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Tang J, Yang H, Pu Y, Hu Y, Huang J, Jin N, He X, Wang XC. Caproic acid production from food waste using indigenous microbiota: Performance and mechanisms. BIORESOURCE TECHNOLOGY 2023; 387:129687. [PMID: 37595807 DOI: 10.1016/j.biortech.2023.129687] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
Caproic acid (CA) production from food waste (FW) is a promising way for waste recycling, while the fermentation processes need further exploration. In this study, FW acidogenic fermentation under different pH (uncontrolled, 4, 5, 6) using indigenous microbiota was investigated. Result showed that substrate hydrolysis, carbohydrate degradation and acidogenesis increased with the increase of pH. Although various microbial communities were observed in FW, lactic acid bacteria (Lactobacillus and Limosilactobacillus) were enriched at pH lower than 6, resulting in lactic acid accumulation. CA (88.24 mM) was produced at pH 6 accounting for 31.23% of the total product carbon. The enriched lactic acid bacteria were directionally replaced by chain elongators (Caproicibacter, Clostridium_sensu_stricto, unclassified_Ruminococcaceae) at pH 6, and carbohydrates in FW were firstly transformed into lactic acid, then to butyrate and CA through lactate-based chain elongation processes. This work provided a novel CA fermentation pathway and further enriched the FW valorization.
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Affiliation(s)
- Jialing Tang
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Hao Yang
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Yunhui Pu
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China; College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Yisong Hu
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China
| | - Jin Huang
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Ni Jin
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Xinrui He
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Xiaochang C Wang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China
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2
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Dahiya S, Mohan SV. Co-fermenting lactic acid and glucose towards caproic acid production. CHEMOSPHERE 2023; 328:138491. [PMID: 36963586 DOI: 10.1016/j.chemosphere.2023.138491] [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: 08/25/2022] [Revised: 02/20/2023] [Accepted: 03/21/2023] [Indexed: 06/18/2023]
Abstract
The functional role of lactate (HLac), as a co-substrate along with glucose (Glu) as well as an electron donor for the synthesis of caproic acid (HCa), a medium chain fatty acid (MCFAs) was studied. A varied HLac and Glu ratios were thus investigated in fed-batch anaerobic reactors (R1-R5) operated at pH 6 with a heat-treated anaerobic consortium. R1 and R5 were noted as controls and operated with sole Glu and HLac, respectively. Strategically, ethanol (HEth) was additionally supplemented as co-electron donor after the production of short chain carboxylic acids (SCCAs) for chain elongation in all the reactors. The reactor operated with HLac and Glu in a ratio of 0.25:0.75 (1.25 g/L (HLac) and 3.75 g/L (Glu)) showed the highest HCa production of 1.86 g/L. R5 operated with solely HLac yielded propionic acid (HPr) as the major product which further led to the higher valeric acid (HVa) production of 1.1 g/L within the reactor. Butyric acid (HBu) was observed in R1, which used Glu as carbon source alone indicating the importance of HLac as electron co-donor. Clostridium observed as the most dominant genera in shotgun metagenome sequencing in R2 and R3, the reactors that produced the highest HCa in comparison to other studied reactors. The study thus provided insight into the importance of substrate and electron donor and their supplementation strategies during the production of MCFAs.
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Affiliation(s)
- Shikha Dahiya
- Bioengineering and Environmental Science Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, 500 007, India; Academy of Scientific & Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - S Venkata Mohan
- Bioengineering and Environmental Science Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, 500 007, India; Academy of Scientific & Innovative Research (AcSIR), Ghaziabad, 201002, India.
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3
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Myers KS, Ingle AT, Walters KA, Fortney NW, Scarborough MJ, Donohue TJ, Noguera DR. Comparison of metagenomes from fermentation of various agroindustrial residues suggests a common model of community organization. Front Bioeng Biotechnol 2023; 11:1197175. [PMID: 37260833 PMCID: PMC10228549 DOI: 10.3389/fbioe.2023.1197175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 04/27/2023] [Indexed: 06/02/2023] Open
Abstract
The liquid residue resulting from various agroindustrial processes is both rich in organic material and an attractive source to produce a variety of chemicals. Using microbial communities to produce chemicals from these liquid residues is an active area of research, but it is unclear how to deploy microbial communities to produce specific products from the different agroindustrial residues. To address this, we fed anaerobic bioreactors one of several agroindustrial residues (carbohydrate-rich lignocellulosic fermentation conversion residue, xylose, dairy manure hydrolysate, ultra-filtered milk permeate, and thin stillage from a starch bioethanol plant) and inoculated them with a microbial community from an acid-phase digester operated at the wastewater treatment plant in Madison, WI, United States. The bioreactors were monitored over a period of months and sampled to assess microbial community composition and extracellular fermentation products. We obtained metagenome assembled genomes (MAGs) from the microbial communities in each bioreactor and performed comparative genomic analyses to identify common microorganisms, as well as any community members that were unique to each reactor. Collectively, we obtained a dataset of 217 non-redundant MAGs from these bioreactors. This metagenome assembled genome dataset was used to evaluate whether a specific microbial ecology model in which medium chain fatty acids (MCFAs) are simultaneously produced from intermediate products (e.g., lactic acid) and carbohydrates could be applicable to all fermentation systems, regardless of the feedstock. MAGs were classified using a multiclass classification machine learning algorithm into three groups, organisms fermenting the carbohydrates to intermediate products, organisms utilizing the intermediate products to produce MCFAs, and organisms producing MCFAs directly from carbohydrates. This analysis revealed common biological functions among the microbial communities in different bioreactors, and although different microorganisms were enriched depending on the agroindustrial residue tested, the results supported the conclusion that the microbial ecology model tested was appropriate to explain the MCFA production potential from all agricultural residues.
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Affiliation(s)
- Kevin S. Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Abel T. Ingle
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Kevin A. Walters
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - Nathaniel W. Fortney
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Matthew J. Scarborough
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United States
| | - Timothy J. Donohue
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - Daniel R. Noguera
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
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4
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Ho Ahn J, Hwan Jung K, Seok Lim E, Min Kim S, Ok Han S, Um Y. Recent advances in microbial production of medium chain fatty acid from renewable carbon resources: a comprehensive review. BIORESOURCE TECHNOLOGY 2023; 381:129147. [PMID: 37169199 DOI: 10.1016/j.biortech.2023.129147] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/29/2023] [Accepted: 05/04/2023] [Indexed: 05/13/2023]
Abstract
Microbial production of medium chain length fatty acids (MCFAs) from renewable resources is becoming increasingly important in establishing a sustainable and clean chemical industry. This review comprehensively summarizes current advances in microbial MCFA production from renewable resources. Detailed information is provided on two major MCFA production pathways using various renewable resources and other auxiliary pathways supporting MCFA production to help understand the fundamentals of bio-based MCFA production. In addition, conventional and well-studied MCFA producers are classified into two categories, natural and synthetic producers, and their characteristics on MCFA production are outlined. Moreover, various engineering strategies employed to achieve the highest MCFAs production up to date are showcased together with key enzymes suggested for MCFA overproduction. Finally, future challenges and perspectives are discussed towards more efficient production of bio-based MCFA production.
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Affiliation(s)
- Jung Ho Ahn
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Kweon Hwan Jung
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Eui Seok Lim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Sang Min Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea.
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5
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Zhao J, Yao Y, Li D, Zhu W, Xiao H, Xie M, Xiong Y, Wu J, Ni Q, Zhang M, Xu H. Metagenome and metabolome insights into the energy compensation and exogenous toxin degradation of gut microbiota in high-altitude rhesus macaques (Macaca mulatta). NPJ Biofilms Microbiomes 2023; 9:20. [PMID: 37081021 PMCID: PMC10119431 DOI: 10.1038/s41522-023-00387-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 03/29/2023] [Indexed: 04/22/2023] Open
Abstract
There have been many reports on the genetic mechanism in rhesus macaques (RMs) for environmental adaptation to high altitudes, but the synergistic involvement of gut microbiota in this adaptation remains unclear. Here we performed fecal metagenomic and metabolomic studies on samples from high- and low-altitude populations to assess the synergistic role of gut microbiota in the adaptation of RMs to high-altitude environments. Microbiota taxonomic annotation yielded 7471 microbiota species. There were 37 bacterial species whose abundance was significantly enriched in the high-altitude populations, 16 of which were previously reported to be related to the host's dietary digestion and energy metabolism. Further functional gene enrichment found a stronger potential for gut microbiota to synthesize energy substrate acetyl-CoA using CO2 and energy substrate pyruvate using oxaloacetate, as well as a stronger potential to transform acetyl-CoA to energy substrate acetate in high-altitude populations. Interestingly, there were no apparent differences between low-altitude and high-altitude populations in terms of genes enriched in the main pathways by which the microbiota consumed the three energy substrates, and none of the three energy substrates were detected in the fecal metabolites. These results strongly suggest that gut microbiota plays an important energy compensatory role that helps RMs to adapt to high-altitude environments. Further functional enrichment after metabolite source analysis indicated the abundance of metabolites related to the degradation of exogenous toxins was also significantly higher in high-altitude populations, which suggested a contributory role of gut microbiota to the degradation of exogenous toxins in wild RMs adapted to high-altitude environments.
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Affiliation(s)
- Junsong Zhao
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China
- College of Agronomy and Life Sciences, Zhaotong University, Zhaotong, 657000, China
| | - Yongfang Yao
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China
| | - Diyan Li
- School of Pharmacy, Chengdu University, Chengdu, 610106, China
| | - Wei Zhu
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Hongtao Xiao
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China
| | - Meng Xie
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China
| | - Ying Xiong
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China
| | - Jiayun Wu
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China
| | - Qingyong Ni
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Mingwang Zhang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Huailiang Xu
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
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6
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Regueira A, Turunen R, Vuoristo KS, Carballa M, Lema JM, Uusitalo J, Mauricio-Iglesias M. Model-aided targeted volatile fatty acid production from food waste using a defined co-culture microbial community. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159521. [PMID: 36270363 DOI: 10.1016/j.scitotenv.2022.159521] [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: 07/14/2022] [Revised: 10/10/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
The production of volatile fatty acids (VFA) is gaining momentum due to their central role in the emerging carboxylate platform. Particularly, the production of the longest VFA (from butyrate to caproate) is desired due to their increased economic value and easier downstream processing. While the use of undefined microbial cultures is usually preferred with organic waste streams, the use of defined microbial co-culture processes could tackle some of their drawbacks such as poor control over the process outcome, which often leads to low selectivity for the desired products. However, the extensive experimentation needed to design a co-culture system hinders the use of this technology. In this work, a workflow based on the combined use of mathematical models and wet experimentation is proposed to accelerate the design of novel bioprocesses. In particular, a co-culture consisting of Pediococcus pentosaceus and Megaphaera cerevisiae is used to target the production of high-value odd- and even‑carbon VFA. An unstructured kinetic model was developed, calibrated and used to design experiments with the goal of increasing the selectivity for the desired VFA, which were experimentally validated. In the case of even‑carbon VFA, the experimental validation showed an increase of 38 % in caproate yield and, in the case of enhanced odd‑carbon VFA experiments, the yield of butyrate and caproate diminished by 62 % and 94 %, respectively, while propionate became one of the main end products and valerate yield value increased from 0.007 to 0.085 gvalearte per gconsumed sugar. The workflow followed in this work proved to be a sound tool for bioprocess design due to its capacity to explore and design new experiments in silico in a fast way and ability to quickly adapt to new scenarios.
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Affiliation(s)
- A Regueira
- CRETUS, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; Center for Microbial Ecology and Technology (CMET), Ghent University, 9000 Gent, Belgium; Center for Advanced Process Technology for Urban Resource recovery (CAPTURE), Frieda Saeysstraat 1, 9000 Gent, Belgium.
| | - R Turunen
- Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, Tietotie 2, 02044, VTT, Espoo, Finland
| | - K S Vuoristo
- Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, Tietotie 2, 02044, VTT, Espoo, Finland
| | - M Carballa
- CRETUS, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - J M Lema
- CRETUS, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - J Uusitalo
- Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, Tietotie 2, 02044, VTT, Espoo, Finland
| | - M Mauricio-Iglesias
- CRETUS, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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7
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Crognale S, Massimi A, Sbicego M, Braguglia CM, Gallipoli A, Gazzola G, Gianico A, Tonanzi B, Di Pippo F, Rossetti S. Ecology of food waste chain-elongating microbiome. Front Bioeng Biotechnol 2023; 11:1157243. [PMID: 37113665 PMCID: PMC10126515 DOI: 10.3389/fbioe.2023.1157243] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/31/2023] [Indexed: 04/29/2023] Open
Abstract
Microbial chain elongation has emerged as a valuable bioprocess for obtaining marketable products, such as medium chain fatty acids usable in several industrial applications, from organic waste. The understanding of the microbiology and microbial ecology in these systems is crucial to apply these microbiomes in reliable production processes controlling microbial pathways to promote favourable metabolic processes, which will in turn increase product specificity and yields. In this research, the dynamics, cooperation/competition and potentialities of bacterial communities involved in the long-term lactate-based chain elongation process from food waste extract were evaluated under different operating conditions by DNA/RNA amplicon sequencing and functional profile prediction. The feeding strategies and the applied organic loading rates strongly affected the microbial community composition. The use of food waste extract promoted the selection of primary fermenters (i.e., Olsenella, Lactobacillus) responsible for the in situ production of electron donors (i.e., lactate). The discontinuous feeding and the organic loading rate 15 gCOD L-1 d-1 selected the best performing microbiome in which microbes coexist and cooperate to complete the chain elongation process. Both at DNA and RNA level, this microbiome was composed by the lactate producer Olsenella, the short chain fatty acids producers Anaerostipes, Clostridium sensu stricto 7, C. sensu stricto 12, Corynebacterium, Erysipelotrichaceae UCG-004, F0332, Leuconostoc, and the chain elongator Caproiciproducens. This microbiome also showed the highest predicted abundance of short-chain acyl-CoA dehydrogenase, the functional enzyme responsible for the chain elongation process. The combined approach herein used allowed to study the microbial ecology of chain elongation process from food waste by identifying the main functional groups, establishing the presence of potential biotic interactions within the microbiomes, and predicting metabolic potentialities. This study provided pivotal indications for the selection of high-performance microbiome involved in caproate production from food waste that can serve as a basis for further improving system performance and engineering the process scale-up.
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8
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Liu C, Du Y, Zheng J, Qiao Z, Luo H, Zou W. Production of caproic acid by Rummeliibacillus suwonensis 3B-1 isolated from the pit mud of strong-flavor baijiu. J Biotechnol 2022; 358:33-40. [PMID: 36049550 DOI: 10.1016/j.jbiotec.2022.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 08/24/2022] [Accepted: 08/24/2022] [Indexed: 11/18/2022]
Abstract
Caproic acid is the precursor of ethyl caproate, the main representative flavor substance of strong-flavor baijiu (SFB). Caproic acid-producing bacteria are considered to be the most important type of acid-producing microorganisms in the pit mud of the SFB ecosystem. In this study, the Rummeliibacillus suwonensis 3B-1 with a high yield of caproic acid (4.064g/L) was screened from SFB pit mud. The genome of the R. suwonensis 3B-1 was sequenced, the total size was found to be 4,117,671bp and a calculated GC content of 35.86%. The caproic acid biosynthesis pathway was identified and analyzed, and it showed that 3B-1 could not only use ethanol, but it could also use glucose and other carbon sources as substrates to produce caproic acid. According to the genome analysis and with an optimized medium, the optimal conditions for caproic acid production were yeast powder at 3g/L, sodium acetate at 15g/L, and 1% biotin at 8mL/100mL. The yield of caproic acid reached 4.627g/L, an increase of 13.9%, which was higher than that of general caproic acid bacteria. This is the first report of the synthesis of caproic acid by R. suwonensis. This strain could be used to produce caproic acid, an artificial pit mud preparation, and/or an enhanced inoculum in the production of SFB.
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Affiliation(s)
- Chaojie Liu
- College of Bioengineering, Sichuan University of Science & Engineering, Yibin, Sichuan 644005, China
| | - Yuanfen Du
- College of Bioengineering, Sichuan University of Science & Engineering, Yibin, Sichuan 644005, China
| | - Jia Zheng
- Key Laboratory of Wuliangye-flavor Liquor Solid-state Fermentation, China National Light Industry, Wuliangye Group, Yibin, Sichuan 644007, China
| | - Zongwei Qiao
- Key Laboratory of Wuliangye-flavor Liquor Solid-state Fermentation, China National Light Industry, Wuliangye Group, Yibin, Sichuan 644007, China
| | - Huibo Luo
- College of Bioengineering, Sichuan University of Science & Engineering, Yibin, Sichuan 644005, China
| | - Wei Zou
- College of Bioengineering, Sichuan University of Science & Engineering, Yibin, Sichuan 644005, China.
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9
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Viacava K, Qiao J, Janowczyk A, Poudel S, Jacquemin N, Meibom KL, Shrestha HK, Reid MC, Hettich RL, Bernier-Latmani R. Meta-omics-aided isolation of an elusive anaerobic arsenic-methylating soil bacterium. THE ISME JOURNAL 2022; 16:1740-1749. [PMID: 35338334 PMCID: PMC9213503 DOI: 10.1038/s41396-022-01220-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 02/24/2022] [Accepted: 03/07/2022] [Indexed: 12/12/2022]
Abstract
Soil microbiomes harbour unparalleled functional and phylogenetic diversity. However, extracting isolates with a targeted function from complex microbiomes is not straightforward, particularly if the associated phenotype does not lend itself to high-throughput screening. Here, we tackle the methylation of arsenic (As) in anoxic soils. As methylation was proposed to be catalysed by sulfate-reducing bacteria. However, to date, there are no available anaerobic isolates capable of As methylation, whether sulfate-reducing or otherwise. The isolation of such a microorganism has been thwarted by the fact that the anaerobic bacteria harbouring a functional arsenite S-adenosylmethionine methyltransferase (ArsM) tested to date did not methylate As in pure culture. Additionally, fortuitous As methylation can result from the release of non-specific methyltransferases upon lysis. Thus, we combined metagenomics, metatranscriptomics, and metaproteomics to identify the microorganisms actively methylating As in anoxic soil-derived microbial cultures. Based on the metagenome-assembled genomes of microorganisms expressing ArsM, we isolated Paraclostridium sp. strain EML, which was confirmed to actively methylate As anaerobically. This work is an example of the application of meta-omics to the isolation of elusive microorganisms.
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Affiliation(s)
- Karen Viacava
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Environmental Microbiology Laboratory, CH-1015, Lausanne, Switzerland.,Soil Science Group, Institute of Geography, University of Bern, Bern, Switzerland
| | - Jiangtao Qiao
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Environmental Microbiology Laboratory, CH-1015, Lausanne, Switzerland
| | - Andrew Janowczyk
- Bioinformatics Core Facility, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Suresh Poudel
- BioSciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Nicolas Jacquemin
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Environmental Microbiology Laboratory, CH-1015, Lausanne, Switzerland.,Translational Bioinformatics and Statistics, Department of Oncology, Université de Lausanne, Lausanne, Switzerland
| | - Karin Lederballe Meibom
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Environmental Microbiology Laboratory, CH-1015, Lausanne, Switzerland
| | - Him K Shrestha
- BioSciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Genome Science and Technology Graduate School, University of Tennessee, Knoxville, TN, USA
| | - Matthew C Reid
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA
| | - Robert L Hettich
- BioSciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Rizlan Bernier-Latmani
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Environmental Microbiology Laboratory, CH-1015, Lausanne, Switzerland.
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10
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Kim H, Kang S, Sang BI. Metabolic cascade of complex organic wastes to medium-chain carboxylic acids: A review on the state-of-the-art multi-omics analysis for anaerobic chain elongation pathways. BIORESOURCE TECHNOLOGY 2022; 344:126211. [PMID: 34710599 DOI: 10.1016/j.biortech.2021.126211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Medium-chain carboxylic acid (MCCA) production from organic wastes has attracted much attention because of their higher energy contents and diverse applications. Anaerobic reactor microbiomes are stable and resilient and have resulted in efficient performance during many years of operation for thousands of full-scale anaerobic digesters worldwide. The method underlying how the relevant microbial pathways contribute to elongate carbon chains in reactor microbiomes is important. In particular, the reverse β-oxidation pathway genes are critical to upgrading short-chain fermentation products to MCCAs via a chain elongation (CE) process. Diverse genomics and metagenomics studies have been conducted in various fields, ranging from intracellular metabolic pathways to metabolic cascades between different strains. This review covers taxonomic approach to culture processes depending on types of organic wastes and the deeper understanding of genome and metagenome-scale CE pathway construction, and the co-culture and multi-omics technology that should be addressed in future research.
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Affiliation(s)
- Hyunjin Kim
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seongcheol Kang
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Byoung-In Sang
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
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11
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Zhang Y, Pan X, Zuo J, Hu J. Production of n-caproate using food waste through thermophilic fermentation without addition of external electron donors. BIORESOURCE TECHNOLOGY 2022; 343:126144. [PMID: 34673194 DOI: 10.1016/j.biortech.2021.126144] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
The effectiveness of producing n-caproate from food waste without external electron donors (EDs) was investigated through batch and semi-continuous fermentation. The maximum concentration of n-caproate reached 10,226.28 mg COD/L during semi-continuous fermentation. The specificity for n-caproate was the highest at 40.19 ± 3.95%, and the soluble COD conversion rate of n-caproate reached up to 22.50 ± 1.09% at the end of batch fermentation. The production of n-caproate was coupled with the generation of lactate as an ED to facilitate chain elongation reactions. When lactate was used as the only substrate, n-butyrate (64.12 ± 20.11%) markedly dominated the products, instead of n-caproate (0.63 ± 0.07%). Microbial community analysis revealed that Caproiciproducens, Rummeliibacillus, and Clostridium_sensu_stricto_12 were the key genera related to n-caproate production. In addition to n-caproate, n-butyrate dominated the products in batch and semi-continuous fermentation with a maximum specificity of 47.59 ± 3.39%. Clostridium_sensu_stricto_7 was committed to producing n-butyrate from lactate.
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Affiliation(s)
- Yanyan Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xinrong Pan
- College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, China
| | - Jiane Zuo
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China.
| | - Jiamin Hu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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12
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Wang J, Yin Y. Biological production of medium-chain carboxylates through chain elongation: An overview. Biotechnol Adv 2021; 55:107882. [PMID: 34871718 DOI: 10.1016/j.biotechadv.2021.107882] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/01/2021] [Accepted: 11/28/2021] [Indexed: 12/15/2022]
Abstract
Medium chain carboxylates (MCCs) have wide applications in various industries, but the traditional MCCs production methods are costly and unsustainable. Anaerobic fermentation offers a more scalable, economical and eco-friendly platform for producing MCCs through chain elongation which converts short chain carboxylates and electron donor into more valuable MCCs. However, the underlying microbial pathways are not well understood. In this review, biological production of MCCs through chain elongation is introduced elaborately, including the metabolic pathways, electron donor and substrates, microorganisms and influencing factors. Then, the strategies for enhancing MCCs production are extensively analyzed and summarized, along with the technologies for MCCs separation from the fermentation broth. Finally, challenges and perspectives concerning the large-scale MCCs production are proposed, providing suggestions for the future research. Extensive review demonstrated that anaerobic fermentation has great potential in achieving economical and sustainable MCCs production from complex organic substrates, including organic waste streams, which would significantly broaden the application of MCCs, especially in the renewable energy field. An interdisciplinary approach with knowledge from microbiology and biochemistry to chemical separations and environmental engineering is required to use this promising technology as a valorization method for converting organic biomass or organic wastes into valuable MCCs.
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Affiliation(s)
- Jianlong Wang
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China; Beijing Key Laboratory of Radioactive Waste Treatment, Tsinghua University, Beijing 100084, PR China.
| | - Yanan Yin
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China
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13
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Lu S, Jin H, Wang Y, Tao Y. Genome-Wide Transcriptomic Analysis of n-Caproic Acid Production in Ruminococcaceae Bacterium CPB6 with Lactate Supplementation. J Microbiol Biotechnol 2021; 31:1533-1544. [PMID: 34489376 PMCID: PMC9705837 DOI: 10.4014/jmb.2107.07009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022]
Abstract
n-Caproic acid (CA) is gaining increased attention due to its high value as a chemical feedstock. Ruminococcaceae bacterium strain CPB6 is an anaerobic mesophilic bacterium that is highly prolific in its ability to perform chain elongation of lactate to CA. However, little is known about the genome-wide transcriptional analysis of strain CPB6 for CA production triggered by the supplementation of exogenous lactate. In this study, cultivation of strain CPB6 was carried out in the absence and presence of lactate. Transcriptional profiles were analyzed using RNA-seq, and differentially expressed genes (DEGs) between the lactate-supplemented cells and control cells without lactate were analyzed. The results showed that lactate supplementation led to earlier CA p,roduction, and higher final CA titer and productivity. 295 genes were substrate and/or growth dependent, and these genes cover crucial functional categories. Specifically, 5 genes responsible for the reverse β-oxidation pathway, 11 genes encoding ATP-binding cassette (ABC) transporters, 6 genes encoding substrate-binding protein (SBP), and 4 genes encoding phosphotransferase system (PTS) transporters were strikingly upregulated in response to the addition of lactate. These genes would be candidates for future studies aiming at understanding the regulatory mechanism of lactate conversion into CA, as well as for the improvement of CA production in strain CPB6. The findings presented herein reveal unique insights into the biomolecular effect of lactate on CA production at the transcriptional level.
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Affiliation(s)
- Shaowen Lu
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China
| | - Hong Jin
- School of Basic Medical Science, Chengdu Medical College, Chengdu 610083, P.R. China
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama, Alabama 36849, USA
| | - Yong Tao
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China,Faculty of Bioengineering, Sichuan University of Science and Engineering, Xueyuan Street 180#, Huixing Rd. Zigong 643000, P.R. China,Corresponding author Phone: 86-028-82890211 Fax: 86-028-82890211 E-mail:
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14
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Wu Q, Jiang Y, Chen Y, Liu M, Bao X, Guo W. Opportunities and challenges in microbial medium chain fatty acids production from waste biomass. BIORESOURCE TECHNOLOGY 2021; 340:125633. [PMID: 34315125 DOI: 10.1016/j.biortech.2021.125633] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/16/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
Medium chain fatty acids (MCFAs) that produced from affordable waste biomass via chain elongation (CE) technology are recognized as the potential alternatives to part fossil-derived chemicals, contributing to the sustainable development of economy and environment. The purpose of this review is to provide comprehensive analyses on the opportunities and challenges of MCFAs production and application. First, both two microbial MCFAs synthesis pathways of reverse β-oxidation and fatty acid biosynthesis were introduced/compared in detail to give readers a thorough understanding of the CE process, with the expectation of further boosting MCFAs production by well distinguishing them. Furthermore, the six key MCFAs production bottlenecks, corresponding research progresses, and possible solutions were analyzed. Five major MCFAs production strategies with their production mechanism, performances, and characteristics were also critically assessed. Additionally, the commercial production status was introduced, and future alternative production mode and research priorities were also recommended.
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Affiliation(s)
- Qinglian Wu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Yong Jiang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Ying Chen
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Xian Bao
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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15
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Zhou W, Liao Z, Wu Z, Suyama T, Zhang W. Analysis of the difference between aged and degenerated pit mud microbiome in fermentation cellars for Chinese Luzhou-flavor baijiu by metatranscriptomics. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2021; 101:4621-4631. [PMID: 33474773 DOI: 10.1002/jsfa.11105] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/10/2021] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUD Chinese Luzhou-flavor baijiu (LFB) was fermented in an underground cellar, and the bottom and side of the cellar were covered with pit muds (PMs), where the metabolic activity of the microorganisms had a significant effect on the LFB quality. PMs can be divided into aged pit mud (AP) and degenerated pit mud (DP), thus, the qualities of LFB generated from AP and DP were different. In this essay, metatranscriptomics method was applied to illustrate the differences of the two PMs, as well as to search out the pivotal microorganisms and genes influencing the quality of LFB. RESULTS Archaea, Clostridium and some thermophilic microorganisms might bring significant effect in AP, while the active eukaryota and Anaeromyxobacter would cause degeneration in PM. Also, the metabolism of carbohydrate and amino acid were more active in AP. What is more, carbohydrate, amino acid and their derivant can produce important organic acids via the activity of the microorganisms in PMs. There were eight critical enzymes noticed in the organic acids metabolic pathway, which were more actively expressed in AP, demonstrating active expression of the critical genes related to organic acid metabolism could have a positive effect on LFB quality. CONCLUSION This study identified specific differences in active microorganisms, active expressed genes and the expression levels of key genes in vital metabolic pathway between AP and DP. Which may be the actual reason for the differences in the quality of LFB made from different PMs. Mastering these results will provide assistance to improve the quality of LFB. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Wen Zhou
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China
- Department of Liquor and Food Engineering, Sichuan Technology and Business College, Dujiangyan, China
| | - Zuomin Liao
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China
| | - Zhengyun Wu
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China
| | - Taikei Suyama
- Akashi National College of Technology, Akashi, Japan
| | - Wenxue Zhang
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China
- School of Liquor-Making Engineering, Sichuan University Jinjiang College, Meishan, China
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16
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Lim JJ, Dutta M, Dempsey JL, Lehmler HJ, MacDonald J, Bammler T, Walker C, Kavanagh TJ, Gu H, Mani S, Cui JY. Neonatal Exposure to BPA, BDE-99, and PCB Produces Persistent Changes in Hepatic Transcriptome Associated With Gut Dysbiosis in Adult Mouse Livers. Toxicol Sci 2021; 184:83-103. [PMID: 34453844 PMCID: PMC8557404 DOI: 10.1093/toxsci/kfab104] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Recent evidence suggests that complex diseases can result from early life exposure to environmental toxicants. Polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) and remain a continuing risk to human health despite being banned from production. Developmental BPA exposure mediated-adult onset of liver cancer via epigenetic reprogramming mechanisms has been identified. Here, we investigated whether the gut microbiome and liver can be persistently reprogrammed following neonatal exposure to POPs, and the associations between microbial biomarkers and disease-prone changes in the hepatic transcriptome in adulthood, compared with BPA. C57BL/6 male and female mouse pups were orally administered vehicle, BPA, BDE-99 (a breast milk-enriched PBDE congener), or the Fox River PCB mixture (PCBs), once daily for three consecutive days (postnatal days [PND] 2-4). Tissues were collected at PND5 and PND60. Among the three chemicals investigated, early life exposure to BDE-99 produced the most prominent developmental reprogramming of the gut-liver axis, including hepatic inflammatory and cancer-prone signatures. In adulthood, neonatal BDE-99 exposure resulted in a persistent increase in Akkermansia muciniphila throughout the intestine, accompanied by increased hepatic levels of acetate and succinate, the known products of A. muciniphila. In males, this was positively associated with permissive epigenetic marks H3K4me1 and H3K27, which were enriched in loci near liver cancer-related genes that were dysregulated following neonatal exposure to BDE-99. Our findings provide novel insights that early life exposure to POPs can have a life-long impact on disease risk, which may partly be regulated by the gut microbiome.
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Affiliation(s)
- Joe Jongpyo Lim
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Moumita Dutta
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Joseph L Dempsey
- Division of Gastroenterology, Department of Medicine, School of Medicine, University of Washington, Seattle, Washington, USA,Center for Microbiome Sciences and Therapeutics, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa, USA
| | - James MacDonald
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Theo Bammler
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Cheryl Walker
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas 77030, USA,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA,Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA,Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Haiwei Gu
- Arizona Metabolomics Laboratory, College of Health Solutions, Arizona State University, Pheonix, Arizona 85004, USA
| | - Sridhar Mani
- Department of Medicine, Molecular Pharmacology and Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA,To whom correspondence should be addressed at Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Seattle, WA 98105, USA. E-mail:
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17
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Butyryl/Caproyl-CoA:Acetate CoA-transferase: cloning, expression and characterization of the key enzyme involved in medium-chain fatty acid biosynthesis. Biosci Rep 2021; 41:229427. [PMID: 34338280 PMCID: PMC8360832 DOI: 10.1042/bsr20211135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/07/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
Coenzyme A transferases (CoATs) are important enzymes involved in carbon chain elongation, contributing to medium-chain fatty acid (MCFA) biosynthesis. For example, butyryl-CoA:acetate CoA transferase (BCoAT) is responsible for the final step of butyrate synthesis from butyryl-CoA. However, little is known about caproyl-CoA:acetate CoA-transferase (CCoAT), which is responsible for the final step of caproate synthesis from caproyl-CoA. In the present study, two CoAT genes from Ruminococcaceae bacterium CPB6 and Clostridium tyrobutyricum BEY8 were identified by gene cloning and expression analysis. Enzyme assays and kinetic studies were carried out using butyryl-CoA or caproyl-CoA as the substrate. CPB6-CoAT can catalyze the conversion of both butyryl-CoA into butyrate and caproyl-CoA into caproate, but its catalytic efficiency with caproyl-CoA as the substrate was 3.8-times higher than that with butyryl-CoA. In contrast, BEY8-CoAT had only BCoAT activity, not CCoAT activity. This demonstrated the existence of a specific CCoAT involved in chain elongation via the reverse β-oxidation pathway. Comparative bioinformatics analysis showed the presence of a highly conserved motif (GGQXDFXXGAXX) in CoATs, which is predicted to be the active center. Single point mutations in the conserved motif of CPB6-CoAT (Asp346 and Ala351) led to marked decreases in the activity for butyryl-CoA and caproyl-CoA, indicating that the conserved motif is the active center of CPB6-CoAT and that Asp346 and Ala351 have a significant impact on the enzymatic activity. This work provides insight into the function of CCoAT in caproic acid biosynthesis and improves understanding of the chain elongation pathway for MCFA production.
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18
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Contreras-Dávila CA, Esveld J, Buisman CJN, Strik DPBTB. nZVI Impacts Substrate Conversion and Microbiome Composition in Chain Elongation From D- and L-Lactate Substrates. Front Bioeng Biotechnol 2021; 9:666582. [PMID: 34211964 PMCID: PMC8239352 DOI: 10.3389/fbioe.2021.666582] [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: 02/10/2021] [Accepted: 05/25/2021] [Indexed: 12/12/2022] Open
Abstract
Medium-chain carboxylates (MCC) derived from biomass biorefining are attractive biochemicals to uncouple the production of a wide array of products from the use of non-renewable sources. Biological conversion of biomass-derived lactate during secondary fermentation can be steered to produce a variety of MCC through chain elongation. We explored the effects of zero-valent iron nanoparticles (nZVI) and lactate enantiomers on substrate consumption, product formation and microbiome composition in batch lactate-based chain elongation. In abiotic tests, nZVI supported chemical hydrolysis of lactate oligomers present in concentrated lactic acid. In fermentation experiments, nZVI created favorable conditions for either chain-elongating or propionate-producing microbiomes in a dose-dependent manner. Improved lactate conversion rates and n-caproate production were promoted at 0.5-2 g nZVI⋅L-1 while propionate formation became relevant at ≥ 3.5 g nZVI⋅L-1. Even-chain carboxylates (n-butyrate) were produced when using enantiopure and racemic lactate with lactate conversion rates increased in nZVI presence (1 g⋅L-1). Consumption of hydrogen and carbon dioxide was observed late in the incubations and correlated with acetate formation or substrate conversion to elongated products in the presence of nZVI. Lactate racemization was observed during chain elongation while isomerization to D-lactate was detected during propionate formation. Clostridium luticellarii, Caproiciproducens, and Ruminococcaceae related species were associated with n-valerate and n-caproate production while propionate was likely produced through the acrylate pathway by Clostridium novyi. The enrichment of different potential n-butyrate producers (Clostridium tyrobutyricum, Lachnospiraceae, Oscillibacter, Sedimentibacter) was affected by nZVI presence and concentrations. Possible theories and mechanisms underlying the effects of nZVI on substrate conversion and microbiome composition are discussed. An outlook is provided to integrate (bio)electrochemical systems to recycle (n)ZVI and provide an alternative reducing power agent as durable control method.
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Affiliation(s)
| | - Johan Esveld
- Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - Cees J N Buisman
- Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - David P B T B Strik
- Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
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19
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Microbial Ecological Mechanism for Long-Term Production of High Concentrations of n-Caproate via Lactate-Driven Chain Elongation. Appl Environ Microbiol 2021; 87:AEM.03075-20. [PMID: 33741616 DOI: 10.1128/aem.03075-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/10/2021] [Indexed: 12/11/2022] Open
Abstract
Lactate-driven chain elongation (LCE) has emerged as a new biotechnology to upgrade organic waste streams into a valuable biochemical and fuel precursor, medium-chain carboxylate, n-caproate. Considering that a low cost of downstream extraction is critical for biorefinery technology, a high concentration of n-caproate production is very important to improve the scale-up of the LCE process. We report here that in a nonsterile open environment, the n-caproate concentration was increased from the previous record of 25.7 g·liter-1 to a new high level of 33.7 g·liter-1 (76.8 g chemical oxygen demand [COD]·liter - 1), with the highest production rate being 11.5 g·liter-1·day-1 (26.2 g COD·liter - 1·day-1). In addition, the LCE process remained stable, with an average concentration of n-caproate production of 20.2 ± 5.62 g·liter-1 (46.1 ± 12.8 g COD·liter - 1) for 780 days. Dynamic changes in taxonomic composition integrated with metagenomic data reveal the microbial ecology for long-term production of high concentrations of n-caproate: (i) the core microbiome is related to efficient functional groups, such as Ruminococcaceae (with functional strain CPB6); (ii) the core bacteria can maintain stability for long-term operation; (iii) the microbial network has relatively low microbe-microbe interaction strength; and (iv) low relative abundance and variety of competitors. The network structure could be shaped by hydraulic retention time (HRT) over time, and long-term operation at an HRT of 8 days displayed higher efficacy.IMPORTANCE Our research revealed the microbial network of the LCE reactor microbiome for n-caproate production at high concentrations, which will provide a foundation for designing or engineering the LCE reactor microbiome to recover n-caproate from organic waste streams in the future. In addition, the hypothetical model of the reactor microbiome that we proposed may offer guidance for researchers to find the underlying microbial mechanism when they encounter low-efficiency n-caproate production from the LCE process. We anticipate that our research will rapidly advance LCE biotechnology with the goal of promoting the sustainable development of human society.
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20
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Direct Conversion of Food Waste Extract into Caproate: Metagenomics Assessment of Chain Elongation Process. Microorganisms 2021; 9:microorganisms9020327. [PMID: 33562834 PMCID: PMC7915914 DOI: 10.3390/microorganisms9020327] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 12/30/2022] Open
Abstract
In a circular economy strategy, waste resources can be used for the biological production of high added-value substances, such as medium chain fatty acids (MCFAs), thus minimising waste and favouring a sustainable process. This study investigates single-stage fermentation processes for the production of MCFAs in a semi-continuous reactor treating the extract of real food waste (FW), without the addition of external electron donors. Two sequential acidogenic fermentation tests were carried out at an organic loading rate (OLR) of 5 and 15 gCOD L−1d−1 with a hydraulic retention time of 4 days and pH controlled at 6 ± 0.2. The highest level of caproate (4.8 g L−1) was observed at OLR of 15 gCOD L−1d−1 with a microbiome mainly composed by lactate-producing Actinomyces, Atopobium, and Olsenella species and caproate-producing Pseudoramibacter. Metagenomic analysis revealed the presence of key enzymes for the production of lactate, such as lactate dehydrogenase and pyruvate ferredoxin oxidoreductase, as well as several enzymes involved in the reverse β-oxidation pathway, thus suggesting the occurrence of a lactate-based chain elongation process.
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21
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Candry P, Ganigué R. Chain elongators, friends, and foes. Curr Opin Biotechnol 2021; 67:99-110. [PMID: 33529974 DOI: 10.1016/j.copbio.2021.01.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 01/02/2021] [Accepted: 01/07/2021] [Indexed: 12/14/2022]
Abstract
Bioproduction of medium chain carboxylic acids has recently emerged as an alternative strategy to valorize low-value organic waste and side-streams. Key to this route is chain elongation, an anaerobic microbial process driven by ethanol, lactic acid, or carbohydrates. Because these technologies use wastes as feedstocks, mixed microbial communities are often considered as biocatalysts. Understanding and steering these microbiomes is key to optimize bioprocess performance. From a meta-analysis of publicly available sequencing data, we (i) explore how the current collection of isolated chain elongators compares to microbiome members, (ii) discuss the main beneficial and antagonistic interactions with community partners, and (iii) identify the key research gaps and needs to help understand chain elongation microbiomes, and design/steer these novel bioproduction processes.
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Affiliation(s)
- Pieter Candry
- Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700, USA
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
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22
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Liu B, Popp D, Müller N, Sträuber H, Harms H, Kleinsteuber S. Three Novel Clostridia Isolates Produce n-Caproate and iso-Butyrate from Lactate: Comparative Genomics of Chain-Elongating Bacteria. Microorganisms 2020; 8:microorganisms8121970. [PMID: 33322390 PMCID: PMC7764203 DOI: 10.3390/microorganisms8121970] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023] Open
Abstract
The platform chemicals n-caproate and iso-butyrate can be produced by anaerobic fermentation from agro-industrial residues in a process known as microbial chain elongation. Few lactate-consuming chain-elongating species have been isolated and knowledge on their shared genetic features is still limited. Recently we isolated three novel clostridial strains (BL-3, BL-4, and BL-6) that convert lactate to n-caproate and iso-butyrate. Here, we analyzed the genetic background of lactate-based chain elongation in these isolates and other chain-elongating species by comparative genomics. The three strains produced n-caproate, n-butyrate, iso-butyrate, and acetate from lactate, with the highest proportions of n-caproate (18%) for BL-6 and of iso-butyrate (23%) for BL-4 in batch cultivation at pH 5.5. They show high genomic heterogeneity and a relatively small core-genome size. The genomes contain highly conserved genes involved in lactate oxidation, reverse β-oxidation, hydrogen formation and either of two types of energy conservation systems (Rnf and Ech). Including genomes of another eleven experimentally validated chain-elongating strains, we found that the chain elongation-specific core-genome encodes the pathways for reverse β-oxidation, hydrogen formation and energy conservation, while displaying substantial genome heterogeneity. Metabolic features of these isolates are important for biotechnological applications in n-caproate and iso-butyrate production.
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Affiliation(s)
- Bin Liu
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany; (B.L.); (D.P.); (H.S.); (H.H.)
| | - Denny Popp
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany; (B.L.); (D.P.); (H.S.); (H.H.)
| | - Nicolai Müller
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany;
| | - Heike Sträuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany; (B.L.); (D.P.); (H.S.); (H.H.)
| | - Hauke Harms
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany; (B.L.); (D.P.); (H.S.); (H.H.)
| | - Sabine Kleinsteuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany; (B.L.); (D.P.); (H.S.); (H.H.)
- Correspondence: ; Tel.: +49-341-235-1325
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23
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Fermentation of Organic Residues to Beneficial Chemicals: A Review of Medium-Chain Fatty Acid Production. Processes (Basel) 2020. [DOI: 10.3390/pr8121571] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Medium-chain fatty acids (MCFAs) have a variety of uses in the production of industrial chemicals, food, and personal care products. These compounds are often produced through palm refining, but recent work has demonstrated that MCFAs can also be produced through the fermentation of complex organic substrates, including organic waste streams. While “chain elongation” offers a renewable platform for producing MCFAs, there are several limitations that need to be addressed before full-scale implementation becomes widespread. Here, we review the history of work on MCFA production by both pure and mixed cultures of fermenting organisms, and the unique metabolic features that lead to MCFA production. We also offer approaches to address the remaining challenges and increase MCFA production from renewable feedstocks.
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24
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Cloning and characterization of a L-lactate dehydrogenase gene from Ruminococcaceae bacterium CPB6. World J Microbiol Biotechnol 2020; 36:182. [PMID: 33170386 DOI: 10.1007/s11274-020-02958-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/03/2020] [Indexed: 10/23/2022]
Abstract
Lactate are proved to be attractive electron donor for the production of n-caproic acid (CA) that is a high value-added fuel precursor and chemical feedstock, but little is known about molecular mechanism of lactate transformation. In the present study, the gene for L-lactate dehydrogenase (LDH, EC.1.1.1.27) from a Ruminococcaceae strain CPB6 was cloned and expressed in Escherichia coli BL21 (DE3) with plasmid pET28a. The recombinant LDH exhibited molecular weight of 36-38 kDa in SDS-PAGE. The purified LDH was found to have the maximal oxidation activity of 29.6 U/mg from lactate to pyruvate at pH 6.5, and the maximal reduction activity of 10.4 U/mg from pyruvate to lactate at pH 8.5, respectively. Strikingly, its oxidative activity predominates over reductive activity, leading to a 17-fold increase for the utilization of lactate in E. coli/pET28a-LDH than E. coli/pET28a. The CPB6 LDH gene encodes a 315 amino acid protein sharing 42.19% similarity with Clostridium beijerinckii LDH, and lower similarity with LDHs of other organisms. Significant difference were observed between the CPB6 LDH and C. beijerinckii and C. acetobutylicum LDH in the predicted tertiary structure and active center. Further, X-ray crystal structure analysis need to be performed to verify the specific active center of the CPB6 LDH and its role in the conversion of lactate into CA.
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25
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Yao Y, Yan L, Chen H, Wu N, Wang W, Wang D. Cyclocarya paliurus polysaccharides alleviate type 2 diabetic symptoms by modulating gut microbiota and short-chain fatty acids. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2020; 77:153268. [PMID: 32663709 DOI: 10.1016/j.phymed.2020.153268] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/06/2020] [Accepted: 06/19/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Cyclocarya paliurus polysaccharide (CCPP), a primary active component in the leaves of Cyclocarya paliurus (Batal.) Iljinsk (C. paliurus), has the ability to treat type 2 diabetes mellitus (T2DM), but cannot be digested by our digestive system. Therefore, mechanisms of regulating the gut microbiota and intestinal metabolites might exist. PURPOSE To reveal the potential mechanism of CCPP treatment, this study aimed to investigate the alterations of the gut microbiota and intestinal metabolites especially short chain fatty acids (SCFAs) in type 2 diabetic rats. STUDY DESIGN AND METHODS Type 2 diabetic rat models were developed, and the therapeutic effects of CCPP were evaluated. Metagenomics analysis was utilized to analyze the alterations to the gut microbiota, and UHPLC-QTOF/MS-based untargeted metabolomics analysis of colon contents was used to identify the differential intestinal metabolites. GC/MS was used to measure the SCFAs in rat's colon contents and human fecal inoculums. Furthermore, the expression of SCFA receptors including GPR41, GPR43 and GPR109a was verified by qRT-PCR and the concentration of glucagon-like peptide-1(GLP-1) and peptide tyrosinetyrosine (PYY) was measured by Elisa. RESULTS Inhibition of the blood glucose levels and improvements in glucose tolerance and serum lipid parameters were observed after CCPP treatment. Eleven SCFA-producing species including Ruminococcus_bromii, Anaerotruncus_colihominis, Clostridium_methylpentosum, Roseburia_intestinalis, Roseburia_hominis, Clostridium_asparagiforme, Pseudoflavonifractor_capillosus, Intestinimonas_butyriciproducens, Intestinimonas_sp._GD2, Oscillibacter_valericigenes and Oscillibacter_ruminantium were clearly increased in the CCPP group. Furthermore, our study indicated that CCPP increases the production of SCFAs both in vivo and in vitro, and the gut microbiota are the key factor of this process. The SCFA receptors including GPR41, GPR43 and GPR109a, were significantly stimulated in the CCPP treated rats, which was accompanied by the upregulated expression of GLP-1 and PYY. CONCLUSION These results demonstrated that CCPP could alleviate type 2 diabetic symptoms by increasing the SCFA-producing bacteria, promoting the production of SCFAs and upregulating SCFA-GLP1/PYY associated sensory mediators.
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MESH Headings
- Adult
- Animals
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/microbiology
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/microbiology
- Fatty Acids, Volatile/analysis
- Fatty Acids, Volatile/biosynthesis
- Feces/chemistry
- Feces/microbiology
- Female
- Gastrointestinal Microbiome/drug effects
- Gastrointestinal Microbiome/genetics
- Glucagon-Like Peptide 1/metabolism
- Humans
- Hypoglycemic Agents/pharmacology
- Juglandaceae/chemistry
- Juglandaceae/microbiology
- Male
- Metabolomics
- Metagenome
- Plant Leaves/chemistry
- Plants, Medicinal/chemistry
- Polysaccharides/pharmacology
- Rats, Sprague-Dawley
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Affiliation(s)
- Ye Yao
- Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha,410008, China; Hunan Key Laboratory of Traditional Chinese Medicine for Gan of State Administration, Central South University, Changsha, 410008, China
| | - Lijing Yan
- Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha,410008, China; Hunan Key Laboratory of Traditional Chinese Medicine for Gan of State Administration, Central South University, Changsha, 410008, China
| | - Han Chen
- Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha,410008, China; Hunan Key Laboratory of Traditional Chinese Medicine for Gan of State Administration, Central South University, Changsha, 410008, China
| | - Ning Wu
- Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha,410008, China; Hunan Key Laboratory of Traditional Chinese Medicine for Gan of State Administration, Central South University, Changsha, 410008, China
| | - Wenbo Wang
- Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha,410008, China; Hunan Key Laboratory of Traditional Chinese Medicine for Gan of State Administration, Central South University, Changsha, 410008, China
| | - Dongsheng Wang
- Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha,410008, China; Hunan Key Laboratory of Traditional Chinese Medicine for Gan of State Administration, Central South University, Changsha, 410008, China.
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26
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Flaiz M, Baur T, Brahner S, Poehlein A, Daniel R, Bengelsdorf FR. Caproicibacter fermentans gen. nov., sp. nov., a new caproate-producing bacterium and emended description of the genus Caproiciproducens. Int J Syst Evol Microbiol 2020; 70:4269-4279. [DOI: 10.1099/ijsem.0.004283] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A strictly anaerobic bacterial strain designated EA1T was isolated from an enrichment culture inoculated with biogas reactor content. Cells of strain EA1T are spore-forming rods (1–3×0.4–0.8 µm) and stain Gram-negative, albeit they possess a Gram-positive type of cell-wall ultrastructure. Growth of strain EA1T was observed at 30 and 37 °C and within a pH range of pH 5–9. The major components recovered in the fatty acid fraction were C14:0, C16:0, C16:0 DMA (dimethyl acetal) and C16:1
ω7c. Strain EA1T fermented several mono- and disaccharides. Metabolic end products from fructose were acetate, butyrate, caproate and lactate. Furthermore, ethanol, CO2 and H2 were identified as products. The genome consists of a chromosome (3.9 Mbp) with 3797 predicted protein-encoding genes and a G+C content of 51.25 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain EA1T represents a novel taxon within the family
Oscillospiraceae
. The most closely related type strains of EA1T, based on 16S rRNA gene sequence identity, are
Caproiciproducens galactitolivorans
BS-1T (94.9 %), [
Clostridium
] leptum DSM 753T (93.8 %), [
Clostridium
] sporosphaeroides DSM 1294T (91.7 %) and
Ruminococcus bromii
ATCC 27255T (91.0 %). Further phenotypic characteristics of strain EA1T differentiate it from related, validly described bacterial species. Strain EA1T represents a novel genus and novel species within the family
Oscillospiraceae
. The proposed name is Caproicibacter fermentans gen. nov., sp. nov. The type strain is EA1T (DSM 107079T=JCM 33110T).
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Affiliation(s)
- Maximilian Flaiz
- Institut für Mikrobiologie und Biotechnologie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Tina Baur
- Institut für Mikrobiologie und Biotechnologie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Sven Brahner
- Institut für Mikrobiologie und Biotechnologie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
| | - Frank R. Bengelsdorf
- Institut für Mikrobiologie und Biotechnologie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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27
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Gao Z, Wu Z, Zhang W. Effect of Pit Mud on Bacterial Community and Aroma Components in Yellow Water and Their Changes during the Fermentation of Chinese Strong-Flavor Liquor. Foods 2020; 9:foods9030372. [PMID: 32210161 PMCID: PMC7143002 DOI: 10.3390/foods9030372] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 01/03/2023] Open
Abstract
As the main by-product of Chinese strong-flavor liquor, yellow water plays an important role in the formation of flavor components. Yellow water from different fermentation periods (30th day, 45th day, 60th day) was selected to analyze the aroma components by Headspace solid phase micro-extraction Gas Chromatography–Mass Spectrometry, and the microorganism community was evaluated by high-throughput sequencing technology and bioinformatics analysis of DNA. As the fermentation time was prolonged, the main flavor components significantly increased, and the amount of the common microbial population between yellow water and pit mud increased gradually. Among the common microorganisms, Lactobacillus accounted for the largest proportion, at about 56.96%. The microbes in the yellow water mainly belonged to Firmicutes. The abundance of Bacilli (the main bacteria) gradually decreased with time, at 87.60% at the 30th day down to 68.87% at the 60th day, but Clostridia gradually increased from 10.29% to 27.48%. At the genus level, some microbes increased significantly from the 30th day to 60th day, such as Caproiciproducens, which increased from 2.65% to 6.30%, and Sedimentibacter, increasing from 0.47% to 2.49%. RDA analysis indicated that the main aroma components were positively correlated with Clostridia and negatively correlated with Bacilli.
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Affiliation(s)
- Zhanzheng Gao
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China; (Z.G.); (Z.W.)
- Sichuan Shuijingfang Co., Ltd., Chengdu 610037, China
| | - Zhengyun Wu
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China; (Z.G.); (Z.W.)
| | - Wenxue Zhang
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China; (Z.G.); (Z.W.)
- Correspondence: ; Tel.: +86-028-8540-1785; Fax: +86-028-3760-0278
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28
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Han W, He P, Shao L, Lü F. Road to full bioconversion of biowaste to biochemicals centering on chain elongation: A mini review. J Environ Sci (China) 2019; 86:50-64. [PMID: 31787190 DOI: 10.1016/j.jes.2019.05.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 06/10/2023]
Abstract
Production of biochemicals from waste streams has been attracting increasing worldwide interest to achieve climate protection goals. Chain elongation (CE) for production of medium-chain carboxylic acids (MCCAs, especially caproate, enanthate and caprylate) from diverse biowaste has emerged as a potential economic and environmental technology for a sustainable society. The present mini review summarizes the research utilizing various synthetic or real waste-derived substrates available for MCCA production. Additionally, the microbial characteristics of the CE process are surveyed and discussed. Considering that a large proportion of recalcitrantly biodegradable biowaste and residues cannot be further utilized by CE systems and remain to be treated and disposed, we propose here a loop concept of bioconversion of biowaste to MCCAs making full use of the biowaste with zero emission. This could make possible an alternative technology for synthesis of value-added products from a wide range of biowaste, or even non-biodegradable waste (such as, plastics and rubbers). Meanwhile, the remaining scientific questions, unsolved problems, application potential and possible developments for this technology are discussed.
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Affiliation(s)
- Wenhao Han
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Pinjing He
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of China (MOHURD), China
| | - Liming Shao
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of China (MOHURD), China
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China.
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29
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Lambrecht J, Cichocki N, Schattenberg F, Kleinsteuber S, Harms H, Müller S, Sträuber H. Key sub-community dynamics of medium-chain carboxylate production. Microb Cell Fact 2019; 18:92. [PMID: 31138218 PMCID: PMC6537167 DOI: 10.1186/s12934-019-1143-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/20/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The carboxylate platform is a promising technology for substituting petrochemicals in the provision of specific platform chemicals and liquid fuels. It includes the chain elongation process that exploits reverse β-oxidation to elongate short-chain fatty acids and forms the more valuable medium-chain variants. The pH value influences this process through multiple mechanisms and is central to effective product formation. Its influence on the microbiome dynamics was investigated during anaerobic fermentation of maize silage by combining flow cytometric short interval monitoring, cell sorting and 16S rRNA gene amplicon sequencing. RESULTS Caproate and caprylate titres of up to 6.12 g L-1 and 1.83 g L-1, respectively, were achieved in a continuous stirred-tank reactor operated for 241 days. Caproate production was optimal at pH 5.5 and connected to lactate-based chain elongation, while caprylate production was optimal at pH 6.25 and linked to ethanol utilisation. Flow cytometry recorded 31 sub-communities with cell abundances varying over 89 time points. It revealed a highly dynamic community, whereas the sequencing analysis displayed a mostly unchanged core community. Eight key sub-communities were linked to caproate or caprylate production (rS > | ± 0.7|). Amongst other insights, sorting and subsequently sequencing these sub-communities revealed the central role of Bifidobacterium and Olsenella, two genera of lactic acid bacteria that drove chain elongation by providing additional lactate, serving as electron donor. CONCLUSIONS High-titre medium-chain fatty acid production in a well-established reactor design is possible using complex substrate without the addition of external electron donors. This will greatly ease scaling and profitable implementation of the process. The pH value influenced the substrate utilisation and product spectrum by shaping the microbial community. Flow cytometric single cell analysis enabled fast, short interval analysis of this community and was coupled with 16S rRNA gene amplicon sequencing to reveal the major role of lactate-producing bacteria.
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Affiliation(s)
- Johannes Lambrecht
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318, Leipzig, Germany
| | - Nicolas Cichocki
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318, Leipzig, Germany
| | - Florian Schattenberg
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318, Leipzig, Germany
| | - Sabine Kleinsteuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318, Leipzig, Germany
| | - Hauke Harms
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318, Leipzig, Germany
| | - Susann Müller
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318, Leipzig, Germany.
| | - Heike Sträuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318, Leipzig, Germany
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30
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Wu Q, Bao X, Guo W, Wang B, Li Y, Luo H, Wang H, Ren N. Medium chain carboxylic acids production from waste biomass: Current advances and perspectives. Biotechnol Adv 2019; 37:599-615. [PMID: 30849433 DOI: 10.1016/j.biotechadv.2019.03.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 03/01/2019] [Accepted: 03/03/2019] [Indexed: 11/29/2022]
Abstract
Alternative chemicals to diverse fossil-fuel-based products is urgently needed to mitigate the adverse impacts of fossil fuel depletion on human development. To this end, researchers have focused on the production of biochemical from readily available and affordable waste biomass. This is consistent with current guidelines for sustainable development and provides great advantages related to economy and environment. The search for suitable biochemical products is in progress worldwide. Therefore, this review recommends a biochemical (i.e., medium chain carboxylic acids (MCCAs)) utilizing an emerging biotechnological production platform called the chain elongation (CE) process. This work covers comprehensive introduction of the CE mechanism, functional microbes, available feedstock types and corresponding utilization strategies, major methods to enhance the performance of MCCAs production, and the challenges that need to be addressed for practical application. This work is expected to provide a thorough understanding of the CE technology, to guide and inspire researchers to solve existing problems in depth, and motivate large-scale MCCAs production.
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Affiliation(s)
- Qinglian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Xian Bao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
| | - Bing Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Yunxi Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Haichao Luo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Huazhe Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
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31
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De Groof V, Coma M, Arnot T, Leak DJ, Lanham AB. Medium Chain Carboxylic Acids from Complex Organic Feedstocks by Mixed Culture Fermentation. Molecules 2019; 24:E398. [PMID: 30678297 PMCID: PMC6384945 DOI: 10.3390/molecules24030398] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/10/2019] [Accepted: 01/18/2019] [Indexed: 12/22/2022] Open
Abstract
Environmental pressures caused by population growth and consumerism require the development of resource recovery from waste, hence a circular economy approach. The production of chemicals and fuels from organic waste using mixed microbial cultures (MMC) has become promising. MMC use the synergy of bio-catalytic activities from different microorganisms to transform complex organic feedstock, such as by-products from food production and food waste. In the absence of oxygen, the feedstock can be converted into biogas through the established anaerobic digestion (AD) approach. The potential of MMC has shifted to production of intermediate AD compounds as precursors for renewable chemicals. A particular set of anaerobic pathways in MMC fermentation, known as chain elongation, can occur under specific conditions producing medium chain carboxylic acids (MCCAs) with higher value than biogas and broader applicability. This review introduces the chain elongation pathway and other bio-reactions occurring during MMC fermentation. We present an overview of the complex feedstocks used, and pinpoint the main operational parameters for MCCAs production such as temperature, pH, loading rates, inoculum, head space composition, and reactor design. The review evaluates the key findings of MCCA production using MMC, and concludes by identifying critical research targets to drive forward this promising technology as a valorisation method for complex organic waste.
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Affiliation(s)
- Vicky De Groof
- EPSRC Centre for Doctoral Training in Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Marta Coma
- Centre for Sustainable Chemical Technologies (CSCT), University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Tom Arnot
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Water Innovation & Research Centre (WIRC), University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - David J Leak
- Centre for Sustainable Chemical Technologies (CSCT), University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Ana B Lanham
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Water Innovation & Research Centre (WIRC), University of Bath, Claverton Down, Bath BA2 7AY, UK.
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32
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Wang H, Li X, Wang Y, Tao Y, Lu S, Zhu X, Li D. Improvement of n-caproic acid production with Ruminococcaceae bacterium CPB6: selection of electron acceptors and carbon sources and optimization of the culture medium. Microb Cell Fact 2018; 17:99. [PMID: 29940966 PMCID: PMC6019802 DOI: 10.1186/s12934-018-0946-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/16/2018] [Indexed: 12/02/2022] Open
Abstract
Background Global energy and resource shortages make it necessary to quest for renewable resources. n-Caproic acid (CA) production based on carboxylate platform by anaerobic fermentation is booming. Recently, a novel Ruminococcaceae bacterium CPB6 is shown to be a potential biotransformation factory for CA production from lactate-containing wastewater. However, little is known about the effects of different electron acceptors (EAs) on the fermentative products of strain CPB6, as well as the optimum medium for CA production. Results In this study, batch experiments were performed to investigate the fermentative products of strain CPB6 in a lactate medium supplemented with different EAs and sugars. Supplementation of acetate, butyrate and sucrose dramatically increased cell growth and CA production. The addition of propionate or pentanoate resulted in the production of C5 or C7 carboxylic acid, respectively. Further, a Box–Behnken experiment was conducted to optimize the culture medium for CA production. The result indicated that a medium containing 13.30 g/L sucrose, 22.35 g/L lactate and 16.48 g/L butyrate supported high-titer CA production (16.73 g/L) with a maximum productivity of 6.50 g/L/day. Conclusions This study demonstrated that strain CPB6 could produce C6–C7 carboxylic acids from lactate (as electron donor) with C2–C5 short-chain carboxylic acids (as EAs), but CA (C6 carboxylic acid) was the most major and potential product. Butyrate and sucrose were the most significant EA and carbon source respectively for CA production from lactate by strain CPB6. High titer of CA can be produced from a synthetic substrate containing sucrose, lactate and butyrate. The work provided significant implications for improving CA production in industry-scale.![]() Electronic supplementary material The online version of this article (10.1186/s12934-018-0946-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Han Wang
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xiangzhen Li
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Yong Tao
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China. .,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
| | - Shaowen Lu
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Xiaoyu Zhu
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Daping Li
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
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