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Saejung C, Phonaiam S, Kotthale P, Chaiyarat A. Bacterial cellulose as a reinforcement material of alginate beads improves effectiveness and recycling potential of immobilized photosynthetic bacteria for cooking oil waste removal. Carbohydr Polym 2024; 324:121532. [PMID: 37985061 DOI: 10.1016/j.carbpol.2023.121532] [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: 09/13/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/22/2023]
Abstract
The rapid degradation of alginate beads limits the lifespan of immobilized cells. In this study, bacterial cellulose (BC) incorporated in alginate was used to improve the mechanical properties, swelling ratio, and recycling time of the immobilized photosynthetic bacterium Rhodopseudomonas faecalis PA2 for the removal of cooking oil residues. Beads reinforced with 25 and 50% BC showed a higher Young's modulus and compressive strength and a lower swelling ratio than the control treatment (0% BC). The incorporation of 50% BC increased biomass production and oil removal. Field-emission scanning electron microscopy revealed several bacteria-infested internal pores in the reinforced beads, indicating bacterial growth in the presence of BC. Bacterial viability was verified by BC immersion in the bacterial culture broth and by injecting bacteria into the BC matrix. Without BC reinforcement, beads collapsed after reuse in two batches, whereas reinforced beads could be reused for five batches, resulting in an oil removal rate of up to 76.3 %. Our results show that BC can be used as an alginate reinforcing material to improve bead stability and prolong the effective recycling period of immobilized bacteria without negatively affecting bacterial growth or waste oil removal.
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Affiliation(s)
- Chewapat Saejung
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
| | - Saitharn Phonaiam
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Prawphan Kotthale
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Anuwat Chaiyarat
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
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2
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Yang Y, Zhou B, Yu L, Song G, Ge J, Du R. Biosynthesis and characterization of antibacterial bacterial cellulose composite membrane composed of montmorillonite and exopolysaccharides. Int J Biol Macromol 2023; 253:127477. [PMID: 37863143 DOI: 10.1016/j.ijbiomac.2023.127477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 10/22/2023]
Abstract
Bacterial cellulose (BC), as a natural renewable polymer material, has the advantages of porous nanonetwork structure, high degree of polymerization, high purity, high crystallinity, excellent mechanical properties and biocompatibility. However, BC lacks antibacterial properties, which leads to the limitation of BC material in food packaging and medical materials. In this study, a new antibacterial material using the combination of montmorillonite (MMT), BC and exopolysaccharides (EPS) produced by Weissella confusa H2 was synthesized. Fourier infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis showed that BC-EPS, BC-MMT and BC-EPS-MMT composite membranes conformed to the typical type I cellulose structure. Compared to BC membrane, scanning electron microscopy (SEM) showed that the porosity of BC-EPS, BC-MMT and BC-EPS-MMT composite membranes was low and compact. The physical properties of BC-EPS, BC-MTT and BC-EPS-MTT composite membranes showed lower water vapor transmittance. The BC-MTT and BC-EPS-MTT composite membranes exhibit a lower swelling ratio in 120 min. The thermal properties show that BC-EPS, BC-MTT and BC-EPS-MTT composite membranes have higher thermal stability (352 °C, 310 °C, 314 °C). Additionally, both BC-MMT and BC-EPS-MMT demonstrated strong inhibitory effects against various bacterial strains, including Staphylococcus aureus, Escherichia coli, Salmonella paratyphi A, and Bacillus subtilis. The exceptional properties exhibited by composite membranes establishes them as a highly promising option in the field of food packaging and medical material applications.
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Affiliation(s)
- Yi Yang
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Bosen Zhou
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Liansheng Yu
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Gang Song
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, China; Hebei University of Environmental Engineering, Hebei Key Laboratory of Agroecological Safety, Qinhuangdao 066102, China.
| | - Jingping Ge
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, China; Hebei University of Environmental Engineering, Hebei Key Laboratory of Agroecological Safety, Qinhuangdao 066102, China.
| | - Renpeng Du
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, China; Hebei University of Environmental Engineering, Hebei Key Laboratory of Agroecological Safety, Qinhuangdao 066102, China.
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3
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Tatarusanu SM, Lupascu FG, Profire BS, Szilagyi A, Gardikiotis I, Iacob AT, Caluian I, Herciu L, Giscă TC, Baican MC, Crivoi F, Profire L. Modern Approaches in Wounds Management. Polymers (Basel) 2023; 15:3648. [PMID: 37688274 PMCID: PMC10489962 DOI: 10.3390/polym15173648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 08/27/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
Wound management represents a well-known continuous challenge and concern of the global healthcare systems worldwide. The challenge is on the one hand related to the accurate diagnosis, and on the other hand to establishing an effective treatment plan and choosing appropriate wound care products in order to maximize the healing outcome and minimize the financial cost. The market of wound dressings is a dynamic field which grows and evolves continuously as a result of extensive research on developing versatile formulations with innovative properties. Hydrogels are one of the most attractive wound care products which, in many aspects, are considered ideal for wound treatment and are widely exploited for extension of their advantages in healing process. Smart hydrogels (SHs) offer the opportunities of the modulation physico-chemical properties of hydrogels in response to external stimuli (light, pressure, pH variations, magnetic/electric field, etc.) in order to achieve innovative behavior of their three-dimensional matrix (gel-sol transitions, self-healing and self-adapting abilities, controlled release of drugs). The SHs response to different triggers depends on their composition, cross-linking method, and manufacturing process approach. Both native or functionalized natural and synthetic polymers may be used to develop stimuli-responsive matrices, while the mandatory characteristics of hydrogels (biocompatibility, water permeability, bioadhesion) are preserved. In this review, we briefly present the physiopathology and healing mechanisms of chronic wounds, as well as current therapeutic approaches. The rational of using traditional hydrogels and SHs in wound healing, as well as the current research directions for developing SHs with innovative features, are addressed and discussed along with their limitations and perspectives in industrial-scale manufacturing.
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Affiliation(s)
- Simona-Maria Tatarusanu
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 Universitatii Street, 700115 Iasi, Romania; (S.-M.T.); (F.-G.L.); (A.-T.I.); (I.C.); (L.H.)
- Research & Development Department, Antibiotice Company, 1 Valea Lupului Street, 707410 Iasi, Romania
| | - Florentina-Geanina Lupascu
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 Universitatii Street, 700115 Iasi, Romania; (S.-M.T.); (F.-G.L.); (A.-T.I.); (I.C.); (L.H.)
| | - Bianca-Stefania Profire
- Department of Internal Medicine, Faculty of Medicine, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 University Street, 700115 Iasi, Romania;
| | - Andrei Szilagyi
- Advanced Research and Development Center for Experimental Medicine (CEMEX), University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 University Street, 700115 Iasi, Romania; (A.S.); (I.G.)
| | - Ioannis Gardikiotis
- Advanced Research and Development Center for Experimental Medicine (CEMEX), University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 University Street, 700115 Iasi, Romania; (A.S.); (I.G.)
| | - Andreea-Teodora Iacob
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 Universitatii Street, 700115 Iasi, Romania; (S.-M.T.); (F.-G.L.); (A.-T.I.); (I.C.); (L.H.)
| | - Iulian Caluian
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 Universitatii Street, 700115 Iasi, Romania; (S.-M.T.); (F.-G.L.); (A.-T.I.); (I.C.); (L.H.)
| | - Lorena Herciu
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 Universitatii Street, 700115 Iasi, Romania; (S.-M.T.); (F.-G.L.); (A.-T.I.); (I.C.); (L.H.)
| | - Tudor-Catalin Giscă
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 University Street 700115 Iasi, Romania;
| | - Mihaela-Cristina Baican
- Department of Pharmaceutical Physics, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 University Street, 700115 Iasi, Romania;
| | - Florina Crivoi
- Department of Pharmaceutical Physics, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 University Street, 700115 Iasi, Romania;
| | - Lenuta Profire
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy “Grigore T. Popa” of Iasi, 16 Universitatii Street, 700115 Iasi, Romania; (S.-M.T.); (F.-G.L.); (A.-T.I.); (I.C.); (L.H.)
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Shahzad A, Ullah MW, Ali J, Aziz K, Javed MA, Shi Z, Manan S, Ul-Islam M, Nazar M, Yang G. The versatility of nanocellulose, modification strategies, and its current progress in wastewater treatment and environmental remediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:159937. [PMID: 36343829 DOI: 10.1016/j.scitotenv.2022.159937] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/27/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Deterioration in the environmental ecosystems through the depletion of nonrenewable resources and the burden of deleterious contaminants is considered a global concern. To this end, great interest has been shown in the use of renewable and environmentally-friendly reactive materials dually to promote environmental sustainability and cope with harmful contaminants. Among the different available options, the use of nanocellulose (NC) as an environmentally benign and renewable natural nanomaterial is an attractive candidate for environmental remediation owing to its miraculous physicochemical characteristics. This review discusses the intrinsic properties and the structural aspects of different types of NC, including cellulose nanofibrils (CNFs), cellulose nanocrystals (CNCs), and bacterial cellulose (BC) or bacterial nanocellulose (BNC). Also, the different modification strategies involving the functionalization or hybridization of NC by using different functional and reactive materials aimed at wastewater remediation have been elaborated. The modified or hybridized NC has been explored for its applications in the removal or degradation of aquatic contaminants through adsorption, filtration, coagulation, catalysis, photocatalysis, and pollutant sensing. This review highlights the role of NC in the modified composites and describes the underlying mechanisms involved in the removal of contaminants. The life-cycle assessment (LCA) of NC is discussed to unveil the hidden risks associated with its production to the final disposal. Moreover, the contribution of NC in the promotion of waste management at different stages has been described in the form of the five-Rs strategy. In summary, this review provides rational insights to develop NC-based environmentally-friendly reactive materials for the removal and degradation of hazardous aquatic contaminants.
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Affiliation(s)
- Ajmal Shahzad
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Muhammad Wajid Ullah
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China; Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, PR China.
| | - Jawad Ali
- School of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065, PR China
| | - Kazim Aziz
- College of Earth and Environmental Sciences, University of the Punjab, Lahore, Pakistan
| | - Muhammad Asif Javed
- College of Earth and Environmental Sciences, University of the Punjab, Lahore, Pakistan
| | - Zhijun Shi
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Sehrish Manan
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Mazhar Ul-Islam
- Department of Chemical Engineering, College of Engineering, Dhofar University, Salalah 211, Oman
| | - Mudasir Nazar
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Guang Yang
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China.
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5
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Schultz J, Modolon F, Rosado AS, Voolstra CR, Sweet M, Peixoto RS. Methods and Strategies to Uncover Coral-Associated Microbial Dark Matter. mSystems 2022; 7:e0036722. [PMID: 35862824 PMCID: PMC9426423 DOI: 10.1128/msystems.00367-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The vast majority of environmental microbes have not yet been cultured, and most of the knowledge on coral-associated microbes (CAMs) has been generated from amplicon sequencing and metagenomes. However, exploring cultured CAMs is key for a detailed and comprehensive characterization of the roles of these microbes in shaping coral health and, ultimately, for their biotechnological use as, for example, coral probiotics and other natural products. Here, the strategies and technologies that have been used to access cultured CAMs are presented, while advantages and disadvantages associated with each of these strategies are discussed. We highlight the existing gaps and potential improvements in culture-dependent methodologies, indicating several possible alternatives (including culturomics and in situ diffusion devices) that could be applied to retrieve the CAM "dark matter" (i.e., the currently undescribed CAMs). This study provides the most comprehensive synthesis of the methodologies used to recover the cultured coral microbiome to date and draws suggestions for the development of the next generation of CAM culturomics.
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Affiliation(s)
- Júnia Schultz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Flúvio Modolon
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexandre S. Rosado
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Michael Sweet
- Aquatic Research Facility, Environmental Sustainability Research Centre, University of Derby, Derby, UK
| | - Raquel S. Peixoto
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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6
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Zvinavashe AT, Laurent J, Mhada M, Sun H, Fouda HME, Kim D, Mouhib S, Kouisni L, Marelli B. Programmable design of seed coating function induces water-stress tolerance in semi-arid regions. NATURE FOOD 2021; 2:485-493. [PMID: 37117674 DOI: 10.1038/s43016-021-00315-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 06/03/2021] [Indexed: 04/30/2023]
Abstract
In semi-arid regions, water stress during seed germination and early seedling growth is the highest cause of crop loss. In nature, some seeds (for example, chia and basil) produce a mucilage-based hydrogel that creates a germination-promoting microenvironment by retaining water, regulating nutrient entry and facilitating interactions with beneficial microorganisms. Inspired by this strategy, a two-layered biopolymer-based seed coating has been developed to increase germination and water-stress tolerance in semi-arid, sandy soils. Seeds are coated with a silk/trehalose inner layer containing rhizobacteria and a pectin/carboxymethylcellulose outer layer that reswells upon sowing and acts as a water jacket. Using Phaseolus vulgaris (common bean) cultured under water-stress conditions in an experimental farm in Ben Guerir, Morocco, the proposed seed coating effectively delivered rhizobacteria to form root nodules, resulted in plants with better health and mitigated water stress in drought-prone marginal lands. A programmable seed coating technology has the potential to increase seed germination and water-stress tolerance in semi-arid, sandy soils.
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Affiliation(s)
- Augustine T Zvinavashe
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Julie Laurent
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Manal Mhada
- AgroBiosciences Department (AgBS), Mohammed VI Polytechnic University (UM6P), Ben-Guerir, Morocco
| | - Hui Sun
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Henri Manu Effa Fouda
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Doyoon Kim
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Salma Mouhib
- AgroBiosciences Department (AgBS), Mohammed VI Polytechnic University (UM6P), Ben-Guerir, Morocco
| | - Lamfeddal Kouisni
- AgroBiosciences Department (AgBS), Mohammed VI Polytechnic University (UM6P), Ben-Guerir, Morocco
- African Sustainable Agriculture Research Institute, Mohammed VI Polytechnic University (ASARI-UM6P), Laayoune, Morocco
| | - Benedetto Marelli
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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7
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Orekan J, Barbé B, Oeng S, Ronat JB, Letchford J, Jacobs J, Affolabi D, Hardy L. Culture media for clinical bacteriology in low- and middle-income countries: challenges, best practices for preparation and recommendations for improved access. Clin Microbiol Infect 2021; 27:1400-1408. [PMID: 34015533 DOI: 10.1016/j.cmi.2021.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/20/2021] [Accepted: 05/04/2021] [Indexed: 01/20/2023]
Abstract
BACKGROUND Culture media are fundamental in clinical microbiology. In laboratories in low- and middle-income countries (LMICs), they are mostly prepared in-house, which is challenging. OBJECTIVES This narrative review describes challenges related to culture media in LMICs, compiles best practices for in-house media preparation, gives recommendations to improve access to quality-assured culture media products in LMICs and formulates outstanding questions for further research. SOURCES Scientific literature was searched using PubMed and predefined MeSH terms. In addition, grey literature was screened, including manufacturer's websites and manuals as well as microbiology textbooks. CONTENT Bacteriology laboratories in LMICs often face challenges at multiple levels: lack of clean water and uninterrupted power supply, high environmental temperatures and humidity, dust, inexperienced and poorly trained staff, and a variable supply of consumables (often of poor quality). To deal with this at a base level, one should be very careful in selecting culture media. It is recommended to look for products supported by the national reference laboratory that are being distributed by an in-country supplier. Correct storage is key, as is appropriate preparation and waste management. Centralized media acquisition has been advocated for LMICs, a role that can be taken up by the national reference laboratories, next to guidance and support of the local laboratories. In addition, there is an important role in tropicalization and customization of culture media formulations for private in vitro diagnostic manufacturers, who are often still unfamiliar with the LMIC market and the plethora of bacteriology products. IMPLICATION The present narrative review will assist clinical microbiology laboratories in LMICs to establish best practices for handling culture media by defining quality, regulatory and research paths.
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Affiliation(s)
- Jeanne Orekan
- Clinical Microbiology, Centre National Hospitalier Universitaire Hubert Koutoukou Maga, Cotonou, Benin
| | - Barbara Barbé
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
| | - Sopheap Oeng
- Laboratory Department, Diagnostic Microbiology Development Program, Phnom Penh, Cambodia
| | - Jean-Baptiste Ronat
- Mini-Lab Project, Médecins Sans Frontières, Paris, France; Team ReSIST, INSERM U1184, School of Medicine University Paris-Saclay, France; Bacteriology-Hygiene Unit, Assistance Publique - Hôpitaux de Paris, Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Joanne Letchford
- Laboratory Department, Diagnostic Microbiology Development Program, Phnom Penh, Cambodia
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Dissou Affolabi
- Clinical Microbiology, Centre National Hospitalier Universitaire Hubert Koutoukou Maga, Cotonou, Benin
| | - Liselotte Hardy
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
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Qiao N, Fan X, Hu S, Zhang X, Wang L, Du Y, Wang L, Zhang X, Yu D. Bacterial cellulose as an oleaginous yeast cell carrier for soybean oil refinery effluent treatment and pyrolysis oil production. Bioprocess Biosyst Eng 2021; 44:661-671. [PMID: 33211199 DOI: 10.1007/s00449-020-02476-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 11/03/2020] [Indexed: 11/25/2022]
Abstract
Bacterial cellulose produced from soybean oil refinery effluent is a good immobilization carrier because of the large pores in its fiber network, its high water-holding capacity, and its good biocompatibility. In this study, it was applied to immobilization of oleaginous yeasts for treating soybean oil refinery effluent. The immobilization percentage reached 50%, and the removal of chemical oxygen demand and oil content reached 92.1% and 93.1%, respectively, during dynamic immobilization using a mass percentage of bacterial cellulose of 30% and an immobilization time of 24 h, which were significantly higher than those of free oleaginous yeasts or yeasts immobilized by bacterial cellulose from rich medium. The immobilized oleaginous yeasts facilitated the recovery of the yeasts and effectively treated three batches of soybean oil refinery effluent. The immobilized oleaginous yeasts recovered after soybean oil refinery effluent treatment were pyrolyzed to produce bio-oil, which contributed to more alkanes and a higher calorific value of bio-oil in the pyrolysis products as compared to those of free oleaginous yeasts. As bacterial cellulose used as an oleaginous yeast cell carrier is produced from soybean oil refinery effluent, no waste of immobilization materials is involved and an efficient waste-into-oil bioprocess is developed.
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Affiliation(s)
- Nan Qiao
- School of Civil Engineering and Architecture, Northeast Electric Power University, Jilin, 132012, China
| | - Xue Fan
- School of Civil Engineering and Architecture, Northeast Electric Power University, Jilin, 132012, China
- School of Resources and Environmental Engineering, Jilin Institute of Chemical Technology, Jilin, 132022, China
| | - Shuang Hu
- Sci-Tech Center for Clean Conversion and High-Valued Utilization of Biomass, Jilin Province, Northeast Electric Power University, Jilin, 132012, Jilin, China
| | - Xiuzhen Zhang
- Sci-Tech Center for Clean Conversion and High-Valued Utilization of Biomass, Jilin Province, Northeast Electric Power University, Jilin, 132012, Jilin, China
| | - Ling Wang
- Sci-Tech Center for Clean Conversion and High-Valued Utilization of Biomass, Jilin Province, Northeast Electric Power University, Jilin, 132012, Jilin, China
| | - Yundi Du
- School of Civil Engineering and Architecture, Northeast Electric Power University, Jilin, 132012, China
| | - Lei Wang
- Sci-Tech Center for Clean Conversion and High-Valued Utilization of Biomass, Jilin Province, Northeast Electric Power University, Jilin, 132012, Jilin, China
| | - Xiaojun Zhang
- Sci-Tech Center for Clean Conversion and High-Valued Utilization of Biomass, Jilin Province, Northeast Electric Power University, Jilin, 132012, Jilin, China.
| | - Dayu Yu
- Sci-Tech Center for Clean Conversion and High-Valued Utilization of Biomass, Jilin Province, Northeast Electric Power University, Jilin, 132012, Jilin, China.
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9
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Blanco Parte FG, Santoso SP, Chou CC, Verma V, Wang HT, Ismadji S, Cheng KC. Current progress on the production, modification, and applications of bacterial cellulose. Crit Rev Biotechnol 2020; 40:397-414. [PMID: 31937141 DOI: 10.1080/07388551.2020.1713721] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adoption of biomass for the development of biobased products has become a routine agenda in evolutionary metabolic engineering. Cellulose produced by bacteria is a "rising star" for this sustainable development. Unlike plant cellulose, bacterial cellulose (BC) shows several unique properties like a high degree of crystallinity, high purity, high water retention, high mechanical strength, and enhanced biocompatibility. Favored with those extraordinary properties, BC could serve as ideal biomass for the development of various industrial products. However, a low yield and the requirement for large growth media have been a persistent challenge in mass production of BC. A significant number of techniques has been developed in achieving efficient BC production. This includes the modification of bioreactors, fermentation parameters, and growth media. In this article, we summarize progress in metabolic engineering in order to solve BC growth limitation. This article emphasizes current engineered BC production by using various bioreactors, as well as highlighting the structure of BC fermented by different types of engineered-bioreactors. The comprehensive overview of the future applications of BC, aims to provide readers with insight into new economic opportunities of BC and their modifiable properties for various industrial applications. Modifications in chemical composition, structure, and genetic regulation, which preceded the advancement of BC applications, were also emphasized.
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Affiliation(s)
- Francisco German Blanco Parte
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Shella Permatasari Santoso
- Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Surabaya, Indonesia.,Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
| | - Chih-Chan Chou
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Vivek Verma
- Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India.,Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
| | - Hsueh-Ting Wang
- Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Suryadi Ismadji
- Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Surabaya, Indonesia.,Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
| | - Kuan-Chen Cheng
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan.,Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
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Raghavendran V, Asare E, Roy I. Bacterial cellulose: Biosynthesis, production, and applications. Adv Microb Physiol 2020; 77:89-138. [PMID: 34756212 DOI: 10.1016/bs.ampbs.2020.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Bacterial cellulose (BC) is a natural polymer produced by the acetic acid producing bacterium and has gathered much interest over the last decade for its biomedical and biotechnological applications. Unlike the plant derived cellulose nanofibres, which require pretreatment to deconstruct the recalcitrant lignocellulosic network, BC are 100% pure, and are extruded by cells as nanofibrils. Moreover, these nanofibrils can be converted to macrofibers that possess excellent material properties, surpassing even the strength of steel, and can be used as substitutes for fossil fuel derived synthetic fibers. The focus of the review is to present the fundamental long-term research on the influence of environmental factors on the organism's BC production capabilities, the production methods that are available for scaling up/scaled-up processes, and its use as a bulk commodity or for biomedical applications.
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Affiliation(s)
- Vijayendran Raghavendran
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom
| | - Emmanuel Asare
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom
| | - Ipsita Roy
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom.
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Vilela C, Oliveira H, Almeida A, Silvestre AJ, Freire CS. Nanocellulose-based antifungal nanocomposites against the polymorphic fungus Candida albicans. Carbohydr Polym 2019; 217:207-216. [DOI: 10.1016/j.carbpol.2019.04.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 10/27/2022]
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12
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Vilela C, Moreirinha C, Domingues EM, Figueiredo FML, Almeida A, Freire CSR. Antimicrobial and Conductive Nanocellulose-Based Films for Active and Intelligent Food Packaging. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E980. [PMID: 31284559 PMCID: PMC6669550 DOI: 10.3390/nano9070980] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 06/30/2019] [Accepted: 07/03/2019] [Indexed: 01/18/2023]
Abstract
Bacterial nanocellulose (BNC) is becoming an important substrate for engineering multifunctional nanomaterials with singular and tunable properties for application in several domains. Here, antimicrobial conductive nanocomposites composed of poly(sulfobetaine methacrylate) (PSBMA) and BNC were fabricated as freestanding films for application in food packaging. The nanocomposite films were prepared through the one-pot polymerization of sulfobetaine methacrylate (SBMA) inside the BNC nanofibrous network and in the presence of poly(ethylene glycol) diacrylate as cross-linking agent. The ensuing films are macroscopically homogeneous, more transparent than pristine BNC, and present thermal stability up to 265 °C in a nitrogen atmosphere. Furthermore, the films have good mechanical performance (Young's modulus ≥ 3.1 GPa), high water-uptake capacity (450-559%) and UV-blocking properties. The zwitterion film with 62 wt.% cross-linked PSBMA showed bactericidal activity against Staphylococcus aureus (4.3-log CFU mL-1 reduction) and Escherichia coli (1.1-log CFU mL-1 reduction), and proton conductivity ranging between 1.5 × 10-4 mS cm-1 (40 °C, 60% relative humidity (RH)) and 1.5 mS cm-1 (94 °C, 98% RH). Considering the current set of properties, PSBMA/BNC nanocomposites disclose potential as films for active food packaging, due to their UV-barrier properties, moisture scavenging ability, and antimicrobial activity towards pathogenic microorganisms responsible for food spoilage and foodborne illness; and also for intelligent food packaging, due to the proton motion relevant for protonic-conduction humidity sensors that monitor food humidity levels.
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Affiliation(s)
- Carla Vilela
- Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Catarina Moreirinha
- Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Eddy M Domingues
- Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Filipe M L Figueiredo
- Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Adelaide Almeida
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Carmen S R Freire
- Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
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Vilela C, Moreirinha C, Almeida A, Silvestre AJD, Freire CSR. Zwitterionic Nanocellulose-Based Membranes for Organic Dye Removal. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E1404. [PMID: 31052184 PMCID: PMC6539420 DOI: 10.3390/ma12091404] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 12/19/2022]
Abstract
The development of efficient and environmentally-friendly nanomaterials to remove contaminants and pollutants (including harmful organic dyes) ravaging water sources is of major importance. Herein, zwitterionic nanocomposite membranes consisting of cross-linked poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and bacterial nanocellulose (BNC) were prepared and tested as tools for water remediation. These nanocomposite membranes fabricated via the one-pot polymerization of the zwitterionic monomer, 2-methacryloyloxyethyl phosphorylcholine, within the BNC three-dimensional porous network, exhibit thermal stability up to 250 °C, good mechanical performance (Young's modulus ≥ 430 MPa) and high water-uptake capacity (627%-912%) in different pH media. Moreover, these zwitterionic membranes reduced the bacterial concentration of both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) pathogenic bacteria with maxima of 4.3- and 1.8-log CFU reduction, respectively, which might be a major advantage in reducing or avoiding bacterial growth in contaminated water. The removal of two water-soluble model dyes, namely methylene blue (MB, cationic) and methyl orange (MO, anionic), from water was also assessed and the results demonstrated that both dyes were successfully removed under the studied conditions, reaching a maximum of ionic dye adsorption of ca. 4.4-4.5 mg g-1. This combination of properties provides these PMPC/BNC nanocomposites with potential for application as antibacterial bio-based adsorbent membranes for water remediation of anionic and cationic dyes.
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Affiliation(s)
- Carla Vilela
- Department of Chemistry, CICECO ⁻ Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Catarina Moreirinha
- Department of Chemistry, CICECO ⁻ Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Adelaide Almeida
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Armando J D Silvestre
- Department of Chemistry, CICECO ⁻ Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Carmen S R Freire
- Department of Chemistry, CICECO ⁻ Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
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Fu S, Tu J, Rahman MM, Tian H, Xiao P, Liu Y. Precise feeding of probiotics in the treatment of edwardsiellosis by accurate estimation of Edwardsiella tarda. ANN MICROBIOL 2018. [DOI: 10.1007/s13213-018-1371-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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15
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Complete genome analysis of Gluconacetobacter xylinus CGMCC 2955 for elucidating bacterial cellulose biosynthesis and metabolic regulation. Sci Rep 2018; 8:6266. [PMID: 29674724 PMCID: PMC5908849 DOI: 10.1038/s41598-018-24559-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/03/2018] [Indexed: 01/04/2023] Open
Abstract
Complete genome sequence of Gluconacetobacter xylinus CGMCC 2955 for fine control of bacterial cellulose (BC) synthesis is presented here. The genome, at 3,563,314 bp, was found to contain 3,193 predicted genes without gaps. There are four BC synthase operons (bcs), among which only bcsI is structurally complete, comprising bcsA, bcsB, bcsC, and bcsD. Genes encoding key enzymes in glycolytic, pentose phosphate, and BC biosynthetic pathways and in the tricarboxylic acid cycle were identified. G. xylinus CGMCC 2955 has a complete glycolytic pathway because sequence data analysis revealed that this strain possesses a phosphofructokinase (pfk)-encoding gene, which is absent in most BC-producing strains. Furthermore, combined with our previous results, the data on metabolism of various carbon sources (monosaccharide, ethanol, and acetate) and their regulatory mechanism of action on BC production were explained. Regulation of BC synthase (Bcs) is another effective method for precise control of BC biosynthesis, and cyclic diguanylate (c-di-GMP) is the key activator of BcsA–BcsB subunit of Bcs. The quorum sensing (QS) system was found to positively regulate phosphodiesterase, which decomposed c-di-GMP. Thus, in this study, we demonstrated the presence of QS in G. xylinus CGMCC 2955 and proposed a possible regulatory mechanism of QS action on BC production.
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Ombelet S, Ronat JB, Walsh T, Yansouni CP, Cox J, Vlieghe E, Martiny D, Semret M, Vandenberg O, Jacobs J. Clinical bacteriology in low-resource settings: today's solutions. THE LANCET. INFECTIOUS DISEASES 2018. [PMID: 29519767 DOI: 10.1016/s1473-3099(18)30093-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Low-resource settings are disproportionately burdened by infectious diseases and antimicrobial resistance. Good quality clinical bacteriology through a well functioning reference laboratory network is necessary for effective resistance control, but low-resource settings face infrastructural, technical, and behavioural challenges in the implementation of clinical bacteriology. In this Personal View, we explore what constitutes successful implementation of clinical bacteriology in low-resource settings and describe a framework for implementation that is suitable for general referral hospitals in low-income and middle-income countries with a moderate infrastructure. Most microbiological techniques and equipment are not developed for the specific needs of such settings. Pending the arrival of a new generation diagnostics for these settings, we suggest focus on improving, adapting, and implementing conventional, culture-based techniques. Priorities in low-resource settings include harmonised, quality assured, and tropicalised equipment, consumables, and techniques, and rationalised bacterial identification and testing for antimicrobial resistance. Diagnostics should be integrated into clinical care and patient management; clinically relevant specimens must be appropriately selected and prioritised. Open-access training materials and information management tools should be developed. Also important is the need for onsite validation and field adoption of diagnostics in low-resource settings, with considerable shortening of the time between development and implementation of diagnostics. We argue that the implementation of clinical bacteriology in low-resource settings improves patient management, provides valuable surveillance for local antibiotic treatment guidelines and national policies, and supports containment of antimicrobial resistance and the prevention and control of hospital-acquired infections.
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Affiliation(s)
- Sien Ombelet
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
| | | | | | - Cedric P Yansouni
- JD MacLean Centre for Tropical Diseases, McGill University Health Centre, Montreal, QC, Canada
| | - Janneke Cox
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Erika Vlieghe
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of General Internal Medicine, Infectious and Tropical Diseases, Antwerp University Hospital, Antwerp, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Delphine Martiny
- Department of Microbiology, LHUB-ULB, Pôle Hospitalier Universitaire de Bruxelles, Brussels, Belgium
| | - Makeda Semret
- JD MacLean Centre for Tropical Diseases, McGill University Health Centre, Montreal, QC, Canada; St Mary's Hospital Centre, Montreal, QC, Canada
| | - Olivier Vandenberg
- Department of Microbiology, LHUB-ULB, Pôle Hospitalier Universitaire de Bruxelles, Brussels, Belgium; Center for Environmental Health and Occupational Health, Public Health School, Université Libre de Bruxelles, Brussels, Belgium
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
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Liu M, Li S, Xie Y, Jia S, Hou Y, Zou Y, Zhong C. Enhanced bacterial cellulose production by Gluconacetobacter xylinus via expression of Vitreoscilla hemoglobin and oxygen tension regulation. Appl Microbiol Biotechnol 2017; 102:1155-1165. [PMID: 29199354 DOI: 10.1007/s00253-017-8680-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 11/23/2017] [Indexed: 10/18/2022]
Abstract
Oxygen plays a key role during bacterial cellulose (BC) biosynthesis by Gluconacetobacter xylinus. In this study, the Vitreoscilla hemoglobin (VHb)-encoding gene vgb, which has been widely applied to improve cell survival during hypoxia, was heterologously expressed in G. xylinus via the pBla-VHb-122 plasmid. G. xylinus and G. xylinus-vgb + were statically cultured under hypoxic (10 and 15% oxygen tension in the gaseous phase), atmospheric (21%), and oxygen-enriched conditions (40 and 80%) to investigate the effect of oxygen on cell growth and BC production. Irrespective of vgb expression, we found that cell density increased with oxygen tension (10-80%) during the exponential growth phase but plateaued to the same value in the stationary phase. In contrast, BC production was found to significantly increase at lower oxygen tensions. In addition, we found that BC production at oxygen tensions of 10 and 15% was 26.5 and 58.6% higher, respectively, in G. xylinus-vgb + than that in G. xylinus. The maximum BC yield and glucose conversion rate, of 4.3 g/L and 184.7 mg/g, respectively, were observed in G. xylinus-vgb + at an oxygen tension of 15%. Finally, BC characterization suggested that hypoxic conditions enhance BC's mass density, Young's modulus, and thermostability, with G. xylinus-vgb + synthesizing softer BC than G. xylinus under hypoxia as a result of a decreased Young's modulus. These results will facilitate the use of static culture for the production of BC.
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Affiliation(s)
- Miao Liu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Siqi Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Yongzhen Xie
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Shiru Jia
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Ying Hou
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Yang Zou
- Tianjin Jialihe Livestock Group Co., Ltd, Jin Wei Road, Beichen District, Tianjin, 300402, People's Republic of China
| | - Cheng Zhong
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
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Jaeger PA, McElfresh C, Wong LR, Ideker T. Beyond Agar: Gel Substrates with Improved Optical Clarity and Drug Efficiency and Reduced Autofluorescence for Microbial Growth Experiments. Appl Environ Microbiol 2015; 81:5639-49. [PMID: 26070672 PMCID: PMC4510171 DOI: 10.1128/aem.01327-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/07/2015] [Indexed: 11/20/2022] Open
Abstract
Agar, a seaweed extract, has been the standard support matrix for microbial experiments for over a century. Recent developments in high-throughput genetic screens have created a need to reevaluate the suitability of agar for use as colony support, as modern robotic printing systems now routinely spot thousands of colonies within the area of a single microtiter plate. Identifying optimal biophysical, biochemical, and biological properties of the gel support matrix in these extreme experimental conditions is instrumental to achieving the best possible reproducibility and sensitivity. Here we systematically evaluate a range of gelling agents by using the yeast Saccharomyces cerevisiae as a model microbe. We find that carrageenan and Phytagel have superior optical clarity and reduced autofluorescence, crucial for high-resolution imaging and fluorescent reporter screens. Nutrient choice and use of refined Noble agar or pure agarose reduce the effective dose of numerous selective drugs by >50%, potentially enabling large cost savings in genetic screens. Using thousands of mutant yeast strains to compare colony growth between substrates, we found no evidence of significant growth or nutrient biases between gel substrates, indicating that researchers could freely pick and choose the optimal gel for their respective application and experimental condition.
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Affiliation(s)
- Philipp A Jaeger
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, California, USA
| | - Cameron McElfresh
- Nanoengineering Program, University of California San Diego, La Jolla, California, USA
| | - Lily R Wong
- Bioengineering Program, University of California San Diego, La Jolla, California, USA
| | - Trey Ideker
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, California, USA
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Type IV pili mechanochemically regulate virulence factors in Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2015; 112:7563-8. [PMID: 26041805 DOI: 10.1073/pnas.1502025112] [Citation(s) in RCA: 262] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteria have evolved a wide range of sensing systems to appropriately respond to environmental signals. Here we demonstrate that the opportunistic pathogen Pseudomonas aeruginosa detects contact with surfaces on short timescales using the mechanical activity of its type IV pili, a major surface adhesin. This signal transduction mechanism requires attachment of type IV pili to a solid surface, followed by pilus retraction and signal transduction through the Chp chemosensory system, a chemotaxis-like sensory system that regulates cAMP production and transcription of hundreds of genes, including key virulence factors. Like other chemotaxis pathways, pili-mediated surface sensing results in a transient response amplified by a positive feedback that increases type IV pili activity, thereby promoting long-term surface attachment that can stimulate additional virulence and biofilm-inducing pathways. The methyl-accepting chemotaxis protein-like chemosensor PilJ directly interacts with the major pilin subunit PilA. Our results thus support a mechanochemical model where a chemosensory system measures the mechanically induced conformational changes in stretched type IV pili. These findings demonstrate that P. aeruginosa not only uses type IV pili for surface-specific twitching motility, but also as a sensor regulating surface-induced gene expression and pathogenicity.
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