Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Globally, waste electrical and electronic equipment is one of the fastest-growing waste sectors. Mobile phones constitute the major portion of the telecommunication e-waste category. Over the years, waste mobile phones were considered as a potential source of secondary metals. This study aims to determine the physical and chemical composition of the discarded mobile phones and to evaluate its recovery potential. The printed circuit boards from the discarded (waste) mobile phones (MPCB) were collected and samples of different sizes 3 × 3 cm, 2 mm, 1 mm, 500 µm, and 150 µm were obtained after milling and sieving. Elemental composition revealed the presence of base metals, Cu, Zn, Fe, Ni, and Pb, in higher quantities with a significant amount of precious metals Au and Ag. Amount of base metals present in different MPCB size fractions was found in the order 3 × 3 cm > 2 mm > 1 mm > 500 µm >150 µm. The amount of precious metals like Ag and Au was found to be higher in large-sized MPCB fractions. FTIR studies declared the presence of polymers like ABS, PC, and HIPs in MPCB samples. TCLP tests for toxic metals revealed that MPCBs contained high concentrations of cadmium, lead, and mercury highlighting their hazardous potential. The ultimate analysis revealed that NMF has a GCV of 12.34 MJ/kg and a volatile content of 42.25%, which can be a potential source of energy that can be recovered through the gasification or pyrolysis process. Overall, the comprehensive characterization of waste MPCBs will systematically provide a better understanding of e-waste recycling processes for beneficiation purpose and sustainable resource utilization. Implications: A comprehensive characterization of waste mobile phone printed circuit boards for its elemental composition was performed. Mechanical treatment steps before MPCBs processing increased the exposure of metals resulting in a higher concentration of metals in acid-digested samples. The elemental analysis of MPCBs revealed that MPCBs possessed significant quantities of base and precious metals. The amount of precious metals like Ag and Au was also found in higher ranges in large-sized MPCB fractions, which elucidated fact to be considered in the pre-treatment process for metal recoveries. The high content of base and precious metals in waste mobile phones displayed their economic potential in the market. This new source may compensate for the escalating global demand for gold and silver. Results from the study indicated that MPCBs can serve as an excellent secondary source for various metals and as an efficient alternative fuel. © 2021 A&WMA.

World University root node

Department of Biotechnology

School of Bio Sciences and Technology

Vellore Campus

Journal of the Air and Waste Management Association

Characterization of end-of-life mobile phone printed circuit boards for its elemental composition and beneficiation analysis

VIT Unitversity

Environmental Chemistry Letters

Enhanced bioleaching of copper from circuit boards of computer waste by Acidithiobacillus ferrooxidans

Gastrointestinal (GI) microflora is an important system in the host, as it has both pathogenic and probiotic bacteria. Most of the studies were focused on the human gut microflora and the available information on the intestinal microflora of goats was limited. This urged the need to inspect the impacts of the goat's gut microflora. Metagenomic investigation of probiotic bacteria in the GI tract of goat is one of the challenging streams because of the less available data of the uncultivable bacteria. In our report, comparative analysis of metagenomic and enrichment samples of goat intestinal content was done and this approach will be helpful in analyzing the identification of uncultivable and cultivable probiotic bacteria. This study mainly focused on three key probiotic adhesion genes, such as EF-Tu, mapA, and mub. The GI of four different goats were investigated for these genes. The data from this study showed that there is a wide diversity of these genes among goat intestinal samples.

Diversity of probiotic adhesion genes in the gastrointestinal tract of goats

Electronic waste or waste electrical and electronic equipment (WEEEs) is an emerging and fast-growing waste stream with complex characteristics. As per United Nations 'Global E-waste Monitor report, 2015' (Baldé et al., 2014), the global quantity of total e-waste generated in 2014 was around 41.8 million metric tonnes (MT). The presence of metals like copper, aluminium, iron and various precious metals like gold, silver, palladium, platinum, etc., in high concentrations, made e-waste an 'urban mine'. Bioleaching is one of the successful bio-hydrometallurgical method, which can be employed for metal recovery from different WEEEs. Recovery of precious metals like copper, gold and silver is possible at high concentrations from WEEEs using acidophilic mesophiles and thermophiles and some fungal species. The current paper mainly aims to reflect on e-waste generation, mechanisms of bioleaching and various microorganisms employed for the extraction of metals from the electronic waste.

World Review of Science, Technology and Sustainable Development

Microbiological leaching of metals and its recovery from waste electrical and electronic equipment: a review

Microbially induced concrete has emerged as an important area of research for high performance construction. This study examines the compressive strength, water absorption, Ultrasonic Pulse Velocity (UPV) and rapid chloride permeability test (RCPT) of concrete that are influenced by bacteria isolated from three different places (cement, urea godown and dry activated sludge dumped soil). These isolated bacterial strains were characterized by morphological, biochemical and molecular techniques as Bacillus sp. These bacteria were used in the concentration (106cells/ml) for making bacterial concrete mixtures. The experimental investigation was carried out to evaluate the influence of bacteria for 7, 14 and 28 days study. The compressive strength of concrete showed an increase of about 23.8 %, 23% and 15.3 % as compared to control concrete at 28 days. Similarly, water absorption rate decreased to 3.1 % to 3.8% water by its weight which is less than control 4.2%. The UPV values of the bacterial concrete are comparable to control concrete. The use of bacteria was to precipitate CaCO3 the micro environment. The bacterial degradation locally increases the pH and promotes the microbial deposition of carbonate as calcium carbonate which leads to increase in compressive strength.

Department of Structural and Geotechical Engineering

School of Civil Engineering

Indian Concrete Journal

Experimental investigation of bacterial concrete to improve compressive strength: A microbiology and civil engineering approach

Koozh is a popular South Indian traditional food made from finger millet (Eleucine corocana Gaertn.). The traditional preparation method was applied to other common millets, viz. Pearl millet [Pennisitum typhoides (Burm.f.) Stapf & C.E. Hubbard], Sorghum (Sorghum bicolor (L.) Moench and Maize (Zea mays L.). The fermentation process was monitored for microbial succession. The biochemical changes and sensory properties were evaluated and compared with traditional finger millet fermentation process. Microbial profile and biochemical changes in selected millets were identical to traditional fermentation process. Starch hydrolysers were the primary players in the initial hours (0 -10 hrs) of fermentation in all grains, while lactic acid bacteria (LAB) dominated the later hours (0 - 15 hrs). Starch hydrolysis was the major biochemical transformation occurred during the initial fermentation period, and in later conversion of sugar into acids took place which made the medium acidic. Koozh prepared from pearl millet and sorghum had sharp flavor and received acceptability from consumers, while Maize Koozh did not appeal to the consumers. This study is an attempt to add variety to traditional process and to improve commercial value and marketability.

Indian Journal of Traditional Knowledge

A study on the fermentation pattern of common millets in Koozh preparation - A traditional South Indian food

Department of Database Systems

School of Computer Science and Engineering

Food Biotechnology

Improvement of Riboflavin Production byLactobacillus fermentumIsolated from Yogurt

Riboflavin producing lactic acid bacteria were isolated from fermented milk samples. Lactobacillus fermentum MTCC 8711, which produced higher amount of riboflavin, was used for the fermentative production of riboflavin. Response surface methodology with central composite design was used for the optimization of the fermentation medium for riboflavin production. Peptone, beef extract, glucose and K2HPO4 of the MRS broth were selected as variables. Among the tested variables, beef extract, glucose and K2HPO4 showed significant effect on the riboflavin production. Higher concentration of K2HPO4 exhibited positive response on riboflavin production. The validation run based on the optimum production in response surface plot resulted in the maximum (9.43 mg L-1) riboflavin yield, which was almost equivalent to the predicted value of 9.63 mg L-1. The Lb. fermentum strain produced four folds higher riboflavin in the optimized medium when compared to the unoptimized medium (2.28 mg L-1). © 2011.

International Food Research Journal

Optimization of MRS media components using response surface methodology for the riboflavin production by Lactobacillus fermentum isolated from yoghurt sample

The objectives of this study were to obtain the combinatorial libraries in water and reverse micellar systems and to evaluate their catalytic activity applying the reverse micelles as microreactors under the restrictions of size and conformation. The amino acids, viz., Gly, Asp, His, Arg, and Leu were selected for polypeptide synthesis based on the reported bioinformatic approaches. The polypeptides were synthesized by carbodiimide method. The activity was defined as an increase in absorbance after 15 min of reaction with reference to control without amino acids using ABTS, catechol, and pyrogallol as the substrates for oxidase activity, ABTS/H2O2 as the substrates for peroxidase activity, and NIPAB as the substrate for hydrolase activity, with and without Zn2+, Cu2+, Mn2+ sulfates and hemin. The evidence of catalytic activity was observed in the synthesized combinatorial libraries. The presence of polypeptide chains was demonstrated by electrophoresis. © 2007 by Allerton Press, Inc.

Moscow University Chemistry Bulletin

Evidence of the catalytic activity of polypeptides artificially synthesized from conservative amino acids

The objectives of this study were to obtain the combinatorial libraries in water and reverse micellar systems and to evaluate their catalytic activity applying the reverse micelles as micro-reactors defined the restrictions of size and conformation. The amino acids, viz., Gly, Asp, His, Arg and Leu were selected for polypeptide synthesis based on the reported bioinformatic approaches. The polypeptides were synthesized by carbodiimide method. The activity was defined as increase in absorbance after 15 min of reaction with reference to control without amino acids using ABTS, catechol, pyrogallol as the substrates for oxidase activity, ABTSTH2O2 as the substrates for peroxidase activity and NIPAB as the substrate for hydrolase activity, with and without Zn2+, Cu2+, Mn2+ sulfates and hemin. The evidence of catalytic activity was observed in the synthesized combinatorial libraries. The presence of polypeptide chains was demonstrated by electrophoresis.

Vestnik Moskovskogo Universiteta Seriya 2 Khimiya

Evidence of catalytic activity of polypeptides artificially synthesized from conservative aminoacids

The applicability of artificial neural network (ANN) to predict the bioleaching of metals using from computer printed circuit boards (CPCB) and the influence of process parameters were studied. The influence of process parameters initial pH (1.6-2.4), pulp density (2%-13%), and the initial volume of Inoculum (5%-25%) were investigated on the rate of bioleaching of metals from CPCB. Network inputs were fed as initial pH, pulp density, and inoculum volume and with the extraction of Cu, Ag, and Au as output. The ANN was developed using the Levenberg-Marquardt algorithm and trained for modeling and prediction. The most fitting architectures for Cu, Ag, and Au were [4-5-5-2-1], [4-7-5-2-1], [4-7-1-1-1] trained with Levenberg-Marquardt algorithm, respectively. The R values were observed to be 0.996, 0.997, and 0.993 for Cu, Ag, and Au extraction predictions, respectively. The genetic algorithm model defined by ANN was used to achieve maximum extraction rates for Cu, Au, and Ag. The predicted data showed that there is a great capability of using ANN for the prediction of Cu, Ag, and Au extraction from CPCB through bioleaching process. Hence, the ANN model can be used to control the operational conditions for improved metals extraction through bioleaching.