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29. Denitrification-induced carbonate precipitation by bio-composite material with Pseudomonas aeruginosa for simultaneous nitrate and cadmium remediation.

Author

Fang, Chaolin, Lin, Ruitao, Xu, Kaixuan, and Achal, Varenyam

Subjects
PSEUDOMONAS aeruginosa, NITRITE reductase, CADMIUM, NITRATE reductase, BICARBONATE ions, CARBONATE minerals, ALGINATES
Abstract

The presence of nitrate and heavy metals in wastewater are common but serious problem throughout the world. Thus, considering their toxicity, in the present study, denitrification-induced carbonate precipitation by Pseudomonas aeruginosa was researched in the simultaneous removal of nitrate and cadmium. Prior to the experimentation, P. aeruginosa was immobilized in bio-composite material (BCM) comprised of varying concentration of bentonite and alginate. The BCM with formulation 3% (m/v) bentonite and 1% (m/v) alginate (BA3) was found to more sustained and controlled release of bacterial cells in the solution, thus was utilized for bioremediation studies. The BCM with formulation BA3 effectively removed nitrate and Cd2+ by 93 and 74% (m/m), when their initial concentrations were 100 and 5 mg/L, respectively, in 24 h. Further, the P. aeruginosa cells inside the BCM were able to produce nitrite reductase and nitrate reductase in the spiked solution. Based on experimental results, denitrification by BCM reduced nitrate, generated alkalinity, and formed bicarbonate ions that, when reacting with Cd2+ ions, formed cadmium carbonate. The research presented in this study is important to know the significance of bio-composite material with denitrifiers in actively producing key enzymes of denitrification leading to simultaneous removal of nitrate and heavy metal from water. [ABSTRACT FROM AUTHOR]

Published
2023
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36. Assessment of soil degradation and chemical compositions in Rwandan tea-growing areas

Author

Jean de la Paix Mupenzi, Lanhai Li, Jiwen Ge, Achal Varenyam, Gabriel Habiyaremye, Nzayisenga Theoneste, and Kamanzi Emmanuel

Subjects
Chemical elements, Fertilizer use, pH, Soil degradation, Tea plantations, Geology, QE1-996.5
Abstract

This study has focused on the processes of soil degradation and chemical element concentration in tea-growing regions of Rwanda, Africa. Soil degradation accelerated by erosion is caused not only by topography but also by human activities. This soil degradation involves both the physical loss and reduction in the amount of topsoil associated with nutrient decline. Soil samples were collected from eleven tropical zones in Rwanda and from variable depth within each collecting site. Of these, Samples from three locations in each zone were analyzed in the laboratory, with the result that the pH of all soil samples is shown to be less than 5 (pH

Published
2011
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40. A review of microbial precipitation for sustainable construction

Author

Achal, Varenyam and Mukherjee, Abhijit

Subjects
Concrete -- Analysis -- Mechanical properties, Green buildings -- Analysis -- Mechanical properties, Green building (Construction) -- Analysis, Business, Construction and materials industries
Abstract

ABSTRACT Rapid urbanisation has accelerated consumption of concrete making it the most consumed artificial material. Present day concrete is one of the largest sources of anthropogenic greenhouse gas emission and [...]

Published
2015
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41. Ca-mediated alleviation of Cd²⁺ induced toxicity and improved Cd²⁺ biomineralization by Sporosarcina pasteurii

Author

Fang, Longyang, Niu, Qijian, Cheng, Liang, Jiang, Jianxiong, Yu, Yang-Yang, Chu, Jian, Achal, Varenyam, You, Tianyan, and School of Civil and Environmental Engineering

Subjects
Biomineralization, Microbial Induced Carbonate Precipitation, Environmental engineering [Engineering]
Abstract

Microbial induced carbonate precipitation has been widely used in the biomineralization of heavy metals Cd2+. However, the low Cd-tolerance of ureolytic bacteria limits the applications with only low Cd2+concentrations. In this study, we discovered a simple approach to significantly enhance the Cd2+ resistance of ureolytic bacteria through an immediate supplement of Ca2+. The Ca2+ protected the cells by reducing the extracellular and intracellular Cd2+ concentration by about 50%. As a result, the Cd2+ removal efficiency was notably improved by about 100% (52.72% to 99.43%, Cd = 5 mM) with Ca2+ supplement. Moreover, extremely high concentration of Cd2+ could be almost completely removed (99.46% at C0 = 20 mM and 99.60% at C0 = 50 mM) within 24 h. Microstructure analyses indicated that the mineralized precipitates were rhombohedral-shaped CdCO3, CaCO3, and (Ca0.67, Cd0.33)CO3. Furthermore, Ca2+ could also protect ureolytic bacteria against toxicity from other heavy metals. The authors would like to thank the supports from the program of Jiangsu Distinguished Professor and the Innovation/Entrepreneurship Program of Jiangsu Province, Jiangsu Province Key Project of Research and Development Plan (BE2020676), the China Postdoctoral Science Foundation (2020M671359), Initial Research Fund of Highly Specialized Personnel from Jiangsu University (4111370003), Senior Talent Funded Projects of Jiangsu University (17JDG016), and Project of Faculty of Agricultural Equipment of Jiangsu University (NZXB20200209), and Natural Science Foundation of Jiangsu Province (Grant no. BK20200914).

Published
2021

46. Biogenic treatment improves the durability and remediates the cracks of concrete structures

Author

Achal, Varenyam, Mukerjee, Abhijeet, and Reddy, M. Sudhakara

Subjects
Concrete -- Properties -- Analysis, Porosity -- Analysis, Building materials -- Usage -- Forecasts and trends, Calcium carbonate -- Usage -- Properties, Market trend/market analysis, Business, Construction and materials industries
Abstract

ABSTRACT Microbially induced calcium carbonate precipitation is a naturally occurring biological process that has various applications in remediation and restoration of range of building materials. In the present study the [...]

Published
2013
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49. Contributors

Author

A.J. Siddiqui, Tabassum, Achal, Varenyam, Awasarmol, Vishal V., Deokate, Ramesh, Dutta, Dimple P., Gaikar, Paresh, Ghule, Balaji G., Gore, Shyam K., Jadhav, Santosh S., Jadhav, Vijaykumar V., Jadhav, Gitanjali P., Jagadale, Sandhya, Kamble, Chetan, Khapate, Sunil R., Kim, Saeyoung, Mane, Rajaram S., Narwade, Sandesh H., Pak, James J., Patil, Sarita, Pawar, Pravina P., Raut, Siddheshwar D., Sangale, Sushil, Shaikh, Shoyebmohamad F., Shaikh, Zeenat A., Shinde, Nanasaheb M., Shinde, Pritamkumar V., Shirsat, Shubhangi D., Suryawanshi, Rushikesh R., Tumberphale, Umakant B., Wadhawa, Gurumeet, and Xia, Qixun

Published
2023
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