Biosynthesis of metal and oxide nanoparticles using Lactobacilli from yoghurt and probiotic spore tablets Anal K. Jha1 and K. Prasad2
Department of Chemistry, T.M. Bhagalpur University, Bhagalpur, India Department of Physics, T.M. Bhagalpur University, Bhagalpur, India
Green, low-cost, and reproducible Lactobacillus-mediated biosynthesis of metal and oxide nanoparticles are reported. Silver and titanium dioxide nanoparticles are synthesized using Lactobacillus sp. procured from yoghurt and probiotic tablets. The synthesis is performed akin to room temperature in the laboratory ambience. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of metallic and oxide nanoparticles. Individual nanoparticles having the dimensions of 10–25 nm (n-Ag) and 10–70 nm (n-TiO2) are found. The mechanism involved for the synthesis of metallic and oxide nanoparticles has also been discussed.
Received 31 September 2009 Revised 28 November 2009 Accepted 24 December 2009
Keywords: Biosynthesis · Green approach · Nanobiotechnology · Nanomaterial · Nanoparticle
Nature by dint of its diversity provides exponential possibilities in terms of endearing adaptability of its constituent cohorts. Bacteria make such an exciting category of microorganisms having naturally bestowed property of reducing/oxidizing metal ions into metallic/oxide nanoparticles thereby functioning as “mini” nanofactories [1, 2]. It is indeed their chemical constitutions (or metabolic status) which provides them strength to withstand even in environmentally extreme habitats. The non-pathogenic, gram positive, and mesophilic facultative anaerobe Lactobacillus, commonly used for curdling of milk, forms part of the beneficial community of microbes present in the human intestinal tract. Recent research into the interaction be-
Correspondence: Dr. K. Prasad, University Department of Physics, T.M. Bhagalpur University, Bhagalpur 812007, India E-mail: email@example.com Fax: +91-641-2501699 Abbreviations: GSH, glutathione; Hpk, histidine protein kinase; LAB, lactic acid bacteria; ROS, reactive oxygen species; RR, response regulator; SAED, selected area electron diffraction; TEM, transmission electron microscope; XRD, X-ray diffraction
tween inorganic entities and biologic systems has emphasized its prodigious applications for the production of nanomaterials with interesting technologic properties [1–11]. There are several procedures to synthesize metallic/oxide nanoparticle, each having its own advantages and/or disadvantages. The development of ecologically friendly, “green” synthesis protocols is in line with the recent RoHS and WEEE legislation stipulated by the EU. To meet the requirement there is a need to develop an eco-friendly approach for nanomaterials synthesis that should not use toxic chemicals in the synthesis protocol. It is well known that many organisms, can produce inorganic materials either intra- or extracellularly. The recent discovery of the biosynthesis of metal and oxide nanoparticles points towards new biotechnological methods in materials science. Earlier, silver nanoparticle was synthesized, using of Lactobacilli procured from buttermilk, by Nair and Pradeep . Recently, using this procedure with slight modifications, we had been able to synthesize Cd , Ti , Ag , TiO2 , and Cu2O  nanoparticles. In our most recent efforts, we had employed L. sporogens finding its widespread functional prodigality in order to synthesize ZnO , Sb2O3 , BaTiO3 , and CdS  nanoparticles. In the present effort, we have taken use of both
© 2010 Wiley–VCH Verlag GmbH & Co. KGaA, Weinheim
Biotechnol. J. 2010, 5
types of bacteria, one procured from the yoghurt and other grown from the readily available...