1
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Zheng L, Zhang M, Zhao W. Enhanced mycelium biomass and polysaccharide production in genetically modified Pleurotus ostreatus using agricultural wastes. Int J Biol Macromol 2024; 278:134318. [PMID: 39111500 DOI: 10.1016/j.ijbiomac.2024.134318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 07/11/2024] [Accepted: 07/28/2024] [Indexed: 08/18/2024]
Abstract
Edible fungi, healthier for humans and sustainable for the planet, attract unprecedented attention. In the study, the genetically modified Pleurotus ostreatus overexpression phosphoglucomutase (PGM) was constructed. P. ostreatus overexpression PGM (Po::PGM) had 4.96-folds higher expression level of PGM. Po::PGM grew thicker mycelium and more mycelium branches. Additional Ca2+ can inhibit mycelium growth, and cyclic adenosine monophosphate completely inhibited their growth of Po::PGM. Secondly, Overexpression of PGM made P. ostreatus become more sensitive to cell wall disruptors, and caused 12.75 % reduction of β-1, 3-glucan and 40.53 % increase of chitin in cell wall. In submerged fermentation, the mycelia biomass yield and endopolysaccharide (IPS) production of Po::PGM in basic PDB can reach 11.18 g/l and 2.55 g/l, increasing by 20.86 % and 28.79 %, respectively. Whereas exopolysaccharide (EPS) reduced by 3.28 %. After replacing potato and glucose in PDB by wheat bran, mycelia biomass and EPS production of Po::PGM were all improved. The additional lactose in wheat bran did not only furtherly enhance mycelia biomass yield of Po::PGM to 27.78 g/l by 199.03 %, but IPS production also increased by 277.99 % to 6.07 g/l. The results provided us key ideas and important research directions that at least manipulating the PGM gene could obtain high-efficient use of agricultural wastes producing more fungus-based foods.
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Affiliation(s)
- Libing Zheng
- School of Food and Technology, Jiangnan University, Wuxi 214122, China; Institute of Future Food Technology, JITRI, Yixing 214200, China
| | - Mengqing Zhang
- School of Food and Technology, Jiangnan University, Wuxi 214122, China; Institute of Future Food Technology, JITRI, Yixing 214200, China
| | - Wei Zhao
- School of Food and Technology, Jiangnan University, Wuxi 214122, China; Institute of Future Food Technology, JITRI, Yixing 214200, China.
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2
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Wei X, Yang L, Chen Z, Xia W, Chen Y, Cao M, He N. Molecular weight control of poly-γ-glutamic acid reveals novel insights into extracellular polymeric substance synthesis in Bacillus licheniformis. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:60. [PMID: 38711141 DOI: 10.1186/s13068-024-02501-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/04/2024] [Indexed: 05/08/2024]
Abstract
BACKGROUND The structural diversity of extracellular polymeric substances produced by microorganisms is attracting particular attention. Poly-gamma-glutamic acid (γ-PGA) is a widely studied extracellular polymeric substance from Bacillus species. The function of γ-PGA varies with its molecular weight (Mw). RESULTS Herein, different endogenous promoters in Bacillus licheniformis were selected to regulate the expression levels of pgdS, resulting in the formation of γ-PGA with Mw values ranging from 1.61 × 103 to 2.03 × 104 kDa. The yields of γ-PGA and exopolysaccharides (EPS) both increased in the pgdS engineered strain with the lowest Mw and viscosity, in which the EPS content was almost tenfold higher than that of the wild-type strain. Subsequently, the compositions of EPS from the pgdS engineered strain also changed. Metabolomics and RT-qPCR further revealed that improving the transportation efficiency of EPS and the regulation of carbon flow of monosaccharide synthesis could affect the EPS yield. CONCLUSIONS Here, we present a novel insight that increased pgdS expression led to the degradation of γ-PGA Mw and changes in EPS composition, thereby stimulating EPS and γ-PGA production. The results indicated a close relationship between γ-PGA and EPS in B. licheniformis and provided an effective strategy for the controlled synthesis of extracellular polymeric substances.
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Affiliation(s)
- Xiaoyu Wei
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Zhen Chen
- College of Life Science, Xinyang Normal University, Xinyang, 464000, China.
| | - Wenhao Xia
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Yongbin Chen
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China.
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China.
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China.
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3
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Gan L, Huang X, He Z, He T. Exopolysaccharide production by salt-tolerant bacteria: Recent advances, current challenges, and future prospects. Int J Biol Macromol 2024; 264:130731. [PMID: 38471615 DOI: 10.1016/j.ijbiomac.2024.130731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/27/2024] [Accepted: 03/06/2024] [Indexed: 03/14/2024]
Abstract
Natural biopolymers derived from exopolysaccharides (EPSs) are considered eco-friendly and sustainable alternatives to available traditional synthetic counterparts. Salt-tolerant bacteria inhabiting harsh ecological niches have evolved a number of unique adaptation strategies allowing them to maintain cellular integrity and assuring their long-term survival; among these, producing EPSs can be adopted as an effective strategy to thrive under high-salt conditions. A great diversity of EPSs from salt-tolerant bacteria have attracted widespread attention recently. Because of factors such as their unique structural, physicochemical, and functional characteristics, EPSs are commercially valuable for the global market and their application potential in various sectors is promising. However, large-scale production and industrial development of these biopolymers are hindered by their low yields and high costs. Consequently, the research progress and future prospects of salt-tolerant bacterial EPSs must be systematically reviewed to further promote their application and commercialization. In this review, the structure and properties of EPSs produced by a variety of salt-tolerant bacterial strains isolated from different sources are summarized. Further, feasible strategies for solving production bottlenecks are discussed, which provides a scientific basis and direct reference for more scientific and rational EPS development.
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Affiliation(s)
- Longzhan Gan
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China.
| | - Xin Huang
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China
| | - Zhicheng He
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China
| | - Tengxia He
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China.
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4
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Wei X, Chen Z, Liu A, Yang L, Xu Y, Cao M, He N. Advanced strategies for metabolic engineering of Bacillus to produce extracellular polymeric substances. Biotechnol Adv 2023; 67:108199. [PMID: 37330153 DOI: 10.1016/j.biotechadv.2023.108199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/24/2023] [Accepted: 06/11/2023] [Indexed: 06/19/2023]
Abstract
Extracellular polymeric substances are mainly synthesized via a variety of biosynthetic pathways in bacteria. Bacilli-sourced extracellular polymeric substances, such as exopolysaccharides (EPS) and poly-γ-glutamic acid (γ-PGA), can serve as active ingredients and hydrogels, and have other important industrial applications. However, the functional diversity and widespread applications of these extracellular polymeric substances, are hampered by their low yields and high costs. Biosynthesis of extracellular polymeric substances is very complex in Bacillus, and there is no detailed elucidation of the reactions and regulations among various metabolic pathways. Therefore, a better understanding of the metabolic mechanisms is required to broaden the functions and increase the yield of extracellular polymeric substances. This review systematically summarizes the biosynthesis and metabolic mechanisms of extracellular polymeric substances in Bacillus, providing an in-depth understanding of the relationships between EPS and γ-PGA synthesis. This review provides a better clarification of Bacillus metabolic mechanisms during extracellular polymeric substance secretion and thus benefits their application and commercialization.
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Affiliation(s)
- Xiaoyu Wei
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Zhen Chen
- College of Life Science, Xinyang Normal University, Xinyang 464000, China.
| | - Ailing Liu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China; Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361005, China.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China.
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5
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Li C, Li P, Fu H, Chen J, Ye M, Zhai S, Hu F, Zhang C, Ge Y, Fortin C. A comparative study of the accumulation and detoxification of copper and zinc in Chlamydomonas reinhardtii: The role of extracellular polymeric substances. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 871:161995. [PMID: 36739008 DOI: 10.1016/j.scitotenv.2023.161995] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/28/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Extracellular polymeric substances (EPS) form an interface between microalgae and the surrounding water environment. Copper (Cu) and zinc (Zn) are essential micronutrients but may negatively affect microbial growth when their concentrations reach toxic thresholds. However, how EPS affect the accumulation and resistance of Cu and Zn in microalgae remains largely unknown. Here, we investigated EPS production upon Cu/Zn exposure and compared the tolerance strategies to the two metals by Chlamydomonas reinhardtii with and without EPS. Microalgal EPS synthesis was induced by Cu/Zn treatments, and the functional groups of polysaccharides and proteins were involved in complexation with metal ions. The extraction of EPS aggravated the toxicity and reduced the removal of metals from solution, but the effect was more pronounced for Cu than for Zn. Copper bound on the cell surface accounted for 54.6 ± 2.0 % of the Cu accumulated by C. reinhardtii, whose EPS components strongly correlated with Cu adsorption. In contrast, 74.3 ± 3.0 % of accumulated Zn was absorbed in cells, and glutathione synthesis was significantly induced. Redundancy and linear correlation analyses showed that the polysaccharide, protein and DNA contents in EPS were significantly correlated with Cu accumulation, absorption and adsorption but not with Zn. Data fitted to a Michaelis-Menten model further showed that the EPS-intact cells had higher binding capacity for Cu2+ but not for Zn2+. These differential impacts of EPS on Cu/Zn sorption and detoxification contribute to a more comprehensive understanding of the roles of microalgal EPS in the biogeochemical cycle of metals.
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Affiliation(s)
- Chonghua Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Peihuan Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Hongxuan Fu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jiale Chen
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Menglei Ye
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Suhua Zhai
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Fan Hu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Chunhua Zhang
- Demonstration Laboratory of Element and Life Science Research, Laboratory Centre of Life Science, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Ying Ge
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
| | - Claude Fortin
- EcotoQ, Institut National de la Recherche Scientifique, Centre Eau Terre Environnement, 490 de la Couronne, Québec, QC G1K 9A9, Canada
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6
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Wu J, Chen Y, Xu X, Ren W, Zhang X, Cai X, Huang A, Zeng Y, Long H, Xie Z. Screening of bioflocculant and cellulase-producing bacteria strains for biofloc culture systems with fiber-rich carbon source. Front Microbiol 2022; 13:969664. [PMID: 36504821 PMCID: PMC9729547 DOI: 10.3389/fmicb.2022.969664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/31/2022] [Indexed: 11/25/2022] Open
Abstract
The biofloc technology (BFT) system has been widely applied in the shrimp and fish culture industry for its advantages in water-saving, growth improvement, and water quality purification. However, The BFT system usually takes a long time to establish, and the extra carbon source input increases the maintenance cost of the system. In this study, we aimed to develop a low-cost and high-efficient BFT system for Litopenaeus vannamei by applying bacteria that could promote the formation of BFT and utilize cheap carbon sources. Three bioflocculant-producing bacteria strains (M13, M15, and M17) have been screened from a cellulolytic strain collection. All three strains have been identified as Bacillus spp. and can use sugarcane bagasse (SB) as a carbon source, which is a cheap byproduct of the sucrose industry in the tropic area of China. Compared to sucrose, the addition of SB and the three strains could improve the biofloc formation rate, biofloc size distribution, ammonia removal rate, and the growth performance of the shrimps. These results suggest that the bioflocculant and cellulase-producing bacteria strains could promote the biofloc formation and the growth of shrimps by using SB as an economic substitute carbon source in the BFT shrimp culture system.
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Affiliation(s)
- Jinping Wu
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China
| | - Yifeng Chen
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China
| | - Xueni Xu
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China
| | - Wei Ren
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China,State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan, China,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, Hainan, China
| | - Xiang Zhang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China,State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan, China,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, Hainan, China
| | - Xiaoni Cai
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China,State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan, China,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, Hainan, China
| | - Aiyou Huang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China,State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan, China,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, Hainan, China
| | - Yanhua Zeng
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan, China,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, Hainan, China
| | - Hao Long
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan, China,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, Hainan, China,*Correspondence: Hao Long, ; Zhenyu Xie,
| | - Zhenyu Xie
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, Hainan, China,College of Marine Sciences, Hainan University, Haikou, Hainan, China,State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan, China,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, Hainan, China,*Correspondence: Hao Long, ; Zhenyu Xie,
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7
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Wei X, Yang L, Wang H, Chen Z, Xu Y, Weng Y, Cao M, Li Q, He N. Genomic and metabolomic analysis of Bacillus licheniformis with enhanced poly-γ-glutamic acid production through atmospheric and room temperature plasma mutagenesis. Front Chem Sci Eng 2022. [DOI: 10.1007/s11705-022-2211-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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8
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Xia Y, Jiang X, Wang Y, Huang Q, Chen D, Hou C, Mu Y, Shen J. Enhanced anaerobic reduction of nitrobenzene at high salinity by betaine acting as osmoprotectant and regulator of metabolism. WATER RESEARCH 2022; 223:118982. [PMID: 36058098 DOI: 10.1016/j.watres.2022.118982] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/24/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
Anaerobic technology is extensively applied in the treatment of industrial organic wastewater, but high salinity always triggers microbial cell dehydration, causing the failure of the anaerobic process. In this work, betaine, one kind of compatible solutes which could balance the osmotic pressure of anaerobic biomass, was exogenously added for enhancing the anaerobic reduction of nitrobenzene (NB) at high salinity. Only 100 mg L-1 betaine dosing could significantly promote the removal efficiency of NB within 35 h at 9% salinity (36.92 ± 4.02% without betaine and 72.94 ± 6.57% with betaine). The relieving effects on salt stress could be observed in the promotion of more extracellular polymeric substances (EPS) secretion with betaine addition. Additionally, the oxidation-reduction potential (ORP), as well as the electron transfer system (ETS) value, was increased with betaine addition, which was reflected in the improvement of system removal efficiency and enzyme activity. Microbial community analysis demonstrated that Bacillus and Clostridiisalibacter which were positively correlated with the stability of the anaerobic process were enriched with betaine addition at high salinity. Metagenomic analysis speculated that the encoding genes for salt tolerance (kdpB/oadA/betA/opuD/epsP/epsH) and NB degradation (nfsA/wrbA/ccdA/menC) obtained higher relative abundance with betaine addition under high salt environment, which might be the key to improving salt tolerance of anaerobic biomass. The long-term assessment demonstrated that exogenous addition betaine played an important role in maintaining the stability of the anaerobic system, which would be a potential strategy to achieve a high-efficiency anaerobic process under high salinity conditions.
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Affiliation(s)
- Yan Xia
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Xinbai Jiang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Yuxuan Wang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Qian Huang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Dan Chen
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Cheng Hou
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yang Mu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Jinyou Shen
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
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9
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Xu Y, Yang L, Wang H, Wei X, Shi Y, Liang D, Cao M, He N. Putative functions of EpsK in teichuronic acid synthesis and phosphate starvation in Bacillus licheniformis. Synth Syst Biotechnol 2022; 7:815-823. [PMID: 35475252 PMCID: PMC9018123 DOI: 10.1016/j.synbio.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 11/28/2022] Open
Abstract
Extracellular polymeric substances (EPSs) are extracellular macromolecules in bacteria, which function in cell growth and show potential for mechanism study and biosynthesis application. However, the biosynthesis mechanism of EPS is still not clear. We herein chose Bacillus licheniformis CGMCC 2876 as a target strain to investigate the EPS biosynthesis. epsK, a member of eps cluster, the predicted polysaccharide synthesis cluster, was overexpressed and showed that the overexpression of epsK led to a 26.54% decrease in the production of EPS and resulted in slenderer cell shape. Transcriptome analysis combined with protein-protein interactions analysis and protein modeling revealed that epsK was likely responsible for the synthesis of teichuronic acid, a substitute cell wall component of teichoic acid when the strain was suffering phosphate limitation. Further cell cultivation showed that either phosphate limitation or the overexpression of teichuronic acid synthesis genes, tuaB and tuaE could similarly lead to EPS reduction. The enhanced production of teichuronic acid induced by epsK overexpression triggered the endogenous phosphate starvation, resulting in the decreased EPS synthesis and biomass, and the enhanced bacterial chemotaxis. This study presents an insight into the mechanism of EPS synthesis and offers the potential in controllable synthesis of target products.
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Affiliation(s)
- Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Haiyan Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Xiaoyu Wei
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Yanyan Shi
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Dafeng Liang
- Institute of Bioengineering, Guangdong Academy of Sciences, Guangzhou, 510316, Guangdong, PR China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
- Corresponding author. Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
- Corresponding author. Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China.
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10
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Zhang J, Zhu B, Li X, Xu X, Li D, Zeng F, Zhou C, Liu Y, Li Y, Lu F. Multiple Modular Engineering of Bacillus Amyloliquefaciens Cell Factories for Enhanced Production of Alkaline Proteases From B. Clausii. Front Bioeng Biotechnol 2022; 10:866066. [PMID: 35497355 PMCID: PMC9046661 DOI: 10.3389/fbioe.2022.866066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/29/2022] [Indexed: 11/13/2022] Open
Abstract
Bacillus amyloliquefaciens is a generally recognized as safe (GRAS) microorganism that presents great potential for the production of heterologous proteins. In this study, we performed genomic and comparative transcriptome to investigate the critical modular in B. amyloliquefaciens on the production of heterologous alkaline proteases (AprE). After investigation, it was concluded that the key modules affecting the production of alkaline protease were the sporulation germination module (Module I), extracellular protease synthesis module (Module II), and extracellular polysaccharide synthesis module (Module III) in B. amyloliquefaciens. In Module I, AprE yield for mutant BA ΔsigF was 25.3% greater than that of BA Δupp. Combining Module I synergistically with mutation of extracellular proteases in Module II significantly increased AprE production by 36.1% compared with production by BA Δupp. In Module III, the mutation of genes controlling extracellular polysaccharides reduced the viscosity and the accumulation of sediment, and increased the rate of dissolved oxygen in fermentation. Moreover, AprE production was 39.6% higher than in BA Δupp when Modules I, II and III were engineered in combination. This study provides modular engineering strategies for the modification of B. amyloliquefaciens for the production of alkaline proteases.
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Affiliation(s)
- Jinfang Zhang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Baoyue Zhu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Xinyue Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Xiaojian Xu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Dengke Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Fang Zeng
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Cuixia Zhou
- School of Biology and Brewing Engineering, Taishan University, Taian, China
| | - Yihan Liu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Yu Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Fuping Lu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, the College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
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Isolation, Identification and Characterization of Bioflocculant-Producing Bacteria from Activated Sludge of Vulindlela Wastewater Treatment Plant. Appl Microbiol 2021. [DOI: 10.3390/applmicrobiol1030038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The low microbial flocculant yields and efficiencies limit their industrial applications. There is a need to identify bacteria with high bioflocculant production. The aim of this study was to isolate and identify a bioflocculant-producing bacterium from activated sludge wastewater and characterise its bioflocculant activity. The identification of the isolated bacterium was performed by 16S rRNA gene sequencing analysis. The optimal medium composition (carbon and nitrogen sources, cations and inoculum size) and culture conditions (temperature, pH, shaking speed and time) were evaluated by the one-factor-at-a-time method. The morphology, functional groups, crystallinity and pyrolysis profile of the bioflocculant were analysed using scanning electron microscope (SEM), Fourier transform infrared (FTIR) and thermogravimetric (TGA) analysis. The bacterium was identified as Proteus mirabilis AB 932526.1. Its optimal medium and culture conditions were: sucrose (20 g/L), yeast extract (1.2 g/L), MnCl2 (1 g/L), pH 6, 30 °C, inoculation volume (3%), shaking speed (120 rpm) for 72 h of cultivation. SEM micrograph revealed the bioflocculant to be amorphous. FTIR analysis indicated the presence of hydroxyl, carboxyl and amino groups. The bioflocculant was completely pyrolyzed at temperatures above 800 °C. The bacterium has potential to produce bioflocculant of industrial importance.
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12
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Han Q, Yan X, Zhang R, Wang G, Zhang Y. Juglone Inactivates Pseudomonas aeruginosa through Cell Membrane Damage, Biofilm Blockage, and Inhibition of Gene Expression. Molecules 2021; 26:molecules26195854. [PMID: 34641398 PMCID: PMC8510502 DOI: 10.3390/molecules26195854] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
Due to the strong drug resistance of Pseudomonas aeruginosa (P. aeruginosa), the inhibition effects of conventional disinfectants and antibiotics are not obvious. Juglone extracted from discarded walnut husk, as a kind of plant-derived antimicrobial agent, has the advantages of naturalness, high efficiency, and low residue, with a potential role in the inhibition of P. aeruginosa. This study elucidated the inhibitory effect of juglone on the growth of plankton and the formation of P. aeruginosa biofilm. The results showed that juglone (35 μg/mL) had an irreversible inhibitory effect on P. aeruginosa colony formation (about 107 CFU/mL). The integrity and permeability of the cell membrane were effectively destroyed, accompanied by disorder of the membrane permeability, mass leakage of the cytoplasm, and ATP consumption. Further studies manifested that juglone could induce the abnormal accumulation of ROS in cells and block the formation of the cell membrane. In addition, RT-qPCR showed that juglone could effectively block the expression of five virulence genes and two genes involved in the production of extracellular polymers, thereby reducing the toxicity and infection of P. aeruginosa and preventing the production of extracellular polymers. This study can provide support for the innovation of antibacterial technology toward P. aeruginosa in food.
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Affiliation(s)
| | | | | | - Guoliang Wang
- Correspondence: (G.W.); (Y.Z.); Tel.: +86-138-1830-0608 (Y.Z.)
| | - Youlin Zhang
- Correspondence: (G.W.); (Y.Z.); Tel.: +86-138-1830-0608 (Y.Z.)
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13
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Quach NT, Vu THN, Nguyen NA, Nguyen VT, Bui TL, Ky SC, Le TL, Hoang H, Ngo CC, Le TTM, Nguyen TN, Chu HH, Phi QT. Phenotypic features and analysis of genes supporting probiotic action unravel underlying perspectives of Bacillus velezensis VTX9 as a potential feed additive for swine. ANN MICROBIOL 2021. [DOI: 10.1186/s13213-021-01646-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Abstract
Purpose
To date, a total of 13 probiotic Bacillus species are considered as a Generally Recognized as Safe organism (GRAS) approved by the US Federal Food, Drug, and Cosmetic Act (FDCA), which are used for food and feed additives. However, Bacillus velezensis is not considered as a probiotic candidate in swine farming due to a lack of genetic basis of probiotic action-related traits. Therefore, the present study was undertaken to exploit the genetic basis underlying the probiotic traits of B. velezensis VTX9.
Methods
The genome sequencing of B. velezensis VTX9 was performed on a PacBio Sequel platform. The probiotic properties including biosafety, antioxidative capacity, and riboflavin and exopolysaccharide production were evaluated by using genotypic and phenotypic analysis. The secondary metabolite potentials were also predicted.
Results
Strain VTX9 isolated from swine feces proved some probiotic properties including resistance to 3 mM H2O2, 0.6 mM bile salt, low pH, and antipathogenic activity. The complete genome of B. velezensis VTX9 consists of a 3,985,800 bp chromosome that housed 3736 protein-coding genes and 5 plasmids with the size ranging from 7261 to 20,007 bp. Genome analysis revealed no functional genes encoding enterotoxins and transferable antibiotic resistance, which confirmed the safety of VTX9. A total of 82 genes involved in gastrointestinal stress tolerance were predicted, which has not been reported previously. The maximum production of riboflavin reached 769 ± 7.5 ng/ml in LB medium after 72 h, which was in agreement with the complete de novo riboflavin biosynthetic pathway exploited for the first time in the B. velezensis genome. Antagonistic activity against pathogenic bacteria was attributed to 10 secondary metabolites clusters. The presence of a large gene cluster involved in biosynthesis of exopolysaccharides underscored further the adhesion and biofilm-forming capabilities of VTX9 in swine intestines.
Conclusion
Our results revealed for the first time that B. velezensis VTX9 has the potential to be a probiotic candidate. The information provided here on the genome of B. velezensis VTX9 opens new opportunities for using B. velezensis as a feed additive for swine farming in the future.
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Liu C, Sun D, Liu J, Zhu J, Liu W. Recent advances and perspectives in efforts to reduce the production and application cost of microbial flocculants. BIORESOUR BIOPROCESS 2021; 8:51. [PMID: 38650196 PMCID: PMC10992557 DOI: 10.1186/s40643-021-00405-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/08/2021] [Indexed: 01/09/2023] Open
Abstract
Microbial flocculants are macromolecular substances produced by microorganisms. Due to its non-toxic, harmless, and biodegradable advantages, microbial flocculants have been widely used in various industrial fields, such as wastewater treatment, microalgae harvest, activated sludge dewatering, heavy metal ion adsorption, and nanoparticle synthesis, especially in the post-treatment process of fermentation with high safety requirement. However, compared with the traditional inorganic flocculants and organic polymeric flocculants, the high production cost is the main bottleneck that restricts the large-scale production and application of microbial flocculants. To reduce the production cost of microbial flocculant, a series of efforts have been carried out and some exciting research progresses have been achieved. This paper summarized the research advances in the last decade, including the screening of high-yield strains and the construction of genetically engineered strains, search of cheap alternative medium, the extraction and preservation methods, microbial flocculants production as an incidental product of other biological processes, combined use of traditional flocculant and microbial flocculant, and the production of microbial flocculant promoted by inducer. Moreover, this paper prospects the future research directions to further reduce the production cost of microbial flocculants, thereby promoting the industrial production and large-scale application of microbial flocculants.
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Affiliation(s)
- Cong Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life Science, Jiangsu Normal University, No.101, Shanghai road, Tongshan New District, Xuzhou, 221116, Jiangsu, China
| | - Di Sun
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life Science, Jiangsu Normal University, No.101, Shanghai road, Tongshan New District, Xuzhou, 221116, Jiangsu, China
| | - Jiawen Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life Science, Jiangsu Normal University, No.101, Shanghai road, Tongshan New District, Xuzhou, 221116, Jiangsu, China
| | - Jingrong Zhu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life Science, Jiangsu Normal University, No.101, Shanghai road, Tongshan New District, Xuzhou, 221116, Jiangsu, China
| | - Weijie Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life Science, Jiangsu Normal University, No.101, Shanghai road, Tongshan New District, Xuzhou, 221116, Jiangsu, China.
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15
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Liu W, Dong Z, Sun D, Dong Q, Wang S, Zhu J, Liu C. Production of bioflocculant using feather waste as nitrogen source and its use in recycling of straw ash-washing wastewater with low-density and high pH property. CHEMOSPHERE 2020; 252:126495. [PMID: 32199160 DOI: 10.1016/j.chemosphere.2020.126495] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 06/10/2023]
Abstract
Straw ash-washing wastewater is generated in the process of straw combustion power generation and potash fertilizer production. The suspended solid particles in straw ash-washing wastewater are hard to be settled down due to its low-density and high pH properties which inhibit the application of traditional chemical flocculants. Bioflocculant has good advantages in flocculating activity, biodegradability and adaptability of wastewater pH fluctuation. However, high production cost limited the large-scale applications of bioflocculant in wastewater treatment. In this study, the feasibility of using feather waste as cheap alternative nitrogen source of alkaliphilic Bacillus agaradhaerens C9 to produce bioflocculant was investigated. The results showed that strain C9 could simultaneously produce keratinase and bioflocculant, and thereby producing bioflocculant (named as BFF) using feather waste as cheap nitrogen source. The optimal fermentation conditions for enzymatic hydrolysis of feather waste and BFF production was 40 g/L feather wastes, 16 g/L glucose, 37 °C and pH 9.5, and the highest yield of 2.5 g/L was obtained. Moreover, BFF was used to flocculate straw ash-washing wastewater which exhibits low-density and high pH properties, and the highest flocculating rate of 93.1% was achieved when 6.0 mg/L BFF was added. This study reported for the first time that feather waste was used as inexpensive alternative nitrogen source for producing bioflocculant which could treat straw ash-washing wastewater, thereby promoting the resourceful utilization of feather waste and the reuse of straw ash-washing wastewater.
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Affiliation(s)
- Weijie Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China
| | - Zhen Dong
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China
| | - Di Sun
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China
| | - Qinxin Dong
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China
| | - Shiwei Wang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xian, 710069, Shaanxi Province, China
| | - Jingrong Zhu
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China
| | - Cong Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
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16
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Wu R, Qin Y, Shen Q, Li P. The complete genome sequence of Bacillus velezensis LPL061, an exopolysaccharide-producing bacterium. 3 Biotech 2020; 10:243. [PMID: 32405447 DOI: 10.1007/s13205-020-02228-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/24/2020] [Indexed: 01/08/2023] Open
Abstract
Bacillus velezensis LPL061, which shows strong exopolysaccharide (EPS) producing capacity, was isolated from carnations in Beijing, China. The complete genome of LPL061 comprised a single circular chromosome (3,907,268 bp; G+C content of 46.7%) with 3,737 coding DNA sequences, 26 rRNA, and 89 tRNA. According to genome analysis, 12 protein-coding genes which related to polysaccharide biosynthesis in LPL061 were identified. Comparative genome analysis revealed that the EPS biosynthetic gene cluster was relatively conserved among Bacillus species. EPS showed approximately 60% inhibitory activity on the α-glucosidase at 100 μg/mL. The results of quantitative reverse transcription PCR further demonstrated that compared to insulin-resistant model with insulin (500 μg/mL) (without EPS treatment), the insulin-resistant HepG2 cells treated with EPS decreased the expression of phosphoenolpyruvate carboxykinase (PEPCK) from 4.425 to 0.1587, glucose-6-phosphatase (G6Pase) decreased from 4.272 to 0.1929, and glycogen synthase kinase3β (GSK(3)β) decreased from 2.451 to 0.993, respectively. Meanwhile, EPS treatment increased GS expression and resulted in intracellular glycogen concentration increased from 28.30% to 86.48%, which further supported that EPS form LPL061 could reduce the concentration of blood glucose effectively. These results could be beneficial for better understanding of the hypoglycemic mechanism of B. velezensis LPL061 EPS and developing an EPS-based anti-diabetic agent in the future.
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Affiliation(s)
- Ruiyun Wu
- 1Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, East Campus, Haidian District, Beijing, 100083 China
| | - Yuxuan Qin
- 3Department of Biology, Northeastern University, Boston, MA 02115 USA
| | - Qian Shen
- 2Department of Microbiology, Ohio State University, Columbus, USA
| | - Pinglan Li
- 1Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, East Campus, Haidian District, Beijing, 100083 China
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Transcriptome analysis of polysaccharide-based microbial flocculant MBFA9 biosynthesis regulated by nitrogen source. Sci Rep 2020; 10:2918. [PMID: 32075995 PMCID: PMC7031244 DOI: 10.1038/s41598-020-59114-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 01/21/2020] [Indexed: 11/09/2022] Open
Abstract
Microbial flocculant (MBF), an environmentally friendly water treatment agent, can be widely used in various water treatments. However, its use is limited by low yield and high cost. This problem can be solved by clarifying its biosynthesis mechanism and regulating it. Paenibacillus shenyangensis A9, a flocculant-producing bacterium, was used to produce polysaccharide-type MBFA9 by regulating the nitrogen source (nitrogen adequacy/nitrogen deficiency). In this study, RNA-Seq high-throughput sequencing technology and bioinformatic approaches were used to investigate the fermentation and biosynthesis of polysaccharide-type MBFA9 by regulating the nitrogen source (high nitrogen/low nitrogen) in the flocculant-producing bacteria Paenibacillus shenyangensis A9. Differentially expressed genes, functional clustering, and functional annotation of key genes were assessed. Then the MBFA9 biosynthesis and metabolic pathway were reconstructed. Our results showed that when cultured under different nitrogen conditions, bacterial strain A9 had a greater ability to synthesize polysaccharide-type MBFA9 under low nitrogen compared to high nitrogen conditions, with the yield of MBFA9 reaching 4.2 g/L at 36 h of cultivation. The quality of transcriptome sequencing data was reliable, with a matching rate of 85.38% and 85.48% when L36/H36 was mapped to the reference genome. The total expressed genes detected were 4719 and 4730, with 265 differentially expressed genes. The differentially expressed genes were classified into 3 categories: molecular function (MF), cell component (CC), and biological process (BP), and can be further divided into 22 subcategories. There were 192 upregulated genes and 73 downregulated genes, with upregulation being predominant under low nitrogen. UDP-Gal, UDP-Glc, UDP-GlcA, and UDP-GlcNAc, which are in the polysaccharide metabolic pathway, could all be used as precursors for MBFA9 biosynthesis, and murA, wecB, pgm, galU/galF, fcl, gmd, and glgC were the main functional genes capable of affecting the growth of bacteria and the biosynthesis of MBF. Results from this study provide evidence that high-level expression of key genes in MBFA9 biosynthesis, regulation, and control can achieve MBFA9 directional synthesis for large-scale applications.
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Unraveling the specific regulation of the shikimate pathway for tyrosine accumulation in Bacillus licheniformis. ACTA ACUST UNITED AC 2019; 46:1047-1059. [DOI: 10.1007/s10295-019-02213-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/04/2019] [Indexed: 12/24/2022]
Abstract
Abstract
l-Tyrosine serves as a common precursor for multiple valuable secondary metabolites. Synthesis of this aromatic amino acid in Bacillus licheniformis occurs via the shikimate pathway, but the underlying mechanisms involving metabolic regulation remain unclear. In this work, improved l-tyrosine accumulation was achieved in B. licheniformis via co-overexpression of aroGfbr and tyrAfbr from Escherichia coli to yield strain 45A12, and the l-tyrosine titer increased to 1005 mg/L with controlled glucose feeding. Quantitative RT-PCR results indicated that aroA, encoding DAHP synthase, and aroK, encoding shikimate kinase, were feedback-repressed by the end product l-tyrosine in the modified strain. Therefore, the native aroK was first expressed with multiple copies to yield strain 45A13, which could accumulate 1201 mg/L l-tyrosine. Compared with strain 45A12, the expression of aroB and aroF in strain 45A13 was upregulated by 21% and 27%, respectively, which may also have resulted in the improvement of l-tyrosine production. Furthermore, supplementation with 5 g/L shikimate enhanced the l-tyrosine titers of 45A12 and 45A13 by 29.1% and 24.0%, respectively. However, the yield of l-tyrosine per unit of shikimate decreased from 0.365 to 0.198 mol/mol after aroK overexpression in strain 45A12, which suggested that the gene product was also involved in uncharacterized pathways. This study provides a good starting point for further modification to achieve industrial-scale production of l-tyrosine using B. licheniformis, a generally recognized as safe workhorse.
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Bisht V, Lal B. Exploration of Performance Kinetics and Mechanism of Action of a Potential Novel Bioflocculant BF-VB2 on Clay and Dye Wastewater Flocculation. Front Microbiol 2019; 10:1288. [PMID: 31231353 PMCID: PMC6568053 DOI: 10.3389/fmicb.2019.01288] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/23/2019] [Indexed: 11/27/2022] Open
Abstract
This study explores production of an efficient bioflocculant; BF-VB2, by strain Bacillus sp. TERI VB2 and proposes its potential application in wastewater treatment. One milligram of BF-VB2 can effectively flocculate 1980.0 mg ± 5.0 mg of kaolin particles leading to 99.0% ± 0.5% enhancement in flocculation activity and 99.6% ± 1.0% reduction in turbidity; in less time. BF-VB2 when applied for treatment of textile dyeing industrial wastewater revealed reduction in dye color (82.78% ± 3.03%), COD (92.54% ± 0.24%), TSS (73.59% ± 0.71%), and chloride ions (81.90% ± 0.716%). The best-fit kinetic model (for both COD removal, and dye decolorization) was pseudo-first order with regression coefficient of 0.98 and 0.95, and rate constant of 4.33 × 10-2 and 1.83 × 102, respectively. Bridging due to presence of surface charges have been proposed as flocculation mechanism. From results obtained during test-tube studies, flocculation in larger volumes (0.01–5.0 L) was also performed to intend taking up BF-VB2 for in situ industrial wastewater treatment. This eco-friendly polysaccharide bioflocculant had longer shelf-life, stability to pH and temperature, cation-independence, and emerged to be more efficient than other flocculants assessed. This study proposed BF-VB2 as a potential natural flocculant candidate for industrial application.
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Affiliation(s)
- Varsha Bisht
- Department of Biotechnology, TERI School of Advanced Studies, New Delhi, India.,Environmental and Industrial Biotechnology Division, The Energy and Resources Institute, India Habitat Center, New Delhi, India
| | - Banwari Lal
- Environmental and Industrial Biotechnology Division, The Energy and Resources Institute, India Habitat Center, New Delhi, India
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20
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Chen M, Tian LL, Ren CY, Xu CY, Wang YY, Li L. Extracellular polysaccharide synthesis in a bloom-forming strain of Microcystis aeruginosa: implications for colonization and buoyancy. Sci Rep 2019; 9:1251. [PMID: 30718739 PMCID: PMC6362013 DOI: 10.1038/s41598-018-37398-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 12/06/2018] [Indexed: 02/07/2023] Open
Abstract
Microcystis, the dominant species among cyanobacterial blooms, normally forms colonies under natural conditions but exists as single cells or paired cells in axenic laboratory cultures after long-term cultivation. Here, a bloom-forming Microcystis aeruginosa strain CHAOHU 1326 was studied because it presents a colonial morphology and grows on the water surface during axenic laboratory culturing. We first examined the morphological features of strain CHAOHU 1326 and three other unicellular M. aeruginosa strains FACHB-925, FACHB-940, and FACHB-975 cultured under the same conditions by scanning and transmission electron microscopy. Then, we compared the extracellular polysaccharide (EPS)-producing ability of colonial strain CHAOHU 1326 to that of the three unicellular M. aeruginosa strains, and found that strain CHAOHU 1326 produced a higher amount of EPS than the other strains during growth. Moreover, based on genome sequencing, multiple gene clusters implicated in EPS biosynthesis and a cluster of 12 genes predicted to be involved in gas vesicle synthesis in strain CHAOHU 1326 were detected. These predicted genes were all functional and expressed in M. aeruginosa CHAOHU 1326 as determined by reverse transcription PCR. These findings provide a physiological and genetic basis to better understand colony formation and buoyancy control during M. aeruginosa blooming.
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Affiliation(s)
- Meng Chen
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Li-Li Tian
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Chong-Yang Ren
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Chun-Yang Xu
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Yi-Ying Wang
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Li Li
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China.
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Salehizadeh H, Yan N, Farnood R. Recent advances in polysaccharide bio-based flocculants. Biotechnol Adv 2017; 36:92-119. [PMID: 28993221 DOI: 10.1016/j.biotechadv.2017.10.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 09/09/2017] [Accepted: 10/05/2017] [Indexed: 01/03/2023]
Abstract
Natural polysaccharides, derived from biomass feedstocks, marine resources, and microorganisms, have been attracting considerable attention as benign and environmentally friendly substitutes for synthetic polymeric products. Besides many other applications, these biopolymers are rapidly emerging as viable alternatives to harmful synthetic flocculating agents for the removal of contaminants from water and wastewater. In recent years, a great deal of effort has been devoted to improve the production and performance of polysaccharide bio-based flocculants. In this review, current trends in preparation and chemical modification of polysaccharide bio-based flocculants and their flocculation performance are discussed. Aspects including mechanisms of flocculation, biosynthesis, classification, purification and characterization, chemical modification, the effect of physicochemical factors on flocculating activity, and recent applications of polysaccharide bio-based flocculants are summarized and presented.
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Affiliation(s)
- Hossein Salehizadeh
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, Ontario M5S 3E5, Canada.
| | - Ning Yan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, Ontario M5S 3E5, Canada; Faculty of Forestry, University of Toronto, 33 Willcocks St., Toronto, Ontario M5S 3B3, Canada.
| | - Ramin Farnood
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, Ontario M5S 3E5, Canada.
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Liu P, Chen Z, Yang L, Li Q, He N. Increasing the bioflocculant production and identifying the effect of overexpressing epsB on the synthesis of polysaccharide and γ-PGA in Bacillus licheniformis. Microb Cell Fact 2017; 16:163. [PMID: 28950882 PMCID: PMC5615475 DOI: 10.1186/s12934-017-0775-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/18/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Polysaccharides and poly-γ-glutamic acid (γ-PGA) are biomacromolecules that have been reported as bioflocculants, and they exhibit high flocculating activity in many industrial applications. Bacillus licheniformis CGMCC 2876 can produce polysaccharide and γ-PGA bioflocculants under different culture conditions. Several key genes are involved in the metabolic pathway of polysaccharides in B. licheniformis, but the impacts of the regulation of these genes on the production of polysaccharide bioflocculants have not been illustrated completely. To increase the bioflocculant production and identify the correlation between the synthesis of polysaccharides and γ-PGA in B. licheniformis, a few key genes were investigated to explore their influence on the synthesis of the bioflocculants. RESULTS Overexpressing epsB from the eps gene cluster not only improved the bioflocculant crude yield by 13.98% but also enhanced the flocculating activity by 117.92%. The composition of the bioflocculant from the epsB recombinant strain was 28.95% total sugar, 3.464% protein and 44.03% γ-PGA, while in the original strain, these components represented 53.67%, 3.246% and 34.13%, respectively. In combination with an analysis of the transcriptional levels of several key genes involved in γ-PGA synthesis in B. licheniformis, we inferred that epsB played a key role in the synthesis of both polysaccharide and γ-PGA. The bioflocculant production of the epsB recombinant strain was further evaluated during batch fermentation in a 2 L fermenter; the flocculating activity reached 9612.75 U/mL, and the bioflocculant yield reached 10.26 g/L after 72 h, representing increases of 224% and 36.62%, respectively, compared with the original strain. Moreover, we found that the tandem expression of phosphoglucomutase (pgcA) and UTP-glucose-1-phosphate uridylyltransferase (gtaB1) could enhance the crude yield of the bioflocculant by 20.77% and that the overexpression of epsA could enhance the bioflocculant yield by 23.70% compared with the original strain. CONCLUSIONS This study provides a new method to greatly increase the bioflocculant production in B. licheniformis, and it demonstrates the correlation between the biosynthesis of polysaccharide and γ-PGA during EPS fermentation by regulating the expression of EpsB.
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Affiliation(s)
- Peize Liu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 People’s Republic of China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005 People’s Republic of China
| | - Zhen Chen
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 People’s Republic of China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005 People’s Republic of China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 People’s Republic of China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005 People’s Republic of China
| | - Qingbiao Li
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 People’s Republic of China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005 People’s Republic of China
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 People’s Republic of China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005 People’s Republic of China
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Yu W, Chen Z, Ye H, Liu P, Li Z, Wang Y, Li Q, Yan S, Zhong CJ, He N. Effect of glucose on poly-γ-glutamic acid metabolism in Bacillus licheniformis. Microb Cell Fact 2017; 16:22. [PMID: 28178965 PMCID: PMC5299652 DOI: 10.1186/s12934-017-0642-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/28/2017] [Indexed: 11/23/2022] Open
Abstract
Background Poly-gamma-glutamic acid (γ-PGA) is a promising macromolecule with potential as a replacement for chemosynthetic polymers. γ-PGA can be produced by many microorganisms, including Bacillus species. Bacillus licheniformis CGMCC2876 secretes γ-PGA when using glycerol and trisodium citrate as its optimal carbon sources and secretes polysaccharides when using glucose as the sole carbon source. To better understand the metabolic mechanism underlying the secretion of polymeric substances, SWATH was applied to investigate the effect of glucose on the production of polysaccharides and γ-PGA at the proteome level. Results The addition of glucose at 5 or 10 g/L of glucose decreased the γ-PGA concentration by 31.54 or 61.62%, respectively, whereas the polysaccharide concentration increased from 5.2 to 43.47%. Several proteins playing related roles in γ-PGA and polysaccharide synthesis were identified using the SWATH acquisition LC–MS/MS method. CcpA and CcpN co-enhanced glycolysis and suppressed carbon flux into the TCA cycle, consequently slowing glutamic acid synthesis. On the other hand, CcpN cut off the carbon flux from glycerol metabolism and further reduced γ-PGA production. CcpA activated a series of operons (glm and epsA-O) to reallocate the carbon flux to polysaccharide synthesis when glucose was present. The production of γ-PGA was influenced by NrgB, which converted the major nitrogen metabolic flux between NH4+ and glutamate. Conclusion The mechanism by which B. licheniformis regulates two macromolecules was proposed for the first time in this paper. This genetic information will facilitate the engineering of bacteria for practicable strategies for the fermentation of γ-PGA and polysaccharides for diverse applications. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0642-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wencheng Yu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.,The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Zhen Chen
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.,The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Hong Ye
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.,The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Peize Liu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.,The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Zhipeng Li
- Fujian Provincial Key Laboratory of Fire Retardant Materials, College of Materials, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Yuanpeng Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.,The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Qingbiao Li
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.,The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Shan Yan
- Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA
| | - Chuan-Jian Zhong
- Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China. .,The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China.
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