Synthesis and characterization of titanium dioxide nanoparticles from Bacillus subtilis MTCC 8322 and its application for the removal of methylene blue and orange G dyes under UV light and visible light

Chandani Rathore; Virendra Kumar Yadav; Abdelfattah Amari; Abhishek Meena; Titus Chinedu Egbosiuba; Rakesh Kumar Verma; Noureddine Mahdhi; Nisha Choudhary; Dipak Kumar Sahoo; Rajendra Singh Chundawat; Ashish Patel

doi:10.3389/fbioe.2023.1323249

Synthesis and characterization of titanium dioxide nanoparticles from Bacillus subtilis MTCC 8322 and its application for the removal of methylene blue and orange G dyes under UV light and visible light

Front Bioeng Biotechnol. 2024 Jan 8:11:1323249. doi: 10.3389/fbioe.2023.1323249. eCollection 2023.

Affiliations

¹ Department of Biosciences, School of Liberal Arts and Sciences, Mody University of Science and Technology, Sikar, Rajasthan, India.
² Department of Life Sciences, Hemchandracharya North Gujarat University, Patan, Gujarat, India.
³ Department of Chemical Engineering, College of Engineering, King Khalid University, Abha, Saudi Arabia.
⁴ Department of Physics and Semiconductor Science, Dongguk University, Seoul, Republic of Korea.
⁵ Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, United States.
⁶ Laboratory Materials Organizations and Properties, Tunis El Manar University, Tunis, Tunisia.
⁷ Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.

Abstract

Over the last decade there has been a huge increase in the green synthesis of nanoparticles. Moreover, there is a continuous increase in harnessing the potential of microorganisms for the development of efficient and biocompatible nanoparticles around the globe. In the present research work, investigators have synthesized TiO₂ NPs by harnessing the potential of Bacillus subtilis MTCC 8322 (Gram-positive) bacteria. The formation and confirmation of the TiO₂ NPs synthesized by bacteria were carried out by using UV-Vis spectroscopy, Fourier transforms infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX/EDS). The size of the synthesized TiO₂ NPs was 80-120 nm which was spherical to irregular in shape as revealed by SEM. FTIR showed the characteristic bands of Ti-O in the range of 400-550 cm^-1 and 924 cm^-1 while the band at 2930 cm^-1 confirmed the association of bacterial biomolecules with the synthesized TiO₂ NPs. XRD showed two major peaks; 27.5° (rutile phase) and 45.6° (anatase phase) for the synthesized TiO₂ NPs. Finally, the potential of the synthesized TiO₂ NPs was assessed as an antibacterial agent and photocatalyst. The remediation of Methylene blue (MB) and Orange G (OG) dyes was carried out under UV- light and visible light for a contact time of 150-240 min respectively. The removal efficiency for 100 ppm MB dye was 25.75% and for OG dye was 72.24% under UV light, while in visible light, the maximum removal percentage for MB and OG dye was 98.85% and 80.43% respectively at 90 min. Moreover, a kinetic study and adsorption isotherm study were carried out for the removal of both dyes, where the pseudo-first-order for MB dye is 263.269 and 475554.176 mg/g for OG dye. The pseudo-second-order kinetics for MB and OG dye were 188.679 and 1666.667 mg/g respectively. In addition to this, the antibacterial activity of TiO₂ NPs was assessed against Bacillus subtilis MTCC 8322 (Gram-positive) and Escherichia coli MTCC 8933 (Gram-negative) where the maximum zone of inhibition in Bacillus subtilis MTCC 8322 was about 12 mm, and for E. coli 16 mm.

Keywords: biotransformation; nanocatalyst; photocatalytic degradation; reactive oxygen species; wastewater; zone of inhibition.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Deanship of Scientific Research at King Khalid University under Grant number RGP.2/34/44.