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Ma S, Xu K, Ren H. Effect of mixing intensity on volatile fatty acids production in sludge alkaline fermentation: Insights from dissolved organic matter characteristics and functional microorganisms. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118801. [PMID: 37591099 DOI: 10.1016/j.jenvman.2023.118801] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/03/2023] [Accepted: 08/10/2023] [Indexed: 08/19/2023]
Abstract
Alkaline fermentation for volatile fatty acids (VFAs) production has shown potential as a viable approach to treat sewage sludge. The hydrolysis and acidogenesis of sludge are greatly influenced by mixing. However, the effects of mixing intensity on VFAs production in sludge alkaline fermentation (SAF) remain poorly understood. This study investigated the impacts of mixing intensity (30, 90 and 150 rpm continuous mixing, and 150 rpm intermittent mixing) on VFAs production, dissolved organic matter (DOM) characteristics, phospholipid fatty acid profiles and microbial population distribution in SAF. Results showed that 150 rpm continuous and intermittent mixing enhanced the hydrolysis of sludge, while 150 rpm intermittent mixing resulted in the highest VFAs production (3886 ± 266.1 mg COD/L). Analysis of fluorescent and molecular characteristics of DOM revealed that 150 rpm intermittent mixing facilitated the conversion of released DOM, especially proteins-like substances, into VFAs. The abundance of unsaturated and branched fatty acids of microbes increased under 150 rpm intermittent mixing, which could aid in DOM degradation and VFAs production. Firmicutes and Tissierella were enriched at 150 rpm intermittent mixing, which favored the maximum VFAs yield. Moreover, Firmicutes were found to be the key functional microorganisms influencing the yield of VFAs during SAF. This study provides an understanding about the mixing intensity effects on VFAs production during SAF, which could be helpful to improve the yield of VFAs.
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Affiliation(s)
- Sijia Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Ke Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
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Zou G, Bao D, Wang Y, Zhou S, Xiao M, Yang Z, Wang Y, Zhou Z. Alleviating product inhibition of Trichoderma reesei cellulase complex with a product-activated mushroom endoglucanase. BIORESOURCE TECHNOLOGY 2021; 319:124119. [PMID: 32957048 DOI: 10.1016/j.biortech.2020.124119] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Product inhibition of cellulase is a challenging issue in industrial processes. Here, we introduced a product-activated mushroom cellulase, PaCel3A from Polyporus arcularius, into Trichoderma reesei. The filter paper activity, carboxymethyl cellulase activity, and saccharification efficiency (substrate: pretreated rice straw, PRS) of transformants increased significantly with this enzyme (by 18.4-26.8%, 13.8-22.8%, and 17.0%, respectively). A mutant of PaCel3A, PaCel3AM, obtained based on B-factor analysis, saturated mutagenesis, and residual activity assay, showed improved thermostability. The PRS saccharification efficiency using the cellulase complex from T. reesei transformants overexpressing pacel3am increased by 56.4%-63.0%. In addition, the T. reesei cellulase complex obtained by adding the purified recombinant PaCel3AM from T. reesei (rCel3aM-tr) to hydrolyze PRS resulted in increased reducing sugar yields at all sampling points, outperforming the cellulase complexes without rCel3aM-tr. These results suggest that introducing product-activated cellulase genes is a simple and feasible method to alleviate the product inhibition of cellulase.
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Affiliation(s)
- Gen Zou
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China; CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Dapeng Bao
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China.
| | - Ying Wang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Sichi Zhou
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Meili Xiao
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Zhanshan Yang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Yinmei Wang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Zhihua Zhou
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
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Chakraborty S, Paul SK. Interaction of reactions and transport in lignocellulosic biofuel production. Curr Opin Chem Eng 2020. [DOI: 10.1016/j.coche.2020.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jiang S, Daly H, Xiang H, Yan Y, Zhang H, Hardacre C, Fan X. Microwave-assisted catalyst-free hydrolysis of fibrous cellulose for deriving sugars and biochemicals. Front Chem Sci Eng 2019. [DOI: 10.1007/s11705-019-1804-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Ma SJ, Ma HJ, Hu HD, Ren HQ. Effect of mixing intensity on hydrolysis and acidification of sewage sludge in two-stage anaerobic digestion: Characteristics of dissolved organic matter and the key microorganisms. WATER RESEARCH 2019; 148:359-367. [PMID: 30396101 DOI: 10.1016/j.watres.2018.10.058] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/18/2018] [Accepted: 10/21/2018] [Indexed: 06/08/2023]
Abstract
Mixing should be optimized in anaerobic digestion (AD) systems to achieve excellent biomaterials production in the sewage sludge (SS) management in wastewater treatment plant. AD depends on the coordinated activity of hydrolysis, acidification and methanogenesis. However, the effect of mixing intensity on characteristics of hydrolysis and acidification in AD of SS is still poorly understood. This study focused on the mixing intensity (30, 60, 90 and 120 rpm) effect on the characteristics of dissolved organic matter (DOM) and the key microorganisms in the hydrolysis and acidification of SS. Results showed that enhanced hydrolysis and acidification efficiency was obtained at mixing of 90 and 120 rpm (p < 0.05), while the maximum acetic acid (388 ± 21 mg/L) was produced at 90 rpm. Mixing at 90 rpm enhanced the release of protein and polysaccharide as well as humic acid. Further analyses of DOM molecular features revealed that 90 rpm led to the highest molecular diversity and easily biodegradable molecules (lipid and proteins/amino sugars), which contributed to the maximum hydrolysis and acidification efficiency. Firmicutes and Actinobacteria significantly increased with mixing intensity (p<0.05), and Chloroflexi and Fusobacteria were enriched at mixing of 90 rpm, which favored the hydrolysis of SS. The enrichment of Clostridium XI and Clostridium sensu stricto contributed to the acidification of DOM at 90 and 120 rpm. The results of this study can advance our knowledge about mixing intensity effects on the AD systems of SS. This research also showed how increasing mixing intensity to a relatively high speed can enhance the hydrolysis and acidification efficiency of SS.
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Affiliation(s)
- Si-Jia Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hai-Jun Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hai-Dong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hong-Qiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
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Dutta SK, Chakraborty S. Mixing effects on the kinetics and the dynamics of two-phase enzymatic hydrolysis of hemicellulose for biofuel production. BIORESOURCE TECHNOLOGY 2018; 259:276-285. [PMID: 29571171 DOI: 10.1016/j.biortech.2018.03.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/07/2018] [Accepted: 03/08/2018] [Indexed: 06/08/2023]
Abstract
This work uses a coupled experimental and modeling approach to explore the effects of macro- and micro-mixing on the kinetics and the dynamics of two-phase enzymatic hydrolysis of hemicellulose. Reactor mixing does not alter the non-competitive nature of product inhibition in hemicellulose hydrolysis by endoxylanase, but produces stronger inhibition that reduces the soluble sugar yield by 8-14.5%, as the mixing speed increases from 0 to 200 rpm. The kinetic constants (Km, Vmax, Kx) assume mass-transfer disguised values at 0-200 rpm. An optimal mixing strategy, comprising of 55-70 min of initial rapid convective macromixing followed by diffusive micromixing (without any macromixing) for the rest of the hydrolysis, increases xylose and reducing sugar yields by 6.3-8% and 13-20%, respectively, over continuous mixing at 200 rpm, for 1-5 mg/ml substrate loading at an optimum enzyme to substrate ratio of 1:20, with an energy saving of 94-96% over 24 h.
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Affiliation(s)
- Sajal Kanti Dutta
- Department of Chemical Engineering, Indian Institute of Technology, Kharagpur 721302, India
| | - Saikat Chakraborty
- Department of Chemical Engineering, Indian Institute of Technology, Kharagpur 721302, India; School of Energy Science and Engineering, Indian Institute of Technology, Kharagpur 721302, India.
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Villaverde J, Rubio-Bellido M, Lara-Moreno A, Merchan F, Morillo E. Combined use of microbial consortia isolated from different agricultural soils and cyclodextrin as a bioremediation technique for herbicide contaminated soils. CHEMOSPHERE 2018; 193:118-125. [PMID: 29127836 DOI: 10.1016/j.chemosphere.2017.10.172] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 10/30/2017] [Accepted: 10/31/2017] [Indexed: 06/07/2023]
Abstract
The phenylurea herbicide diuron is persistent in soil, water and groundwater and is considered to be a highly toxic molecule. The principal product of its biodegradation, 3,4-dichloroaniline, exhibits greater toxicity than diuron and is persistent in the environment. Five diuron degrading microbial consortia (C1C5), isolated from different agricultural soils, were investigated for diuron mineralization activity. The C2 consortium was able to mineralize 81.6% of the diuron in solution, while consortium C3 was only able to mineralize 22.9%. Isolated consortia were also tested in soil slurries and in all cases, except consortium C4, DT50 (the time required for the diuron concentration to decline to half of its initial value) was drastically reduced, from 700 days (non-inoculated control) to 546, 351, and 171 days for the consortia C5, C2, and C1, respectively. In order to test the effectiveness of the isolated consortium C1 in a more realistic scenario, soil diuron mineralization assays were performed under static conditions (40% of the soil water-holding capacity). A significant enhancement of diuron mineralization was observed after C1 inoculation, with 23.2% of the herbicide being mineralized in comparison to 13.1% for the control experiment. Hydroxypropyl-β-cyclodextrin, a biodegradable organic enhancer of pollutant bioavailability, used in combination with C1 bioaugmentation in static conditions, resulted in a significant decrease in the DT50 (214 days; 881 days, control experiment). To the best of our knowledge, this is the first report of the use of soil-isolated microbial consortia in combination with cyclodextrins proposed as a bioremediation technique for pesticide contaminated soils.
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Affiliation(s)
- J Villaverde
- Instituto de Recursos Naturales y Agrobiología (IRNAS-CSIC), Apartado 1052, 41080, Sevilla, Spain.
| | - M Rubio-Bellido
- Instituto de Recursos Naturales y Agrobiología (IRNAS-CSIC), Apartado 1052, 41080, Sevilla, Spain
| | - A Lara-Moreno
- Instituto de Recursos Naturales y Agrobiología (IRNAS-CSIC), Apartado 1052, 41080, Sevilla, Spain
| | - F Merchan
- Departamento de Microbiología y Parasitología, Universidad de Sevilla, Facultad de Farmacia, C/ Profesor García González, 2, 41012, Sevilla, Spain
| | - E Morillo
- Instituto de Recursos Naturales y Agrobiología (IRNAS-CSIC), Apartado 1052, 41080, Sevilla, Spain
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Gaikwad A. Interactions of mixing and reaction kinetics of depolymerization of cellulose to renewable fuels. CHEM ENG COMMUN 2017. [DOI: 10.1080/00986445.2017.1371015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ashwin Gaikwad
- Department of Chemical Engineering, Visvesvaraya National Institute of Technology, Nagpur, India
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