoparticles Obtained via “Green” Synthesis as a Platform for Biosensor Construction

“…For example, the spectrum of gPdNPs has a peak at 390 nm (Figure 1), which is specific for PdNPs [18,61]. A peak of gAuNPs in the range 525-590 nm is specific for chemically-synthesized AuNPs of different sizes, according to data reported in the literature [8,12,13,19,38,42,43,48] as well as our results [56,62]. The color, size and shape of AuNPs and gAuNPs are dependent on the NPs' synthesis conditions: culture liquid of a 1-day culture incubated for 3 days with HAuCl 4 produces a dark blue solution of small gAuNPs with a peak at 525 nm.…”

“…Many plants [11,12,21,[24][25][26], algae [4], microorganisms [1,3,[7][8][9][10]14,18,23,[27][28][29][30], as well as redox-imbalanced mammalian cells and systems [31] are known to produce nanostructured mineral crystals and metallic NPs with properties similar to chemically-synthesized materials. Biological agents, including polysaccharides, polypeptides, DNA, enzymes secreted by cells [24,[32][33][34][35][36][37][38][39][40][41] and purified enzymes [42,43] are able to reduce noble metal ions to gain metallic NPs. Besides the practical aim of gNPs production, investigations on the green synthesis processes will be useful for elucidating the mechanisms of cells' responses to stress caused by metal ions.…”

“…The exact mechanism of gNP synthesis using biological agents has not been elucidated to date. However, it has been suggested that various biomolecules are involved in this process [24,[38][39][40][41][42][43][44][45][46][47][48]. Capping and stabilizing agents (polysaccharides, polypeptides and other bioorganic compounds) prevent the gNPs from further growth and agglomeration in resulted colloidal solution [45][46][47][48][49][50][51].…”

One‐pot Synthesis of 4‐Aminocyclohexanol Isomers by Combining a Keto Reductase and an Amine Transaminase

“…This makes this reaction more attractive from an economic point of view. Compared to previous attempts, this is the first efficient enzymatic access to produce hydroxyketone 3 , which itself represents a valuable building block for syntheses of compounds against immune disorders, viral and neurological diseases. Compared to our successful monoreduction of 2 (route A), no KRED was identified having activity towards 4 which prompted us to discard route B (Scheme ).…”

Microbial Synthesis of Gold Nanoparticles and Their Applications as Catalysts

“…Krishnan et al have reported that gold nanoparticles biosynthesized using the cell-free extract of yeast Candida parapsilosis ATCC 7330 showed improved dispersion of gold nanoparticles in a pH 12 solution [12]. These dispersed nanoparticles (32 nm) demonstrated their size-dependent catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride (Scheme 1) as a hydride source with an apparent rate constant of 0.138 min À1 and normalized rate constant (k nor ) of 4.18 x 10 7 mol À1 min À1 .…”