Biosynthesis of titanium dioxide nanoparticles using probiotic bacterial strain, Lactobacillus rhamnosus, and evaluate of their biocompatibility and antifungal activity

Abstract

The main goal of the current study is to biosynthesize titanium dioxide nanoparticles (TiO2-NPs) using green approach to biocontrol of different fungal strains isolated from historical Description of Egypt book. Nineteen fungal strains were isolated from deteriorated parts and identified by the traditional and molecular methods as Aspergillus flavus (8-isolates), Aspergillus versicolor (2-isolates), Aspergillus ustus (4-isolates), Aspergillus chinensis (2-isolates), Penicillium citrinum (2-isolates), and Penicillium chrysogenum (1-isolate). These fungal strains showed high cellulase, amylase, pectinase, and gelatinase activities which have a significant role in biodeterioration. The biomass filtrate of probiotic strain, Lactobacillus rhamnosus, was used to fabricate TiO2-NPs which characterized by UV-Vis, FT-IR, XRD, TEM, SEM, EDX, DLS, and zeta potential. The obtained data showed the successful formation of spherical and anatase phase NPs with sizes of 3–7 nm and zeta potential values of – 19.9 and – 36.8 mV. The main components of as-formed nanomaterial were Ti and O with weight percentages of 55.91 and 46.25, respectively. The biocompatibility of synthesized TiO2-NPs was investigated toward two normal cell lines, WI38 and HFB4, which reveal the low toxicity at high concentrations (IC50 > 300 μg mL–1). Therefore, concentrations ≤ 300 μg mL–1 were used to biocontrol of isolated fungi. Data showed the promising activity of various concentrations (300, 200, and 100 μg mL–1) of TiO2-NPs to inhibit the growth of fungal strains with varied inhibition zones and dose-dependent manner. This study exhibited the efficacy of probiotic bacterial strains in the synthesis of TiO2-NPs that can be used to preserve historical books from fungal deterioration. Graphical Abstract

A novel functionalized CuTi hybrid nanocomposites: facile one-pot mycosynthesis, characterization, antimicrobial, antibiofilm, antifouling and wastewater disinfection performance

“…Meanwhile, some studies presented a spectrum in which the absorption peaks of around 380 and 400 nm correspond to TiNPs anatase phase, with the cutoff wavelength at 379 nm [ 70 , 71 ]. Notably [ 45 ], found that SPR of bacterially synthesized TiNPs at 360 nm. whereas [ 72 ], detected it at 380 nm, which were synthesized by Bacillus mycoids .…”

“…whereas [ 72 ], detected it at 380 nm, which were synthesized by Bacillus mycoids . Generally, the maximum absorption peak related to TiNPs was observed in the range of 300–400 nm [ 45 ].…”

“…For detecting intracellular synthesis of NPs-NCs, a yeast lawn of 0.5 McFarland (≈ 10 8 CFU/ml), taken from a previous freshly prepared culture, was inoculated in 250 mL Erlenmeyer flasks containing 70 mL of (MRS broth) (Oxoid) supplemented with 1.5 mM of (i.e., Cu (NO 3 ) 2 , 1.5 mM of C 12 H 28 O 4 Ti and both. The precursors’ concentrations were selected based on the minimal inhibitory concentration (MIC) test (data not shown) [ 45 ]. However, the extracellular synthesis approach was monitored by inoculating cell-free filtrate of fresh culture (100 mL) with the exact concentrations of metals’ precursors either solely or mixed.…”

“…Concurrently, control flasks, namely, MRS broth containing yeast culture without metal precursors and MRS broth containing metal precursors without yeast cultures, were run in parallel with the test flasks. The primary sign of NPs-NCs fabrication was monitored visually throughout the incubation period via color changes in media and biomass from pale yellow to white, dark brown and whitish brown; indicating a successful formation of TiNPs, CuNPs and CuTiNCs, respectively [ 44 , 45 ]. After complete incubation, the precipitates containing NPs-NCs either from intracellular or extracellular test flasks were harvested by centrifugation at 12,000×g for 20 min.…”

“…The optical properties of the NPs-NCs were first determined at room temperature using UV– Visible spectrophotometer, (Labomed model-double beam) within a wavelength range of 200–800 nm to detect Surface Plasmon Resonance (SPR). For the morphological properties and size, transmission electron microscopy (TEM) [JEOL JEM-1230-Japan], operated at 200 kV and Scanning electron microscopy (SEM) (JEOL JSM-6360LA) were employed [ 45 ]. For analyzing the physical configuration, phase identification and crystallinity of NPs-NCs, X-ray diffractometer (Shimadzu 7000, USA) operated with Cu Kα radiation (λ = 0.15406 nm), generated at 30 kV and 30 mA with a scan rate of 2°/min for 2θ values across a wide range of Bragg angles 10° ≤ 2θ ≤ 100, was employed in X-ray diffraction (XRD) analysis.…”