1
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Adekunle A, Ukaigwe S, Bezerra Dos Santos A, Iorhemen OT. Potential for curdlan recovery from aerobic granular sludge wastewater treatment systems - A review. CHEMOSPHERE 2024; 362:142504. [PMID: 38825243 DOI: 10.1016/j.chemosphere.2024.142504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/29/2024] [Accepted: 05/31/2024] [Indexed: 06/04/2024]
Abstract
The aerobic granular sludge (AGS) biotechnology has been explored for wastewater treatment for over two decades. AGS is gaining increased interest due to its enhanced treatment performance ability and the potential for resource recovery from AGS-based wastewater treatment systems. Resource recovery from AGS is a promising approach to sustainable wastewater treatment and attaining a circular economy in the wastewater management industry. Currently, research is at an advanced stage on recovering value-added resources such as phosphorus, polyhydroxyalkanoates, alginate-like exopolysaccharides, and tryptophan from waste aerobic granules. Recently, other value-added resources, including curdlan, have been identified in the aerobic granule matrix, and this may increase the sustainability of biotechnology in the wastewater industry. This paper provides an overview of AGS resource recovery potential. In particular, the potential for enhanced curdlan biosynthesis in the granule matrix and its recovery from AGS wastewater treatment systems is outlined.
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Affiliation(s)
- Adedoyin Adekunle
- School of Engineering, University of Northern British Columbia, 3333 University Way, Prince George, BC, V2N 4Z9, Canada
| | - Sandra Ukaigwe
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - André Bezerra Dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Oliver Terna Iorhemen
- School of Engineering, University of Northern British Columbia, 3333 University Way, Prince George, BC, V2N 4Z9, Canada.
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2
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Reed KB, Brooks SM, Wells J, Blake KJ, Zhao M, Placido K, d'Oelsnitz S, Trivedi A, Gadhiyar S, Alper HS. A modular and synthetic biosynthesis platform for de novo production of diverse halogenated tryptophan-derived molecules. Nat Commun 2024; 15:3188. [PMID: 38609402 PMCID: PMC11015028 DOI: 10.1038/s41467-024-47387-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 03/31/2024] [Indexed: 04/14/2024] Open
Abstract
Halogen-containing molecules are ubiquitous in modern society and present unique chemical possibilities. As a whole, de novo fermentation and synthetic pathway construction for these molecules remain relatively underexplored and could unlock molecules with exciting new applications in industries ranging from textiles to agrochemicals to pharmaceuticals. Here, we report a mix-and-match co-culture platform to de novo generate a large array of halogenated tryptophan derivatives in Escherichia coli from glucose. First, we engineer E. coli to produce between 300 and 700 mg/L of six different halogenated tryptophan precursors. Second, we harness the native promiscuity of multiple downstream enzymes to access unexplored regions of metabolism. Finally, through modular co-culture fermentations, we demonstrate a plug-and-play bioproduction platform, culminating in the generation of 26 distinct halogenated molecules produced de novo including precursors to prodrugs 4-chloro- and 4-bromo-kynurenine and new-to-nature halogenated beta carbolines.
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Affiliation(s)
- Kevin B Reed
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA
| | - Sierra M Brooks
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA
| | - Jordan Wells
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA
| | - Kristin J Blake
- Mass Spectrometry Facility, Department of Chemistry, The University of Texas at Austin, 105 E 24th Street, Austin, TX, USA
| | - Minye Zhao
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA
| | - Kira Placido
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA
| | - Simon d'Oelsnitz
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX, USA
| | - Adit Trivedi
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA
| | - Shruti Gadhiyar
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA
| | - Hal S Alper
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX, USA.
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX, USA.
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3
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Salar-García MJ, Ortiz-Martínez VM, Sánchez-Segado S, Valero Sánchez R, Sáez López A, Lozano Blanco LJ, Godínez-Seoane C. Sustainable Production of Biofuels and Biochemicals via Electro-Fermentation Technology. Molecules 2024; 29:834. [PMID: 38398584 PMCID: PMC10891623 DOI: 10.3390/molecules29040834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/04/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
The energy crisis and climate change are two of the most concerning issues for human beings nowadays. For that reason, the scientific community is focused on the search for alternative biofuels to conventional fossil fuels as well as the development of sustainable processes to develop a circular economy. Bioelectrochemical processes have been demonstrated to be useful for producing bioenergy and value-added products from several types of waste. Electro-fermentation has gained great attention in the last few years due to its potential contribution to biofuel and biochemical production, e.g., hydrogen, methane, biopolymers, etc. Conventional fermentation processes pose several limitations in terms of their practical and economic feasibility. The introduction of two electrodes in a bioreactor allows the regulation of redox instabilities that occur in conventional fermentation, boosting the overall process towards a high biomass yield and enhanced product formation. In this regard, key parameters such as the type of culture, the nature of the electrodes as well as the operating conditions are crucial in order to maximize the production of biofuels and biochemicals via electro-fermentation technology. This article comprises a critical overview of the benefits and limitations of this emerging bio-electrochemical technology and its contribution to the circular economy.
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Affiliation(s)
- María José Salar-García
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Alfonso XIII, Aulario C, 30203 Cartagena, Spain;
| | - Víctor Manuel Ortiz-Martínez
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Sergio Sánchez-Segado
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Raúl Valero Sánchez
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Alfonso XIII, Aulario C, 30203 Cartagena, Spain;
| | - Antonia Sáez López
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Luis Javier Lozano Blanco
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Carlos Godínez-Seoane
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
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4
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Jeong SH, Kim HJ, Lee SJ. New Target Gene Screening Using Shortened and Random sgRNA Libraries in Microbial CRISPR Interference. ACS Synth Biol 2023; 12:800-808. [PMID: 36787424 PMCID: PMC10028695 DOI: 10.1021/acssynbio.2c00595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
CRISPR interference (CRISPRi) screening has been used for identification of target genes related to specific phenotypes using single-molecular guide RNA (sgRNA) libraries. In CRISPRi screening, the sizes of random sgRNA libraries contained with the original target recognition sequences are large (∼1012). Here, we demonstrated that the length of the target recognition sequence (TRS) can be shortened in sgRNAs from the original 20 nucleotides (N20) to 9 nucleotides (N9) that is still sufficient for dCas9 to repress target genes in the xylose operon of Escherichia coli, regardless of binding to a promoter or open reading frame region. Based on the results, we constructed random sgRNA plasmid libraries with 5'-shortened TRS lengths, and identified xylose metabolic target genes by Sanger sequencing of sgRNA plasmids purified from Xyl- phenotypic cells. Next, the random sgRNA libraries were harnessed to screen for target genes to enhance violacein pigment production in synthetic E. coli cells. Seventeen target genes were selected by analyzing the redundancy of the TRS in sgRNA plasmids in dark purple colonies. Among them, seven genes (tyrR, pykF, cra, ptsG, pykA, sdaA, and tnaA) have been known to increase the intracellular l-tryptophan pool, the precursor of a violacein. Seventeen cells with a single deletion of each target gene exhibited a significant increase in violacein production. These results indicate that using shortened random TRS libraries for CRISPRi can be simple and cost-effective for phenotype-based target gene screening.
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Affiliation(s)
- Song Hee Jeong
- Department of Systems Biotechnology, and Institute of Microbiomics, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Hyun Ju Kim
- Department of Systems Biotechnology, and Institute of Microbiomics, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Sang Jun Lee
- Department of Systems Biotechnology, and Institute of Microbiomics, Chung-Ang University, Anseong 17546, Republic of Korea
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5
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Measurement and Correlation of Solubility of L–Tryptophan in Aqueous Solutions with a Wide Range of pH and Different Monovalent Counterions from 283.15 to 323.15 K. J SOLUTION CHEM 2022. [DOI: 10.1007/s10953-022-01229-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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6
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Biotechnological production of specialty aromatic and aromatic-derivative compounds. World J Microbiol Biotechnol 2022; 38:80. [PMID: 35338395 DOI: 10.1007/s11274-022-03263-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/05/2022] [Indexed: 10/18/2022]
Abstract
Aromatic compounds are an important class of chemicals with different industrial applications. They are usually produced by chemical synthesis from petroleum-derived feedstocks, such as toluene, xylene and benzene. However, we are now facing threats from the excessive use of fossil fuels causing environmental problems such as global warming. Furthermore, fossil resources are not infinite, and will ultimately be depleted. To cope with these problems, the sustainable production of aromatic chemicals from renewable non-food biomass is urgent. With this in mind, the search for alternative methodologies to produce aromatic compounds using low-cost and environmentally friendly processes is becoming more and more important. Microorganisms are able to produce aromatic and aromatic-derivative compounds from sugar-based carbon sources. Metabolic engineering strategies as well as bioprocess optimization enable the development of microbial cell factories capable of efficiently producing aromatic compounds. This review presents current breakthroughs in microbial production of specialty aromatic and aromatic-derivative products, providing an overview on the general strategies and methodologies applied to build microbial cell factories for the production of these compounds. We present and describe some of the current challenges and gaps that must be overcome in order to render the biotechnological production of specialty aromatic and aromatic-derivative attractive and economically feasible at industrial scale.
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7
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Vargas MA, Bernal C, Martínez R. Protease‐assisted process for tryptophan release from pumpkin (
Cucurbita maxima
) seed protein extracts. J FOOD PROCESS PRES 2022. [DOI: 10.1111/jfpp.16290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Marta A. Vargas
- Laboratorio de Tecnología Enzimática para Bioprocesos Departamento de Ingeniería en Alimentos Universidad de La Serena La Serena Chile
| | - Claudia Bernal
- Laboratorio de Tecnología Enzimática para Bioprocesos Departamento de Ingeniería en Alimentos Universidad de La Serena La Serena Chile
- Instituto de Investigación Multidisciplinaria en Ciencia y Tecnología Universidad de La Serena La Serena Chile
| | - Ronny Martínez
- Laboratorio de Tecnología Enzimática para Bioprocesos Departamento de Ingeniería en Alimentos Universidad de La Serena La Serena Chile
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8
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Liu S, Xu JZ, Zhang WG. Advances and prospects in metabolic engineering of Escherichia coli for L-tryptophan production. World J Microbiol Biotechnol 2022; 38:22. [PMID: 34989926 DOI: 10.1007/s11274-021-03212-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
As an important raw material for pharmaceutical, food and feed industry, highly efficient production of L-tryptophan by Escherichia coli has attracted a considerable attention. However, there are complicated and multiple layers of regulation networks in L-tryptophan biosynthetic pathway and thus have difficulty to rewrite the biosynthetic pathway for producing L-tryptophan with high efficiency in E. coli. This review summarizes the biosynthetic pathway of L-tryptophan and highlights the main regulatory mechanisms in E. coli. In addition, we discussed the latest metabolic engineering strategies achieved in E. coli to reconstruct the L-tryptophan biosynthetic pathway. Moreover, we also review a few strategies that can be used in E. coli to improve robustness and streamline of L-tryptophan high-producing strains. Lastly, we also propose the potential strategies to further increase L-tryptophan production by systematic metabolic engineering and synthetic biology techniques.
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Affiliation(s)
- Shuai Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China
| | - Jian-Zhong Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
| | - Wei-Guo Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
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9
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Shimizu K, Matsuoka Y. Feedback regulation and coordination of the main metabolism for bacterial growth and metabolic engineering for amino acid fermentation. Biotechnol Adv 2021; 55:107887. [PMID: 34921951 DOI: 10.1016/j.biotechadv.2021.107887] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 12/05/2021] [Accepted: 12/09/2021] [Indexed: 12/28/2022]
Abstract
Living organisms such as bacteria are often exposed to continuous changes in the nutrient availability in nature. Therefore, bacteria must constantly monitor the environmental condition, and adjust the metabolism quickly adapting to the change in the growth condition. For this, bacteria must orchestrate (coordinate and integrate) the complex and dynamically changing information on the environmental condition. In particular, the central carbon metabolism (CCM), monomer synthesis, and macromolecular synthesis must be coordinately regulated for the efficient growth. It is a grand challenge in bioscience, biotechnology, and synthetic biology to understand how living organisms coordinate the metabolic regulation systems. Here, we consider the integrated sensing of carbon sources by the phosphotransferase system (PTS), and the feed-forward/feedback regulation systems incorporated in the CCM in relation to the pool sizes of flux-sensing metabolites and αketoacids. We also consider the metabolic regulation of amino acid biosynthesis (as well as purine and pyrimidine biosyntheses) paying attention to the feedback control systems consisting of (fast) enzyme level regulation with (slow) transcriptional regulation. The metabolic engineering for the efficient amino acid production by bacteria such as Escherichia coli and Corynebacterium glutamicum is also discussed (in relation to the regulation mechanisms). The amino acid synthesis is important for determining the rate of ribosome biosynthesis. Thus, the growth rate control (growth law) is further discussed on the relationship between (p)ppGpp level and the ribosomal protein synthesis.
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Affiliation(s)
- Kazuyuki Shimizu
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan; Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan.
| | - Yu Matsuoka
- Department of Fisheries Distribution and Management, National Fisheries University, Shimonoseki, Yamaguchi 759-6595, Japan
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10
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Schoppel K, Trachtmann N, Mittermeier F, Sprenger GA, Weuster-Botz D. Metabolic control analysis of L-tryptophan producing Escherichia coli applying targeted perturbation with shikimate. Bioprocess Biosyst Eng 2021; 44:2591-2613. [PMID: 34519841 PMCID: PMC8536597 DOI: 10.1007/s00449-021-02630-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/27/2021] [Indexed: 12/26/2022]
Abstract
L-tryptophan production from glycerol with Escherichia coli was analysed by perturbation studies and metabolic control analysis. The insertion of a non-natural shikimate transporter into the genome of an Escherichia coli L-tryptophan production strain enabled targeted perturbation within the product pathway with shikimate during parallelised short-term perturbation experiments with cells withdrawn from a 15 L fed-batch production process. Expression of the shikimate/H+-symporter gene (shiA) from Corynebacterium glutamicum did not alter process performance within the estimation error. Metabolic analyses and subsequent extensive data evaluation were performed based on the data of the parallel analysis reactors and the production process. Extracellular rates and intracellular metabolite concentrations displayed evident deflections in cell metabolism and particularly in chorismate biosynthesis due to the perturbations with shikimate. Intracellular flux distributions were estimated using a thermodynamics-based flux analysis method, which integrates thermodynamic constraints and intracellular metabolite concentrations to restrain the solution space. Feasible flux distributions, Gibbs reaction energies and concentration ranges were computed simultaneously for the genome-wide metabolic model, with minimum bias in relation to the direction of metabolic reactions. Metabolic control analysis was applied to estimate elasticities and flux control coefficients, predicting controlling sites for L-tryptophan biosynthesis. The addition of shikimate led to enhanced deviations in chorismate biosynthesis, revealing a so far not observed control of 3-dehydroquinate synthase on L-tryptophan formation. The relative expression of the identified target genes was analysed with RT-qPCR. Transcriptome analysis revealed disparities in gene expression and the localisation of target genes to further improve the microbial L-tryptophan producer by metabolic engineering.
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Affiliation(s)
- Kristin Schoppel
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany
| | - Natalia Trachtmann
- Institute of Microbiology, University of Stuttgart, Allmandring 31, 70569, Stuttgart, Germany
| | - Fabian Mittermeier
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany
| | - Georg A Sprenger
- Institute of Microbiology, University of Stuttgart, Allmandring 31, 70569, Stuttgart, Germany
| | - Dirk Weuster-Botz
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany.
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11
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Amorim de Carvalho CD, Ferreira Dos Santos A, Tavares Ferreira TJ, Sousa Aguiar Lira VN, Mendes Barros AR, Bezerra Dos Santos A. Resource recovery in aerobic granular sludge systems: is it feasible or still a long way to go? CHEMOSPHERE 2021; 274:129881. [PMID: 33582539 DOI: 10.1016/j.chemosphere.2021.129881] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/26/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Lately, wastewater treatment plants are much often being designed as wastewater-resource factories inserted in circular cities. Among biological treatment technologies, aerobic granular sludge (AGS), considered an evolution of activated sludge (AS), has received great attention regarding its resource recovery potential. This review presents the state-of-the-art concerning the influence of operational parameters on the recovery of alginate-like exopolysaccharides (ALE), tryptophan, phosphorus, and polyhydroxyalkanoates (PHA) from AGS systems. The carbon to nitrogen ratio was identified as a parameter that plays an important role for the optimal production of ALE, tryptophan, and PHA. The sludge retention time effect is more pronounced for the production of ALE and tryptophan. Additionally, salinity levels in the bioreactors can potentially be manipulated to increase ALE and phosphorus yields simultaneously. Some existing knowledge gaps in the scientific literature concerning the recovery of these resources from AGS were also identified. Regarding industrial applications, tryptophan has the longest way to go. On the other hand, ALE production/recovery could be considered the most mature process if we take into account that existing alternatives for phosphorus and PHA production/recovery are optimized for activated sludge rather than granular sludge. Consequently, to maintain the same effectiveness, these processes likely could not be applied to AGS without undergoing some modification. Therefore, investigating to what extent these adaptations are necessary and designing alternatives is essential.
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Affiliation(s)
- Clara de Amorim de Carvalho
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Amanda Ferreira Dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | | | | | | | - André Bezerra Dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil.
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12
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Special Issue: Green Sustainable Chemical Processes. Processes (Basel) 2021. [DOI: 10.3390/pr9071097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sustainable chemical process engineering results from applying the principles of green chemistry or sustainable chemistry to chemical process engineering [...]
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13
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Liu L, Bilal M, Luo H, Iqbal HMN. Impact of Transcriptional Regulation by Crp, FruR, FlhD, and TyrR on L-tryptophan Biosynthesis in Escherichia coli. APPL BIOCHEM MICRO+ 2021. [DOI: 10.1134/s0003683821030091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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14
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Minliang C, Chengwei M, Lin C, Zeng AP. Integrated laboratory evolution and rational engineering of GalP/Glk-dependent Escherichia coli for higher yield and productivity of L-tryptophan biosynthesis. Metab Eng Commun 2021; 12:e00167. [PMID: 33665119 PMCID: PMC7907822 DOI: 10.1016/j.mec.2021.e00167] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 01/01/2023] Open
Abstract
L-Tryptophan (Trp) is a high-value aromatic amino acid with diverse applications in food and pharmaceutical industries. Although production of Trp by engineered Escherichia coli has been extensively studied, the need of multiple precursors for its synthesis and the complex regulations of the biosynthetic pathways make the achievement of a high product yield still very challenging. Metabolic flux analysis suggests that the use of a phosphoenolpyruvate:sugar phosphotransferase system (PTS) independent glucose uptake system, i.e. the galactose permease/glucokinase (GalP/Glk) system, can theoretically double the Trp yield from glucose. To explore this possibility, a PTS- and GalP/Glk-dependent E. coli strain was constructed from a previously rationally developed Trp producer strain S028. However, the growth rate of the S028 mutant was severely impaired. To overcome this problem, promoter screening for modulated gene expression of GalP/Glk was carried out, following by a batch mode of adaptive laboratory evolution (ALE) which resulted in a strain K3 with a similar Trp yield and concentration as S028. In order to obtain a more efficient Trp producer, a novel continuous ALE system was developed by combining CRISPR/Cas9-facilitated in vivo mutagenesis with real-time measurement of cell growth and online monitoring of Trp-mediated fluorescence intensity. With the aid of this automatic system (auto-CGSS), a promising strain T5 was obtained and fed-batch fermentations showed an increase of Trp yield by 19.71% with this strain compared with that obtained by the strain K3 (0.164 vs. 0.137 g/g). At the same time, the specific production rate was increased by 52.93% (25.28 vs. 16.53 mg/g DCW/h). Two previously engineered enzyme variants AroGD6G-D7A and AnTrpCR378F were integrated into the strain T5, resulting in a highly productive strain T5AA with a Trp yield of 0.195 g/g and a specific production rate of 28.83 mg/g DCW/h.
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Affiliation(s)
- Chen Minliang
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, D-21073, Hamburg, Germany
| | - Ma Chengwei
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, D-21073, Hamburg, Germany
| | - Chen Lin
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, D-21073, Hamburg, Germany
| | - An-Ping Zeng
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, D-21073, Hamburg, Germany
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15
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Luo H, Zheng P, Bilal M, Xie F, Zeng Q, Zhu C, Yang R, Wang Z. Efficient bio-butanol production from lignocellulosic waste by elucidating the mechanisms of Clostridium acetobutylicum response to phenolic inhibitors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 710:136399. [PMID: 31923698 DOI: 10.1016/j.scitotenv.2019.136399] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/24/2019] [Accepted: 12/27/2019] [Indexed: 05/12/2023]
Abstract
Lignocellulosic biomass is considered abundant renewable feedstock to constitute a green and environmentally friendly approach for biofuels (bio-butanol) production as an effective substitute for fossil resources. However, a variety of fermentable inhibitors can be generated in hydrolysates during the biomass pretreatment process. Among them, phenolics including phenolic acids and phenolic aldehydes are the most toxic inhibitors to solventogenic clostridia for bio-butanol production. This study elucidates the physiological mechanism of Clostridium acetobutylicum ATCC 824 response to phenolic inhibitors by the integration of kinetics and transcriptional analysis. Butanol fermentations were stressed by 0.4 g/L phenolic acids or 0.4 g/L phenolic aldehydes at 12 h at the beginning of solventogenesis. With post-stress for 12 h, butanol titer was 7.01 g/L in fermentation with phenolic acid stress, while only 5.82 g/L butanol was produced in the case of phenolic aldehydes stress. Reductions in the two fermentations were 27.6% and 40.0% in comparison with the control (without stress), indicated that phenolic aldehydes had a stronger inhibitory effect on solvents synthesis in C. acetobutylicum than phenolic acids. Additionally, the transcriptional analysis revealed that phenolics altered the gene expression profiles related to membrane transporters such as ATP-binding cassette (ABC)-transporter and phosphotransferase system (PTS), glycolysis, and heat shock proteins. The lower expression levels of PTS-related genes might result in reduced glucose consumption and finally inhibited solvents synthesis under phenolic aldehydes stress. Some genes encoding histidine kinase (CA_C0323, CA_C0903, and CA_C3319) were also affected by phenolics, which might inhibit sporulation. In conclusion, our results provide valuable guidance for the construction of robust strain to efficiently produce bio-butanol from lignocellulosic biomass.
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Affiliation(s)
- Hongzhen Luo
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Panli Zheng
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China
| | - Fang Xie
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China
| | - Qingwei Zeng
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China
| | - Chun Zhu
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China
| | - Rongling Yang
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China
| | - Zhaoyu Wang
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China
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16
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Shimizu K, Matsuoka Y. Redox rebalance against genetic perturbations and modulation of central carbon metabolism by the oxidative stress regulation. Biotechnol Adv 2019; 37:107441. [PMID: 31472206 DOI: 10.1016/j.biotechadv.2019.107441] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 08/04/2019] [Accepted: 08/23/2019] [Indexed: 12/11/2022]
Abstract
The micro-aerophilic organisms and aerobes as well as yeast and higher organisms have evolved to gain energy through respiration (via oxidative phosphorylation), thereby enabling them to grow much faster than anaerobes. However, during respiration, reactive oxygen species (ROSs) are inherently (inevitably) generated, and threaten the cell's survival. Therefore, living organisms (or cells) must furnish the potent defense systems to keep such ROSs at harmless level, where the cofactor balance plays crucial roles. Namely, NADH is the source of energy generation (catabolism) in the respiratory chain reactions, through which ROSs are generated, while NADPH plays important roles not only for the cell synthesis (anabolism) but also for detoxifying ROSs. Therefore, the cell must rebalance the redox ratio by modulating the fluxes of the central carbon metabolism (CCM) by regulating the multi-level regulation machinery upon genetic perturbations and the change in the growth conditions. Here, we discuss about how aerobes accomplish such cofactor homeostasis against redox perturbations. In particular, we consider how single-gene mutants (including pgi, pfk, zwf, gnd and pyk mutants) modulate their metabolisms in relation to cofactor rebalance (and also by adaptive laboratory evolution). We also discuss about how the overproduction of NADPH (by the pathway gene mutation) can be utilized for the efficient production of useful value-added chemicals such as medicinal compounds, polyhydroxyalkanoates, and amino acids, all of which require NADPH in their synthetic pathways. We then discuss about the metabolic responses against oxidative stress, where αketoacids play important roles not only for the coordination between catabolism and anabolism, but also for detoxifying ROSs by non-enzymatic reactions, as well as for reducing the production of ROSs by repressing the activities of the TCA cycle and respiration (via carbon catabolite repression). Thus, we discuss about the mechanisms (basic strategies) that modulate the metabolism from respiration to respiro-fermentative metabolism causing overflow, based on the role of Pyk activity, affecting the NADPH production at the oxidative pentose phosphate (PP) pathway, and the roles of αketoacids for the change in the source of energy generation from the oxidative phosphorylation to the substrate level phosphorylation.
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Affiliation(s)
- Kazuyuki Shimizu
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan; Institute of Advanced Biosciences, Keio university, Tsuruoka, Yamagata 997-0017, Japan.
| | - Yu Matsuoka
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan.
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