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Najar IN, Sharma P, Das R, Tamang S, Mondal K, Thakur N, Gandhi SG, Kumar V. From waste management to circular economy: Leveraging thermophiles for sustainable growth and global resource optimization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121136. [PMID: 38759555 DOI: 10.1016/j.jenvman.2024.121136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 04/24/2024] [Accepted: 05/09/2024] [Indexed: 05/19/2024]
Abstract
Waste of any origin is one of the most serious global and man-made concerns of our day. It causes climate change, environmental degradation, and human health problems. Proper waste management practices, including waste reduction, safe handling, and appropriate treatment, are essential to mitigate these consequences. It is thus essential to implement effective waste management strategies that reduce waste at the source, promote recycling and reuse, and safely dispose of waste. Transitioning to a circular economy with policies involving governments, industries, and individuals is essential for sustainable growth and waste management. The review focuses on diverse kinds of environmental waste sources around the world, such as residential, industrial, commercial, municipal services, electronic wastes, wastewater sewerage, and agricultural wastes, and their challenges in efficiently valorizing them into useful products. It highlights the need for rational waste management, circularity, and sustainable growth, and the potential of a circular economy to address these challenges. The article has explored the role of thermophilic microbes in the bioremediation of waste. Thermophiles known for their thermostability and thermostable enzymes, have emerged to have diverse applications in biotechnology and various industrial processes. Several approaches have been explored to unlock the potential of thermophiles in achieving the objective of establishing a zero-carbon sustainable bio-economy and minimizing waste generation. Various thermophiles have demonstrated substantial potential in addressing different waste challenges. The review findings affirm that thermophilic microbes have emerged as pivotal and indispensable candidates for harnessing and valorizing a range of environmental wastes into valuable products, thereby fostering the bio-circular economy.
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Affiliation(s)
- Ishfaq Nabi Najar
- Fermentation and Microbial Biotechnology Division, CSIR IIIM, Jammu, India
| | - Prayatna Sharma
- Department of Microbiology, School of Life Sciences, Sikkim University, Gairigaon, Tadong, Gangtok, 737102, Sikkim, India
| | - Rohit Das
- Department of Microbiology, School of Life Sciences, Sikkim University, Gairigaon, Tadong, Gangtok, 737102, Sikkim, India
| | - Sonia Tamang
- Department of Microbiology, School of Life Sciences, Sikkim University, Gairigaon, Tadong, Gangtok, 737102, Sikkim, India
| | | | - Nagendra Thakur
- Department of Microbiology, School of Life Sciences, Sikkim University, Gairigaon, Tadong, Gangtok, 737102, Sikkim, India
| | | | - Vinod Kumar
- Fermentation and Microbial Biotechnology Division, CSIR IIIM, Jammu, India.
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Vanapalli KR, Bhar R, Maity SK, Dubey BK, Kumar S, Kumar V. Life cycle assessment of fermentative production of lactic acid from bread waste based on process modelling using pinch technology. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167051. [PMID: 37717758 DOI: 10.1016/j.scitotenv.2023.167051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/18/2023] [Accepted: 09/11/2023] [Indexed: 09/19/2023]
Abstract
Bread waste (BW), a rich source of fermentable carbohydrates, has the potential to be a sustainable feedstock for the production of lactic acid (LA). In our previous work, the LA concentration of 155.4 g/L was achieved from BW via enzymatic hydrolysis, which was followed by a techno-economic analysis of the bioprocess. This work evaluates the relative environmental performance of two scenarios - neutral and low pH fermentation processes for polymer-grade LA production from BW using a cradle-to-gate life cycle assessment (LCA). The LCA was based on an industrial-scale biorefinery process handling 100 metric tons BW per day modelled using Aspen Plus. The LCA results depicted that wastewater from anaerobic digestion (AD) (42.3-51 %) and cooling water utility (34.6-39.5 %), majorly from esterification, were the critical environmental hotspots for LA production. Low pH fermentation yielded the best results compared to neutral pH fermentation, with 11.4-11.5 % reduction in the overall environmental footprint. Moreover, process integration by pinch technology, which enhanced thermal efficiency and heat recovery within the process, led to a further reduction in the impacts by 7.2-7.34 %. Scenario and sensitivity analyses depicted that substituting ultrapure water with completely softened water and sustainable management of AD wastewater could further improve the environmental performance of the processes.
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Affiliation(s)
- Kumar Raja Vanapalli
- Department of Civil Engineering, National Institute of Technology, Mizoram, Aizawl, Mizoram 796012, India
| | - Rajarshi Bhar
- Department of Civil Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
| | - Sunil K Maity
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502284, Telangana, India
| | - Brajesh K Dubey
- Department of Civil Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
| | - Sandeep Kumar
- Department of Civil & Environmental Engineering, Old Dominion University, Norfolk, VA 23529, United States
| | - Vinod Kumar
- School of Water, Energy and Environment, Cranfield University, Cranfield MK43 0AL, UK; Department of Bioscience and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand 247667, India; C-Source Renewables Limited, Summit House, 4 - 5 Mitchell Street, Edinburgh EH6 7BD, UK.
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Liao M, Dong R, Li L, Liu X, Wang Y, Bai Y, Luo H, Yao B, Huang H, Tu T. High Production of Maltooligosaccharides in the Starch Liquefaction Process: A Study on the Hyperthermophilic Mechanism of α-Amylase. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:6480-6489. [PMID: 36959740 DOI: 10.1021/acs.jafc.3c00665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The efficient production of high-value-added bioproducts from starchy substances requires α-amylases with hyperthermophilic properties for industrial starch liquefaction. In this study, two hyperthermophilic α-amylases with significant differences in thermostability, PfAmy and TeAmy, were comparatively studied through structural analysis, domain swapping, and site-directed mutagenesis, finding that three residues, His152, Cys166, and His168, located in domain B were the main contributors to hyperthermostability. The effects of these three residues were strongly synergistic, causing the optimum temperature for the mutant K152H/A166C/E168H of TeAmy to shift to 95-100 °C and stabilize at 90 °C without Ca2+. Compared to PfAmy and TeAmy, the mutant K152H/A166C/E168H, respectively, exhibited 1.7- and 2.5-times higher starch hydrolysis activity at 105 °C and pH 5.5 (10411 ± 70 U/mg) and released 1.1- and 1.7-times more maltooligosaccharides from 1% starch. This work has interpreted the hyperthermophilic mechanism of α-amylase and thereby providing a potential candidate for the efficient industrial conversion of starch to bioproducts.
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Affiliation(s)
- Min Liao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ruyue Dong
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Lanxue Li
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaoqing Liu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yaru Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yingguo Bai
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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