An experimental soil (20 cm depth) was collected from Jodhpur, India (26°18′N 73°01′E), then air dried and sieved through 2 mm mesh. The soil was classified as loamy sand. Organic carbon was estimated by following the method of Walkley and Black [14]. Nitrogen, phosphorous and potassium were analyzed by Jackson [15]. In addition, pH and electrical conductivity were also measured. The fungi was isolated from rhizosphere soil by initial plating on Martin Rose Bengal Agar medium (Hi-Media, India, pH 7.2) followed by serial dilutions over potato dextrose agar medium supplemented
with chloramphenicol (Sigma–Aldrich, St. Louis, USA) at a concentration of 10 μg mL−1. Isolated fungi was identified up to molecular level by partial sequencing of 18S and 28S rRNA and complete sequence of internal transcribed sequence 1 (ITS-1), Natural Product Library mouse ITS-2 and 5.8S rRNA. The sequence was compared with gene library data available on National Centre of Biotechnology Information (www.ncbi.nlm.nih.gov) using nucleotide blast algorithms, to identify isolated fungal strain using bioinformatics tool ‘blastn’. To synthesize TiO2 nanoparticles,
A. flavus TFR 7 was developed in broth medium (pH 5.8) supplemented Ivacaftor cost with of 0.3% malt extract, 1% sucrose, 0.3% yeast extract, and 0.5% peptone. The culture was kept on shaker at 150 rpm at 28 °C for 72 h to develop fungal ball of mycelia. These mycelia were separated out by filtration Whatman filter paper no. 1 (Whatman, UK) followed by triple washing with deionized water. Reaped mycelia (10 g fresh biomass) were re-suspended in 100 mL deionized water and incubated for 48 h at 28 °C under the same shaking condition as above. The obtained cell Ureohydrolase free filtrate containing extracellular enzymes was used for synthesis of TiO2 NPs, in which precursor salt (Bulk TiO2) was mixed at a concentration of 10−3 M and incubated for 36 h
at 150 rpm and 28 °C to yield fine monodisperse TiO2 NPs, Synthesized nano-crystals were characterized morphologically by transmission electron microscopy (TEM; JEOL JEM-2100F) including high resolution (HR)–TEM mode for crystal phase confirmation, and energy dispersive X-ray spectroscopy (EDS; Thermo Noran equipped with TEM) for surface elemental analyses. Since particles were dispersed in water, hydrodynamic diameter was analyzed using dynamic light scattering (DLS; Beckman DelsaNano C, USA). The certified seed (obtained from institutional seed house) were surface-sterilized using 10% sodium hypochlorite solution followed by triple wash with deionized water. After that, five seeds were sown at 3 cm depth in each pot. The pots were placed in a greenhouse with 16 h photoperiod and 30/20 °C day–night temperature, 60% relative humidity and 360 μmol m−2 s−1 photoactive radiation intensity. After 10 days of germination, seedlings were thinned to three per pot. The pots were completely randomized and re-positioned weekly to minimize uneven environmental effects.