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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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Zeng W, Liu Y, Shu L, Guo Y, Wang L, Liang Z. Production of ultra-high-molecular-weight poly-γ-glutamic acid by a newly isolated Bacillus subtilis strain and genomic and transcriptomic analyses. Biotechnol J 2024; 19:e2300614. [PMID: 38581093 DOI: 10.1002/biot.202300614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 03/01/2024] [Accepted: 03/14/2024] [Indexed: 04/08/2024]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a microbial-derived polymer with molecular weight (Mw) from 104 to 107 Da, and the high-Mw (> 7.0 × 105 Da) or ultra-high-Mw (> 5.0 × 106 Da) γ-PGA has important application value as a tissue engineering material, as a flocculant, and as a heavy metal remover. Therefore, how to produce these high-Mw γ-PGAs with low cost and high efficiency has attracted wide attention. In this study, a γ-PGA producer was isolated from the natural environment, and identified and named Bacillus subtilis GXD-20. Then, the ultra-high-Mw (> 6.0 × 106 Da) γ-PGA produced by GXD-20 was characterized. Interestingly, GXD-20 could produce γ-PGA at 42°C, and exhibited a γ-PGA titer of up to 22.29 ± 0.59 g L-1 in a 5-L fermenter after optimization of the fermentation process. Comparative genomic analysis indicated that the specific protein sequence and subcellular localization of PgdS (a γ-PGA-degrading enzyme) were closely related to the ultra-high-Mw of γ-PGA. Transcriptomic analysis revealed that the high γ-PGA titer at 42°C was mainly related to the high expression of genes encoding enzymes for sucrose transportation and utilization, nitrogen transportation, endogenous glutamate synthesis, and γ-PGA synthesis. These results provide new insights into the production of ultra-high-Mw γ-PGA by Bacillus at high temperatures.
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Affiliation(s)
- Wei Zeng
- Key Laboratory of Biochemistry and Molecular Biology (Guilin Medical University), Education Department of Guangxi Zhuang Autonomous Region, School of Intelligent Medicine and Biotechnology, Guilin Medical University, Guilin, Guangxi, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Yuanyuan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Lin Shu
- Key Laboratory of Biochemistry and Molecular Biology (Guilin Medical University), Education Department of Guangxi Zhuang Autonomous Region, School of Intelligent Medicine and Biotechnology, Guilin Medical University, Guilin, Guangxi, China
| | - Yin Guo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Linye Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Zhiqun Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
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3
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Elbanna K, Alsulami FS, Neyaz LA, Abulreesh HH. Poly (γ) glutamic acid: a unique microbial biopolymer with diverse commercial applicability. Front Microbiol 2024; 15:1348411. [PMID: 38414762 PMCID: PMC10897055 DOI: 10.3389/fmicb.2024.1348411] [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: 12/02/2023] [Accepted: 01/19/2024] [Indexed: 02/29/2024] Open
Abstract
Microbial biopolymers have emerged as promising solutions for environmental pollution-related human health issues. Poly-γ-glutamic acid (γ-PGA), a natural anionic polymeric compound, is composed of highly viscous homo-polyamide of D and L-glutamic acid units. The extracellular water solubility of PGA biopolymer facilitates its complete biodegradation and makes it safe for humans. The unique properties have enabled its applications in healthcare, pharmaceuticals, water treatment, foods, and other domains. It is applied as a thickener, taste-masking agent, stabilizer, texture modifier, moisturizer, bitterness-reducing agent, probiotics cryoprotectant, and protein crystallization agent in food industries. γ-PGA is employed as a biological adhesive, drug carrier, and non-viral vector for safe gene delivery in tissue engineering, pharmaceuticals, and medicine. It is also used as a moisturizer to improve the quality of hair care and skincare cosmetic products. In agriculture, it serves as an ideal stabilizer, environment-friendly fertilizer synergist, plant-growth promoter, metal biosorbent in soil washing, and animal feed additive to reduce body fat and enhance egg-shell strength.
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Affiliation(s)
- Khaled Elbanna
- Department of Biology, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
- Research Laboratories Unit, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
- Department of Agricultural Microbiology, Faculty of Agriculture, Fayoum University, Fayoum, Egypt
| | - Fatimah S Alsulami
- Department of Biology, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
- Research Laboratories Unit, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Leena A Neyaz
- Department of Biology, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
- Research Laboratories Unit, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Hussein H Abulreesh
- Department of Biology, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
- Research Laboratories Unit, Faculty of Science, Umm Al-Qura University, Makkah, Saudi Arabia
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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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Oyama H, Nabeshima Y, Morimoto K, Sugimura Y. Characterization of proteinous coagulant in Moringa tree seeds for water purification: Stepwise laboratory exercise for high-school students. BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION : A BIMONTHLY PUBLICATION OF THE INTERNATIONAL UNION OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2023; 51:588-599. [PMID: 37357998 DOI: 10.1002/bmb.21763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 05/29/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023]
Abstract
Coagulation is an important process in the context of water purification; and the seed protein of the moringa tree (Moringa oleifera) is a remarkably effective coagulant. The laboratory course described here is designed to provide high-school students with a stepwise, hands-on experience in investigating the protein-rich coagulant found in Moringa seeds. First, the seed powder was applied to model polluted water containing fine clay, food dyes, copper sulfate, and bacteria. This treatment changed the polluted water into clear water via coagulation; all students were convinced that the coagulation-inducing agent was a thermostable cationic protein. Finally, basic biochemical techniques (e.g., chromatographic separation and electrophoresis) were used to show that the target coagulant is a dimeric protein composed of 6.5 and 4.5 kDa subunits. Overall, this made it possible for the students to gain a deeper understanding (more comprehensive than the information taught in formal classes) of protein structure and its real-world implications. This stepwise exercise can be applied to research-based learning programs in high school, as it is an effective learning tool.
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Affiliation(s)
- Hiroshi Oyama
- Faculty of Science and Engineering, Setsunan University, Neyagawa, Japan
| | - Yuka Nabeshima
- Faculty of Science and Engineering, Setsunan University, Neyagawa, Japan
| | - Koichi Morimoto
- Faculty of Education, Nara University of Education, Nara, Japan
| | - Yukio Sugimura
- School of Science and Technology, Kyoto Institute of Technology, Kyoto, Japan
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Samal S, Banerjee S, Dey P, Rangarajan V. Production and characterization of a novel poly amino acid from a thermophilic bacterium, and preliminary testing of its coagulating potential for imminent wastewater treatment application. Int J Biol Macromol 2023; 246:125589. [PMID: 37385322 DOI: 10.1016/j.ijbiomac.2023.125589] [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: 04/23/2023] [Revised: 06/15/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
The increasing demand for biopolymers across diverse fields, such as food, medicine, cosmetics, and environmental applications, has prompted researchers to explore novel molecules with enhanced functionalities that meet these demands. In this study, a thermophilic strain of Bacillus licheniformis was employed to produce a unique polyamino acid. This thermophilic isolate exhibited rapid growth at 50 °C in a sucrose mineral salts medium, resulting in a biopolymer concentration of 7.4 g/L. Interestingly, the biopolymer produced at different temperatures exhibited varying glass-transition temperatures (ranging from 87.86 °C to 104.11 °C) and viscosities (7.5 cP to 16.3 cP), suggesting that the fermentation temperature significantly influenced the degree of polymerization. Furthermore, the biopolymer was characterized using various techniques, including Thin Layer Chromatography (TLC), Fourier Transform Infrared (FTIR) spectroscopy, Liquid Chromatography-Electrospray Ionization-Mass Spectroscopy (LC-ESI MS), Nuclear Magnetic Resonance (NMR), and Differential Scanning Calorimetry-Thermogravimetric Analysis (DSC-TGA). The results revealed that the obtained biopolymer was a poly amino acid, with poly-γ-glutamic acid as the major monomeric component in the polymer backbone with a few appendages of aspartic acid residues in its side chain. Finally, the biopolymer demonstrated significant coagulation potential for water treatment applications, as evidenced by coagulation studies conducted under varying pH conditions using kaolin-clay as a model precipitant.
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Affiliation(s)
- Subhranshu Samal
- Department of Chemical Engineering, Birla Institute of Technology and Science Pilani K.K. Birla Goa Campus, 403726, India
| | - Subhadeep Banerjee
- Department of Chemistry, Birla Institute of Technology and Science Pilani K.K. Birla Goa Campus, 403726, India
| | - Pinaki Dey
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India
| | - Vivek Rangarajan
- Department of Chemical Engineering, Birla Institute of Technology and Science Pilani K.K. Birla Goa Campus, 403726, India.
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Nair P, Navale GR, Dharne MS. Poly-gamma-glutamic acid biopolymer: a sleeping giant with diverse applications and unique opportunities for commercialization. BIOMASS CONVERSION AND BIOREFINERY 2023; 13:4555-4573. [PMID: 33824848 PMCID: PMC8016157 DOI: 10.1007/s13399-021-01467-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 05/06/2023]
Abstract
Poly-gamma-glutamic acid (γ-PGA) is a biodegradable, non-toxic, ecofriendly, and non-immunogenic biopolymer. Its phenomenal properties have gained immense attention in the field of regenerative medicine, the food industry, wastewater treatment, and even in 3D printing bio-ink. The γ-PGA has the potential to replace synthetic non-degradable counterparts, but the main obstacle is the high production cost and lower productivity. Extensive research has been carried out to reduce the production cost by using different waste; however, it is unable to match the commercialization needs. This review focuses on the biosynthetic mechanism of γ-PGA, its production using the synthetic medium as well as different wastes by L-glutamic acid-dependent and independent microbial strains. Furthermore, various metabolic engineering strategies and the recovery processes for γ-PGA and their possible applications are discussed. Finally, highlights on the challenges and unique approaches to reduce the production cost and to increase the productivity for commercialization of γ-PGA are also summarized.
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Affiliation(s)
- Pranav Nair
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
- National Collection of Industrial Microorganisms (NCIM), CSIR-National Chemical Laboratory, Pune, 411008 India
| | - Govinda R. Navale
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
- National Collection of Industrial Microorganisms (NCIM), CSIR-National Chemical Laboratory, Pune, 411008 India
| | - Mahesh S. Dharne
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
- National Collection of Industrial Microorganisms (NCIM), CSIR-National Chemical Laboratory, Pune, 411008 India
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Parati M, Khalil I, Tchuenbou-Magaia F, Adamus G, Mendrek B, Hill R, Radecka I. Building a circular economy around poly(D/L-γ-glutamic acid)- a smart microbial biopolymer. Biotechnol Adv 2022; 61:108049. [DOI: 10.1016/j.biotechadv.2022.108049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/26/2022]
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Bahniuk MS, Alidina F, Tan X, Unsworth LD. The last 25 years of research on bioflocculants for kaolin flocculation with recent trends and technical challenges for the future. Front Bioeng Biotechnol 2022; 10:1048755. [PMID: 36507274 PMCID: PMC9731118 DOI: 10.3389/fbioe.2022.1048755] [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: 09/19/2022] [Accepted: 11/09/2022] [Indexed: 11/27/2022] Open
Abstract
The generation of kaolin-containing wastewater is an inevitable consequence in a number of industries including mining, wastewater treatment, and bitumen processing. In some cases, the production of kaolin tailings waste during the production of bitumen or phosphate is as high as 3 times greater than the actual produced product. The existing inventory of nearly five billion barrels of oil sands tailings alone represents a massive storage and reclamation challenge, as well as a significant economic and environmental liability. Current reclamation options like inorganic coagulants and organic synthetic polymers may settle kaolin effectively, but may themselves pose an additional environmental hazard. Bioflocculants are an emerging alternative, given the inherent safety and biodegradability of their bio-based compositions. This review summarizes the different research attempts towards a better bioflocculant of kaolin, with a focus on the bioflocculant source, composition, and effective flocculating conditions. Bacillus bacteria were the most prevalent single species for bioflocculant production, with wastewater also hosting a large number of bioflocculant-producing microorganisms while serving as an inexpensive nutrient. Effective kaolin flocculation could be obtained over a broad range of pH values (1-12) and temperatures (5-95°C). Uronic acid and glutamic acid were predominant sugars and amino acids, respectively, in a number of effective bioflocculants, potentially due to their structural and charge similarities to effective synthetic polymers like polyacrylamide. Overall, these results demonstrate that bioflocculants can be produced from a wide range of microorganisms, can be composed of polysaccharides, protein or glycoproteins and can serve as effective treatment options for kaolin. In some cases, the next obstacle to their wide-spread application is scaling to industrially relevant volumes and their deployment strategies.
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Zając E, Fabiańska MJ, Jędrszczyk E, Skalski T. Hydrocarbon Degradation and Microbial Survival Improvement in Response to γ-Polyglutamic Acid Application. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:15066. [PMID: 36429785 PMCID: PMC9690351 DOI: 10.3390/ijerph192215066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/09/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
To improve the environmental sustainability of cleanup activities of contaminated sites there is a need to develop technologies that minimize soil and habitat disturbances. Cleanup technologies, such as bioremediation, are based on biological products and processes, and they are important for the future of our planet. We studied the potential of γ-poly glutamic acid (PGA) as a natural component of biofilm produced by Bacillus sp. to be used for the decomposition of petroleum products, such as heavy naphtha (N), lubricating oil (O), and grease (G). The study aimed to assess the impact of the use of different concentrations of PGA on the degradation process of various fractions of petroleum hydrocarbons (PH) and its effect on bacterial population growth in harsh conditions of PH contamination. In laboratory conditions, four treatments of PGA with each of the petroleum products (N, O, and G) were tested: PGA0 (reference), PGA1 (1% PGA), PGA1B (1% PGA with Bacillus licheniformis), and PGA10 (10% PGA). After 7, 28, 56, and 112 days of the experiment, the percentage yield extraction, hydrocarbon mass loss, geochemical ratios, pH, electrical conductivity, and microorganisms survival were determined. We observed an increase in PH removal, reflected as a higher amount of extraction yield (growing with time and reaching about 11% in G) and loss of hydrocarbon mass (about 4% in O and G) in all treatments of the PGA compared to the reference. The positive degradation impact was intensive until around day 60. The PH removal stimulation by PGA was also reflected by changes in the values of geochemical ratios, which indicated that the highest rate of degradation was at the initial stage of the process. In general, for the stimulation of PH removal, using a lower (1%) concentration of PGA resulted in better performance than a higher concentration (10%). The PH removal facilitated by PGA is related to the anionic homopoliamid structure of the molecule and its action as a surfactant, which leads to the formation of micelles and the gradual release of PH absorbed in the zeolite carrier. Moreover, the protective properties of PGA against the extinction of bacteria under high concentrations of PH were identified. Generally, the γ-PGA biopolymer helps to degrade the hydrocarbon pollutants and stabilize the environment suitable for microbial degraders development.
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Affiliation(s)
- Ewelina Zając
- Department of Land Reclamation and Environmental Development, Faculty of Environmental Engineering and Land Surveying, University of Agriculture in Krakow, Al. Mickiewicza 21, 31-120 Krakow, Poland
| | - Monika J. Fabiańska
- Faculty of Earth Sciences, University of Silesia, 60 Będzińska Street, 41-200 Sosnowiec, Poland
| | - Elżbieta Jędrszczyk
- Department of Vegetable and Medicinal Plants, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, al. 29 Listopada 45, 31-425 Krakow, Poland
| | - Tomasz Skalski
- Tunneling Group, Biotechnology Centre, Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland
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Effect of Bacillus subtilis Zeolite Used for Sediment Remediation on Sulfide, Phosphate, and Nitrogen Control in a Microcosm. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19074163. [PMID: 35409843 PMCID: PMC8998431 DOI: 10.3390/ijerph19074163] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 11/16/2022]
Abstract
Eutrophication is an emerging worldwide issue concerning the excessive accumulation of various pollutants in sediments, owing to the release of industrial or household wastewaters to coastal areas. The coastal sediment of Goseong Bay in the Republic of Korea is organically enriched with pollutants, including heavy metals, sulfide, phosphate, and ammonia. Microbial remediation and capping techniques have been suggested as effective routes for sediment remediation. In this study, Bacillus subtilis zeolite (BZ) was used as a sediment capping material, and effective remediation of coastal sediment was observed in a 40-day laboratory microcosm experiment. A significant decrease in the sediment water content and reduced concentration of acid volatile sulfide were observed in the BZ-capped sediment. In the overlying water and pore water, significant decreases in phosphate and dissolved inorganic nitrogen (DIN; NO2-N + NO3-N and NH4-N) concentrations were observed in the BZ-treated experiment. Based on our findings, we conclude that BZ could be an effective capping material for coastal sediment remediation.
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Li D, Hou L, Gao Y, Tian Z, Fan B, Wang F, Li S. Recent Advances in Microbial Synthesis of Poly-γ-Glutamic Acid: A Review. Foods 2022; 11:foods11050739. [PMID: 35267372 PMCID: PMC8909396 DOI: 10.3390/foods11050739] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/12/2022] [Accepted: 02/26/2022] [Indexed: 02/01/2023] Open
Abstract
Poly-γ-glutamic acid (γ-PGA) is a natural, safe, non-immunogenic, biodegradable, and environmentally friendly glutamic biopolymer. γ-PGA has been regarded as a promising bio-based materials in the food field, medical field, even in environmental engineering field, and other industrial fields. Microbial synthesis is an economical and effective way to synthesize γ-PGA. Bacillus species are the most widely studied producing strains. γ-PGA biosynthesis involves metabolic pathway of racemization, polymerization, transfer, and catabolism. Although microbial synthesis of γ-PGA has already been used extensively, productivity and yield remain the major constraints for its industrial application. Metabolic regulation is an attempt to solve the above bottleneck problems and meet the demands of commercialization. Therefore, it is important to understand critical factors that influence γ-PGA microbial synthesis in depth. This review focuses on production strains, biosynthetic pathway, and metabolic regulation. Moreover, it systematically summarizes the functional properties, purification procedure, and industrial application of γ-PGA.
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Affiliation(s)
- Danfeng Li
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China; (D.L.); (L.H.); (Y.G.); (Z.T.); (B.F.)
| | - Lizhen Hou
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China; (D.L.); (L.H.); (Y.G.); (Z.T.); (B.F.)
| | - Yaxin Gao
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China; (D.L.); (L.H.); (Y.G.); (Z.T.); (B.F.)
| | - Zhiliang Tian
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China; (D.L.); (L.H.); (Y.G.); (Z.T.); (B.F.)
| | - Bei Fan
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China; (D.L.); (L.H.); (Y.G.); (Z.T.); (B.F.)
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fengzhong Wang
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Key Laboratory of Agro-Products Processing, Ministry of Agriculture and Rural Affairs, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Correspondence: (F.W.); (S.L.); Tel.: +86-010-62815977 (F.W.); +86-010-62810295 (S.L.)
| | - Shuying Li
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China; (D.L.); (L.H.); (Y.G.); (Z.T.); (B.F.)
- Correspondence: (F.W.); (S.L.); Tel.: +86-010-62815977 (F.W.); +86-010-62810295 (S.L.)
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13
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Jang WJ, Lee GH, Lee JM, Kim TY, Jeon MH, Kim YH, Lee EW. Improving enzyme activity, thermostability and storage stability of β-1,3-1,4-glucanase with poly-γ-glutamic acid produced by Bacillus sp. SJ-10. Enzyme Microb Technol 2020; 143:109703. [PMID: 33375971 DOI: 10.1016/j.enzmictec.2020.109703] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/02/2020] [Accepted: 11/05/2020] [Indexed: 10/23/2022]
Abstract
β-1,3-1,4-glucanase (BG) is an industrially important enzyme owing to its stringent specificity for β-glucan cleavage. In this study, poly-γ-glutamic acid (γ-PGA) was added to BG to investigate its effect on improving the activity and stability of the enzyme. The effect of γ-PGA was investigated by analyzing kinetic and thermodynamic parameters. Compared to control, significant differences (P < .05) in enzyme activity were observed when 1.0 %, 1.5 %, and 2.0 % γ-PGA was added, and the activities were increased 1.23 ± 0.05, 1.23 ± 0.07, and 1.31 ± 0.07-fold, respectively. Regarding thermostability, residual BG activity after a 1 h incubation at 60 °C was 12.53 ± 0.06 % without γ-PGA and 79.02 ± 5.76 % with 1% γ-PGA. The storage stability at 25 °C and 50 °C also increased when γ-PGA was present. The kinetics and thermodynamic investigations indicated that the increased activity and stability of BG when γ-PGA was added were due to increased values of the Vmax, Kcat, and activation energy for denaturation. The findings of this study suggest that adding γ-PGA to BG increases the application value of this enzyme in the food and feed industries.
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Affiliation(s)
- Won Je Jang
- Biopharmaceutical Engineering Major, Division of Applied Bioengineering, Dong-Eui University, Busan, 47340, Republic of Korea; Department of Biotechnology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Ga Hye Lee
- Department of Biotechnology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Jong Min Lee
- Industrial Bio-materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Tae-Yong Kim
- Biopharmaceutical Engineering Major, Division of Applied Bioengineering, Dong-Eui University, Busan, 47340, Republic of Korea
| | - Mi-Hyun Jeon
- Biopharmaceutical Engineering Major, Division of Applied Bioengineering, Dong-Eui University, Busan, 47340, Republic of Korea
| | - Yang-Ho Kim
- Biopharmaceutical Engineering Major, Division of Applied Bioengineering, Dong-Eui University, Busan, 47340, Republic of Korea
| | - Eun-Woo Lee
- Biopharmaceutical Engineering Major, Division of Applied Bioengineering, Dong-Eui University, Busan, 47340, Republic of Korea.
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14
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Sha Y, Qiu Y, Zhu Y, Sun T, Luo Z, Gao J, Feng X, Li S, Xu H. CRISPRi-Based Dynamic Regulation of Hydrolase for the Synthesis of Poly-γ-Glutamic Acid with Variable Molecular Weights. ACS Synth Biol 2020; 9:2450-2459. [PMID: 32794764 DOI: 10.1021/acssynbio.0c00207] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a decomposable polymer and has been useful in various industries. The biological functions of γ-PGA are closely linked with its molecular weight (MW). In this study, we established an efficient method to produce variable MWs of γ-PGA from renewable biomass (Jerusalem artichoke) by Bacillus amyloliquefaciens. First, a systematic engineering strategy was proposed in B. amyloliquefaciens to construct an optimal platform for γ-PGA overproduction, in which 24.95 g/L γ-PGA generation was attained. Second, 27.12 g/L γ-PGA with an MW of 20-30 kDa was obtained by introducing a γ-PGA hydrolase (pgdS) into the platform strain constructed above, which reveals a potential correlation between the expression level of pgdS and MW of γ-PGA. Then, a Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) system was further designed to regulate pgdS expression levels, resulting in γ-PGA with variable MWs. Finally, a combinatorial approach based on three sgRNAs with different repression efficiencies was developed to achieve the dynamic regulation of pgdS and obtain tailor-made γ-PGA production in the MW range of 50-1400 kDa in one strain. This study illustrates a promising approach for the sustainable making of biopolymers with diverse molecular weights in one strain through the controllable expression of hydrolase using the CRISPRi system.
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Affiliation(s)
- Yuanyuan Sha
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Yibin Qiu
- Department of Food Science and Technology, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, P. R. China
| | - Yifan Zhu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Tao Sun
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Zhengshan Luo
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Jian Gao
- School of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, P. R. China
| | - Xiaohai Feng
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Sha Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Hong Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
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15
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Azarhava H, Bajestani MI, Jafari A, Vakilchap F, Mousavi SM. Production and physicochemical characterization of bacterial poly gamma- (glutamic acid) to investigate its performance on enhanced oil recovery. Int J Biol Macromol 2020; 147:1204-1212. [PMID: 31739030 DOI: 10.1016/j.ijbiomac.2019.10.090] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 01/07/2023]
Abstract
Bacillus licheniformis LMG 7559, which is capable of producing extracellular poly gamma- (glutamic acid) (PGA), was provided for the biopolymer synthesis. Using a modified PGA medium for PGA production, the isolated biopolymer, undergone dialysis process mainly for desalination and removal of other impurities. The bacteria produced high molecular weight biopolymers with a weight average molecular weight (M̅n) of 1.6 × 105 g/mole identified by gel permeation chromatography (GPC). Furthermore, GPC analysis was utilized to determine the poly-dispersity of PGA as well as molecular weight variation by cultivation time. The heavy weight fraction of 1.85 × 105 g/mole with poly-dispersity index of 7.42 was distinguished. For the extracted and dialyzed biopolymer, thermal properties were studied using DSC/TGA by which a mass loss of 36 percent was observed. Eventually, the biopolymer solution was injected into the oil saturated heterogeneous porous medium to evaluate the recovery factor enhancement by PGA flooding. It was found that 31.45% of oil in place was recovered by biopolymer flooding, whereas only 16.6% of oil in place was obtained by water flooding.
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Affiliation(s)
- Hadi Azarhava
- Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran
| | - Maryam Ijadi Bajestani
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran
| | - Arezou Jafari
- Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
| | - Farzane Vakilchap
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran
| | - Seyyed Mohammad Mousavi
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
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16
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Li H, Wu S, Du C, Zhong Y, Yang C. Preparation, Performances, and Mechanisms of Microbial Flocculants for Wastewater Treatment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E1360. [PMID: 32093205 PMCID: PMC7068532 DOI: 10.3390/ijerph17041360] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/10/2020] [Accepted: 02/17/2020] [Indexed: 12/15/2022]
Abstract
In recent years, close attention has been paid to microbial flocculants because of their advantages, including safety to humans, environmental friendliness, and acceptable removal performances. In this review, the preparation methods of microbial flocculants were first reviewed. Then, the performances of bioflocculants in the removal of suspended solids, heavy metals, and other organic pollutants from various types of wastewater were described and commented, and the removal mechanisms, including adsorption bridging, charge neutralization, chemical reactions, and charge neutrality, were also discussed. The future research needs on microbial flocculants were also proposed. This review would lead to a better understanding of current status, challenges, and corresponding strategies on microbial flocculants and bioflocculation in wastewater treatment.
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Affiliation(s)
- Huiru Li
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; (H.L.); (S.W.)
| | - Shaohua Wu
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; (H.L.); (S.W.)
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
| | - Cheng Du
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
| | - Yuanyuan Zhong
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
| | - Chunping Yang
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; (H.L.); (S.W.)
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
- Hunan Provincial Environmental Protection Engineering Center for Organic Pollution Control of Urban Water and Wastewater, Changsha 410001, China
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17
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Application of Poly-γ-Glutamic Acid Flocculant to Flocculation–Sedimentation Treatment of Ultrafine Cement Suspension. WATER 2019. [DOI: 10.3390/w11091748] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We examined the effect of poly-γ-glutamic acid flocculant (PGAF) on the removal of ultrafine cement (UFC) particles stabilized by a poly-carboxylate co-polymer, which is a superplasticizer (SP). The flocculation–sedimentation treatment with PGAF successfully removed the SP-stabilized cement particles through the gravitational settling of the formed flocs. The removal efficiency reduced with the increase in the ionic strength, probably because of the shrunk form of poly-γ-glutamic acid (γ-PGA) at high ionic strengths. Increasing the mixing intensity during rapid mixing improved the removal efficiency. A series of flocculation–sedimentation experiments provided a diagram showing the relationship between ionic strengths and the addition amount of PGAF. Our results suggest that PGAF is a good candidate for the purification of cement suspension by flocculation–sedimentation, and a better removal performance can be obtained at lower ionic strengths with intense rapid mixing. From the diagram of the control charts presented in this study, we can determine the optimal addition amount of PGAF for achieving the target removal rate for cement suspension under any ionic strength.
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18
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Deciphering metabolic responses of biosurfactant lichenysin on biosynthesis of poly-γ-glutamic acid. Appl Microbiol Biotechnol 2019; 103:4003-4015. [PMID: 30923871 DOI: 10.1007/s00253-019-09750-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/21/2019] [Accepted: 03/06/2019] [Indexed: 12/19/2022]
Abstract
Poly-γ-glutamic acid (γ-PGA) is an extracellularly produced biodegradable polymer, which has been widely used as agricultural fertilizer, mineral fortifier, cosmetic moisturizer, and drug carrier. This study firstly discovered that lichenysin, as a biosurfactant, showed the capability to enhance γ-PGA production in Bacillus licheniformis. The exogenous addition of lichenysin improved the γ-PGA yield up to 17.9% and 21.9%, respectively, in the native strain B. licheniformis WX-02 and the lichenysin-deficient strain B. licheniformis WX02-ΔlchAC. The capability of intracellular biosynthesis of lichenysin was positively correlated with γ-PGA production. The yield of γ-PGA increased by 25.1% in the lichenysin-enhanced strain B. licheniformis WX02-Psrflch and decreased by 12.2% in the lichenysin-deficient strain WX02-ΔlchAC. Analysis of key enzyme activities and gene expression in the TCA cycle, precursor glutamate synthesis, and γ-PGA synthesis pathway revealed that the existence of lichenysin led to increased γ-PGA via shifting the carbon flux in the TCA cycle towards glutamate and γ-PGA biosynthetic pathways, minimizing by-product formation, and facilitating the uptake of extracellular substrates and the polymerization of glutamate to γ-PGA. Insight into the mechanisms of enhanced production of γ-PGA by lichenysin would define the essential parameters involved in γ-PGA biosynthesis and provide the basis for large-scale production of γ-PGA.
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19
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Advances and prospects of Bacillus subtilis cellular factories: From rational design to industrial applications. Metab Eng 2018; 50:109-121. [DOI: 10.1016/j.ymben.2018.05.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 05/02/2018] [Accepted: 05/10/2018] [Indexed: 01/29/2023]
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20
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Lee JM, Kim JH, Kim KW, Lee BJ, Kim DG, Kim YO, Lee JH, Kong IS. Physicochemical properties, production, and biological functionality of poly-γ-d-glutamic acid with constant molecular weight from halotolerant Bacillus sp. SJ-10. Int J Biol Macromol 2018; 108:598-607. [DOI: 10.1016/j.ijbiomac.2017.12.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/25/2017] [Accepted: 12/08/2017] [Indexed: 12/13/2022]
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21
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Hsueh YH, Huang KY, Kunene SC, Lee TY. Poly-γ-glutamic Acid Synthesis, Gene Regulation, Phylogenetic Relationships, and Role in Fermentation. Int J Mol Sci 2017; 18:E2644. [PMID: 29215550 PMCID: PMC5751247 DOI: 10.3390/ijms18122644] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 02/03/2023] Open
Abstract
Poly-γ-glutamic acid (γ-PGA) is a biodegradable biopolymer produced by several bacteria, including Bacillus subtilis and other Bacillus species; it has good biocompatibility, is non-toxic, and has various potential biological applications in the food, pharmaceutical, cosmetic, and other industries. In this review, we have described the mechanisms of γ-PGA synthesis and gene regulation, its role in fermentation, and the phylogenetic relationships among various pgsBCAE, a biosynthesis gene cluster of γ-PGA, and pgdS, a degradation gene of γ-PGA. We also discuss potential applications of γ-PGA and highlight the established genetic recombinant bacterial strains that produce high levels of γ-PGA, which can be useful for large-scale γ-PGA production.
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Affiliation(s)
- Yi-Huang Hsueh
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan city 32003, Taiwan.
| | - Kai-Yao Huang
- Department of Computer Science and Engineering, Yuan Ze University, Taoyuan city 32003, Taiwan.
- Department of Medical Research, Hsinchu Mackay Memorial Hospital, Hsinchu city 300, Taiwan.
| | - Sikhumbuzo Charles Kunene
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan city 32003, Taiwan.
| | - Tzong-Yi Lee
- Department of Computer Science and Engineering, Yuan Ze University, Taoyuan city 32003, Taiwan.
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22
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Microbial production of poly-γ-glutamic acid. World J Microbiol Biotechnol 2017; 33:173. [DOI: 10.1007/s11274-017-2338-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/30/2017] [Indexed: 10/18/2022]
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23
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Agunbiade MO, Van Heerden E, Pohl CH, Ashafa AT. Flocculating performance of a bioflocculant produced by Arthrobacter humicola in sewage waste water treatment. BMC Biotechnol 2017; 17:51. [PMID: 28606076 PMCID: PMC5469021 DOI: 10.1186/s12896-017-0375-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 06/07/2017] [Indexed: 11/14/2022] Open
Abstract
Background The discharge of poorly treated effluents into the environment has far reaching, consequential impacts on human and aquatic life forms. Thus, we evaluated the flocculating efficiency of our test bioflocculant and we report for the first time the ability of the biopolymeric flocculant produced by Arthrobacter humicola in the treatment of sewage wastewater. This strain was isolated from sediment soil sample at Sterkfontein dam in the Eastern Free State province of South Africa. Results Basic Local Alignment Search Tool (BLAST) analysis of the nucleotide sequence of the 16S rDNA revealed the bacteria to have 99% similarity to Arthrobacter humicola strain R1 and the sequence was deposited in the Gene bank as Arthrobacter humicola with accession number KC816574.1. Flocculating activity was enhanced with the aid of divalent cations, pH 12, at a dosage concentration of 0.8 mg/mL. The purified bioflocculant was heat stable and could retain more than 78% of its flocculating activity after heating at 100 °C for 25 min. Fourier Transform Infrared Spectroscopy analysis demonstrated the presence of hydroxyl and carboxyl moieties as the functional groups. The thermogravimetric analysis was used to monitor the pyrolysis profile of the purified bioflocculant and elemental composition revealed C: O: Na: P: K with 13.90: 41.96: 26.79: 16.61: 0.74 weight percentage respectively. The purified bioflocculant was able to remove chemical oxygen demand, biological oxygen demand, suspended solids, nitrate and turbidity from sewage waste water at efficiencies of 65.7%, 63.5%, 55.7%, 71.4% and 81.3% respectively. Conclusions The results of this study indicate the possibility of using the bioflocculant produced by Arthrobacter humicola as a potential alternative to synthesized chemical flocculants in sewage waste water treatment and other industrial waste water.
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Affiliation(s)
- Mayowa Oladele Agunbiade
- Phytomedicine and Phytopharmacology Research Group, Department of Plant Sciences, University of the Free State, Qwaqwa Campus, P. Bag X13, Phuthaditjabha, 9866, South Africa. .,Department of Microbial, Biochemical & Food Biotechnology, University of the Free State, P.O. Box 339, Nelson Mandela Drive, Bloemfontein, 9301, South Africa.
| | - Esta Van Heerden
- Department of Microbial, Biochemical & Food Biotechnology, University of the Free State, P.O. Box 339, Nelson Mandela Drive, Bloemfontein, 9301, South Africa
| | - Carolina H Pohl
- Department of Microbial, Biochemical & Food Biotechnology, University of the Free State, P.O. Box 339, Nelson Mandela Drive, Bloemfontein, 9301, South Africa
| | - Anofi Tom Ashafa
- Phytomedicine and Phytopharmacology Research Group, Department of Plant Sciences, University of the Free State, Qwaqwa Campus, P. Bag X13, Phuthaditjabha, 9866, South Africa
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24
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Li Z, He G, Hua J, Wu M, Guo W, Gong J, Zhang J, Qiao C. Preparation of γ-PGA hydrogels and swelling behaviors in salt solutions with different ionic valence numbers. RSC Adv 2017. [DOI: 10.1039/c6ra26419k] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this paper, a novel poly γ-glutamic acid (γ-PGA) hydrogel was successfully synthesized by solution polymerization and ethylene glycol diglycidyl ether (EGDE) was used as crosslinker.
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Affiliation(s)
- Zheng Li
- Key Laboratory of Advanced Textile Composites (Tianjin Polytechnic University)
- Ministry of Education
- Tianjin 300387
- China
- School of Textiles
| | - Guidong He
- Key Laboratory of Advanced Textile Composites (Tianjin Polytechnic University)
- Ministry of Education
- Tianjin 300387
- China
- School of Textiles
| | - Jiachuan Hua
- Key Laboratory of Advanced Textile Composites (Tianjin Polytechnic University)
- Ministry of Education
- Tianjin 300387
- China
- School of Textiles
| | - Maoqi Wu
- Key Laboratory of Advanced Textile Composites (Tianjin Polytechnic University)
- Ministry of Education
- Tianjin 300387
- China
- School of Textiles
| | - Wen Guo
- Key Laboratory of Advanced Textile Composites (Tianjin Polytechnic University)
- Ministry of Education
- Tianjin 300387
- China
- School of Textiles
| | - Jixian Gong
- Key Laboratory of Advanced Textile Composites (Tianjin Polytechnic University)
- Ministry of Education
- Tianjin 300387
- China
- School of Textiles
| | - Jianfei Zhang
- Key Laboratory of Advanced Textile Composites (Tianjin Polytechnic University)
- Ministry of Education
- Tianjin 300387
- China
- School of Textiles
| | - Changsheng Qiao
- Key Laboratory of Industrial Microbiology
- Ministry of Education
- Tianjin University of Science and Technology
- Tianjin 300457
- China
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25
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Hu P, Zhang Z, Shen F, Yu X, Li M, Ni H, Li L. Poly-γ-glutamic acid coupled Pseudomonas putida cells surface-displaying metallothioneins: composited copper(ii) biosorption and inducible flocculation in aqueous solution. RSC Adv 2017. [DOI: 10.1039/c7ra01546a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Schematic illustration of the preparation, biosorption, and induced flocculation of the biocomposite MB546-PGA.
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Affiliation(s)
- Penggao Hu
- State Key Laboratory of Agricultural Microbiology
- College of Life Science and Technology
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Zhongna Zhang
- State Key Laboratory of Agricultural Microbiology
- College of Life Science and Technology
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Fei Shen
- State Key Laboratory of Agricultural Microbiology
- College of Life Science and Technology
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Xun Yu
- State Key Laboratory of Agricultural Microbiology
- College of Life Science and Technology
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Mingshun Li
- State Key Laboratory of Agricultural Microbiology
- College of Life Science and Technology
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Hong Ni
- College of Life Sciences
- Hubei University
- Wuhan 430062
- China
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology
- College of Life Science and Technology
- Huazhong Agricultural University
- Wuhan 430070
- China
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26
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Peng Y, Zhang T, Mu W, Miao M, Jiang B. Intracellular synthesis of glutamic acid in Bacillus methylotrophicus SK19.001, a glutamate-independent poly(γ-glutamic acid)-producing strain. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2016; 96:66-72. [PMID: 26112100 DOI: 10.1002/jsfa.7318] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 06/21/2015] [Accepted: 06/22/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND Bacillus methylotrophicus SK19.001 is a glutamate-independent strain that produces poly(γ-glutamic acid) (γ-PGA), a polymer of D- and L-glutamic acids that possesses applications in food, the environment, agriculture, etc. This study was undertaken to explore the synthetic pathway of intracellular L- and D-glutamic acid in SK19.001 by investigating the effects of tricarboxylic acid cycle intermediates and different amino acids as metabolic precursors on the production of γ-PGA and analyzing the activities of the enzymes involved in the synthesis of L- and D-glutamate. RESULTS Tricarboxylic acid cycle intermediates and amino acids could participate in the synthesis of γ-PGA via independent pathways in SK19.001. L-Aspartate aminotransferase, L-glutaminase and L-glutamate synthase were the enzymatic sources of L-glutamate. Glutamate racemase was responsible for the formation of D-glutamate for the synthesis of γ-PGA, and the synthetase had stereoselectivity for glutamate substrate. CONCLUSION The enzymatic sources of L-glutamate were investigated for the first time in the glutamate-independent γ-PGA-producing strain, and multiple enzymatic sources of L-glutamate were verified in SK19.001, which will benefit efforts to improve production of γ-PGA with metabolic engineering strategies.
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Affiliation(s)
- Yingyun Peng
- State Key Laboratory of Food Science and Technology, Ministry of Education, Key Laboratory of Carbohydrate Chemistry & Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
- School of Chemical and Biological Engineering, Yancheng Institute of Technology, Yancheng, Jiangsu 22400, China
| | - Tao Zhang
- State Key Laboratory of Food Science and Technology, Ministry of Education, Key Laboratory of Carbohydrate Chemistry & Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Ministry of Education, Key Laboratory of Carbohydrate Chemistry & Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Ming Miao
- State Key Laboratory of Food Science and Technology, Ministry of Education, Key Laboratory of Carbohydrate Chemistry & Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Bo Jiang
- State Key Laboratory of Food Science and Technology, Ministry of Education, Key Laboratory of Carbohydrate Chemistry & Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
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Luo Z, Guo Y, Liu J, Qiu H, Zhao M, Zou W, Li S. Microbial synthesis of poly-γ-glutamic acid: current progress, challenges, and future perspectives. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:134. [PMID: 27366207 PMCID: PMC4928254 DOI: 10.1186/s13068-016-0537-7] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/31/2016] [Indexed: 05/22/2023]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a naturally occurring biopolymer made from repeating units of l-glutamic acid, d-glutamic acid, or both. Since some bacteria are capable of vigorous γ-PGA biosynthesis from renewable biomass, γ-PGA is considered a promising bio-based chemical and is already widely used in the food, medical, and wastewater industries due to its biodegradable, non-toxic, and non-immunogenic properties. In this review, we consider the properties, biosynthetic pathway, production strategies, and applications of γ-PGA. Microbial biosynthesis of γ-PGA and the molecular mechanisms regulating production are covered in particular detail. Genetic engineering and optimization of the growth medium, process control, and downstream processing have proved to be effective strategies for lowering the cost of production, as well as manipulating the molecular mass and conformational/enantiomeric properties that facilitate screening of competitive γ-PGA producers. Finally, future prospects of microbial γ-PGA production are discussed in light of recent progress, challenges, and trends in this field.
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Affiliation(s)
- Zhiting Luo
- />College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China
| | - Yuan Guo
- />National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, 530004 China
| | - Jidong Liu
- />College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China
| | - Hua Qiu
- />College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China
| | - Mouming Zhao
- />College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China
| | - Wei Zou
- />College of Bioengineering, Sichuan University of Science and Engineering, Zigong, 643000 Sichuan China
| | - Shubo Li
- />College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004 China
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Yan S, Yao H, Chen Z, Zeng S, Xi X, Wang Y, He N, Li Q. Poly-γ-glutamic acid produced from Bacillus licheniformis CGMCC 2876 as a potential substitute for polyacrylamide in the sugarcane industry. Biotechnol Prog 2015; 31:1287-94. [PMID: 26033934 DOI: 10.1002/btpr.2118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 05/21/2015] [Indexed: 11/06/2022]
Abstract
As an environmentally friendly and industrially useful biopolymer, poly-γ-glutamic acid (γ-PGA) from Bacillus licheniformis CGMCC 2876 was characterized by the high-resolution mass spectrometry and (1)H NMR. A flocculating activity of 11,474.47 U mL(-1) obtained with γ-PGA, and the effects of carbon sources, ions, and chemical properties (D-/L-composition and molecular weight) on the production and flocculating activity of γ-PGA were discussed. Being a bioflocculant in the sugar refinery process, the color and turbidity of the sugarcane juice was IU 1,877.36 and IU 341.41 with 0.8 ppm of γ-PGA, respectively, which was as good as the most widely used chemically synthesized flocculant in the sugarcane industry--polyacrylamide with 1 ppm. The γ-PGA produced from B. licheniformis CGMCC 2876 could be a promising alternate of chemically synthesized flocculants in the sugarcane industry.
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Affiliation(s)
- Shan Yan
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China.,Dept. of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902,, Unites States
| | - Haosheng Yao
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China
| | - Zhen Chen
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China
| | - Shengquan Zeng
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China
| | - Xi Xi
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China
| | - Yuanpeng Wang
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China
| | - Ning He
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China
| | - Qingbiao Li
- Dept. of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005,, P.R. China.,Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, 361005,, P.R. China
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Ogunleye A, Bhat A, Irorere VU, Hill D, Williams C, Radecka I. Poly-γ-glutamic acid: production, properties and applications. MICROBIOLOGY-SGM 2014; 161:1-17. [PMID: 25288645 DOI: 10.1099/mic.0.081448-0] [Citation(s) in RCA: 208] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a naturally occurring biopolymer made up of repeating units of l-glutamic acid, d-glutamic acid or both. γ-PGA can exhibit different properties (conformational states, enantiomeric properties and molecular mass). Owing to its biodegradable, non-toxic and non-immunogenic properties, it has been used successfully in the food, medical and wastewater industries. Amongst other novel applications, it has the potential to be used for protein crystallization, as a soft tissue adhesive and a non-viral vector for safe gene delivery. This review focuses on the production, properties and applications of γ-PGA. Each application of γ-PGA utilizes specific properties attributed to various forms of γ-PGA. As a result of its growing applications, more strains of bacteria need to be investigated for γ-PGA production to obtain high yields of γ-PGA with different properties. Many medical applications (especially drug delivery) have exploited α-PGA. As γ-PGA is essentially different from α-PGA (i.e. it does not involve a chemical modification step and is not susceptible to proteases), it could be better utilized for such medical applications. Optimization of γ-PGA with respect to cost of production, molecular mass and conformational/enantiomeric properties is a major step in making its application practical. Analyses of γ-PGA production and knowledge of the enzymes and genes involved in γ-PGA production will not only help increase productivity whilst reducing the cost of production, but also help to understand the mechanism by which γ-PGA is effective in numerous applications.
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Affiliation(s)
- Adetoro Ogunleye
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - Aditya Bhat
- Aber Instruments, Science Park, Aberystwyth SY23 3AH, UK
| | - Victor U Irorere
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - David Hill
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - Craig Williams
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - Iza Radecka
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
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Lee NR, Go TH, Lee SM, Jeong SY, Park GT, Hong CO, Son HJ. In vitro evaluation of new functional properties of poly-γ-glutamic acid produced by Bacillus subtilis D7. Saudi J Biol Sci 2014; 21:153-8. [PMID: 24600308 PMCID: PMC3942858 DOI: 10.1016/j.sjbs.2013.09.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/10/2013] [Accepted: 09/10/2013] [Indexed: 11/24/2022] Open
Abstract
We investigated the functionality of poly-γ-glutamic acid (γ-PGA), which is produced by Bacillus subtilis D7, for its potential applications in medicine and cosmetics. The γ-PGA had angiotensin-converting enzyme (ACE) inhibition activity. ACE inhibition activity was dependent on the γ-PGA concentration; the highest ACE inhibition activity was observed at 1.25 mg/l of γ-PGA. IC50 (0.108 mg/ml) of the γ-PGA was lower than that of standard ACE inhibitory drug, N-[(S)-mercapto-2-methylpropionyl]-L-proline (0.247 mg/ml). The γ-PGA also had water-holding capacity and hygroscopicity. Furthermore, the γ-PGA inhibited growth of some pathogenic bacteria, including Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, Klebsiella pneumonia and Esherichia coli. The γ-PGA exhibited a good metal adsorption capacity; Cr (VI) adsorption capacity of γ-PGA increased with decreasing pH, and the maximal adsorption was observed at pH 2. Our results suggest that γ-PGA may be expected to be widely applied in cosmetics, biomedical and environmental industries with the feature of being less harmful to humans and the environment.
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Affiliation(s)
- Na-Ri Lee
- Department of Life Science and Environmental Biochemistry, Life and Industry Convergence Institute, Pusan National University, Miryang 627-706, Republic of Korea
| | - Tae-Hun Go
- Department of Life Science and Environmental Biochemistry, Life and Industry Convergence Institute, Pusan National University, Miryang 627-706, Republic of Korea
| | - Sang-Mee Lee
- Department of Life Science and Environmental Biochemistry, Life and Industry Convergence Institute, Pusan National University, Miryang 627-706, Republic of Korea
| | - Seong-Yun Jeong
- Department of Medical Life Science, Catholic University of Daegu, Daegu 712-784, Republic of Korea
| | - Geun-Tae Park
- Research and University-Industry Cooperation, Pusan National University, Busan 609-735, Republic of Korea
| | - Chang-Oh Hong
- Department of Life Science and Environmental Biochemistry, Life and Industry Convergence Institute, Pusan National University, Miryang 627-706, Republic of Korea
| | - Hong-Joo Son
- Department of Life Science and Environmental Biochemistry, Life and Industry Convergence Institute, Pusan National University, Miryang 627-706, Republic of Korea
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CHANG J, ZHONG Z, XU H, YAO Z, CHEN R. Fabrication of Poly(γ-glutamic acid)-coated Fe3O4 Magnetic Nanoparticles and Their Application in Heavy Metal Removal. Chin J Chem Eng 2013. [DOI: 10.1016/s1004-9541(13)60629-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Cosa S, Ugbenyen AM, Mabinya LV, Rumbold K, Okoh AI. Characterization and flocculation efficiency of a bioflocculant produced by a marine Halobacillus. ENVIRONMENTAL TECHNOLOGY 2013; 34:2671-2679. [PMID: 24527629 DOI: 10.1080/09593330.2013.786104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We reported earlier on the bioflocculant production potential of Halobacillus sp. Mvuyo, a marine bacteria isolated from Algoa Bay sediment samples. In this paper we report on the detailed characterization of the purified bioflocculant composed of polysaccharide and protein. The optimum dose of the purified bioflocculant for the clarification of 4 g l(-1) kaolin clay suspension was 0.2 mg ml(-1) at neutral pH. Scanning electron micrograph (SEM) revealed the bioflocculant to have an amorphous structure. The Fourier transform infrared (FTIR) spectrum exhibited the presence of hydroxyl, carboxyl and amino groups in its structure. The bioflocculant was thermostable with relative bioflocculant activity residue of 74.4% after heat treatment at 100 degrees C. Moreover thermogravimetric analysis (TGA) exhibited a degradation temperature (Td) of - 140 degrees C. The flocculation efficiency of the bioflocculant was 86.2% compared with 82.6%, 74.5% and 70.9% for polyethylimine, ferric chloride and alum, respectively. This bioflocculant has immense promise as a substitute to inorganic and synthetic flocculants in view of their hazard implications.
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Affiliation(s)
- Sekelwa Cosa
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
| | - Anthony M Ugbenyen
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
| | - Leonard V Mabinya
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
| | - Karl Rumbold
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Anthony I Okoh
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
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Zhao C, Zhang Y, Wei X, Hu Z, Zhu F, Xu L, Luo M, Liu H. Production of ultra-high molecular weight poly-γ-glutamic acid with Bacillus licheniformis P-104 and characterization of its flocculation properties. Appl Biochem Biotechnol 2013; 170:562-72. [PMID: 23553109 DOI: 10.1007/s12010-013-0214-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 03/21/2013] [Indexed: 10/27/2022]
Abstract
A novel strain of Bacillus licheniformis P-104 was isolated from Chinese soybean paste to produce a bioflocculant. The bioflocculant was confirmed as ultra-high molecular weight poly-γ-glutamic acid (γ-PGA) using Fourier transform infrared spectrum, high-performance liquid chromatography, and gel permeation chromatography with multi-angle laser light scattering. The production technology and flocculation properties of γ-PGA were investigated. By fed-batch fermentation in a 7-L bioreactor, the maximum γ-PGA yield reached 41.6 g L(-1) with a productivity rate of 1.07 g L(-1) h(-1). The flocculating activity of γ-PGA for kaolin suspension was 33.5±1.6 1/OD under the optimized flocculation conditions (6 mM Ca(2+), 1.5 mg L(-1) γ-PGA, and pH 6.0). The optimized dosage of γ-PGA for flocculation was just about 30 % of that of reported γ-PGA produced by other strains. Moreover, the flocculation activity of γ-PGA produced by strain P-104 was much higher than commercial γ-PGA with the molecular weight ranging 200-500 kDa and 1,500-2,500 kDa. This study provided a promising strain and an efficient method for production of ultra-high molecular weight γ-PGA which could be used as a potential green bioflocculant.
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Affiliation(s)
- Caifeng Zhao
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
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Zheng H, Gao Z, Yin J, Tang X, Ji X, Huang H. Harvesting of microalgae by flocculation with poly (γ-glutamic acid). BIORESOURCE TECHNOLOGY 2012; 112:212-20. [PMID: 22425514 DOI: 10.1016/j.biortech.2012.02.086] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/07/2012] [Accepted: 02/13/2012] [Indexed: 05/06/2023]
Abstract
In an effort to search for an efficient and environmentally friendly harvesting method, a commercially available microbial flocculant poly (γ-glutamic acid) (γ-PGA) was used to harvest oleaginous microalgae. Conditions for flocculation of marine Chlorella vulgaris and freshwater Chlorella protothecoides were optimized by response surface methodology (RSM) and determined to be 22.03 mg L(-1) γ-PGA, 0.57 g L(-1) biomass, and 11.56 g L(-1) salinity, and 19.82 mg L(-1) γ-PGA and 0.60 g L(-1) biomass, respectively. Application of the two optimized flocculation methods to Nannochloropsis oculata LICME 002, Phaeodactylum tricornutum, C. vulgaris LICME 001, and Botryococcus braunii LICME 003 gave no less than 90% flocculation efficiency and a concentration factor greater than 20. Micrographs of the harvested microalgal cells showed no damage to cell integrity, and hence no lipid loss during the process. The results show that flocculation with γ-PGA is feasible for harvesting microalgae for biodiesel production.
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Affiliation(s)
- Hongli Zheng
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, No. 5, Xinmofan Road, Nanjing 210009, People's Republic of China
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Bajaj I, Singhal R. Poly (glutamic acid)--an emerging biopolymer of commercial interest. BIORESOURCE TECHNOLOGY 2011; 102:5551-61. [PMID: 21377358 DOI: 10.1016/j.biortech.2011.02.047] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 02/09/2011] [Accepted: 02/10/2011] [Indexed: 05/08/2023]
Abstract
Poly (γ-glutamic acid) (PGA) is water-soluble, anionic, biodegradable, and edible biopolymer produced by Bacillus subtilis. It has multifarious potential applications in foods, pharmaceuticals, healthcare, water treatment and other fields. The production of PGA has already been established on the industrial scale. Various studies regarding the fermentative production, downstream processing and characterization of PGA have been reported in the literature. This review provides updated information on fermentative production of PGA by various bacterial strains and effect of fermentation conditions and media component on production of PGA in submerged as well as solid state fermentation. Information on the application of genetic engineering for enhancement of yield of PGA, kinetic studies for production of PGA in submerged fermentation and recovery and purification of PGA is included. An attempt has also been made to review the current and potential applications of PGA. This review may contribute to further development of this commercially and academically interesting biopolymer.
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Affiliation(s)
- Ishwar Bajaj
- Food Engineering and Technology Department, Institute of Chemical Technology, Matunga, Mumbai 400 019, India
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