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Fu Y, Liu X, Su Z, Wang P, Guo Q, Ma P. Arabinose Plays an Important Role in Regulating the Growth and Sporulation of Bacillus subtilis NCD-2. Int J Mol Sci 2023; 24:17472. [PMID: 38139303 PMCID: PMC10744016 DOI: 10.3390/ijms242417472] [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: 10/20/2023] [Revised: 11/22/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
A microbial fungicide developed from Bacillus subtilis NCD-2 has been registered for suppressing verticillium wilt in crops in China. Spores are the main ingredient of this fungicide and play a crucial role in suppressing plant disease. Therefore, increasing the number of spores of strain NCD-2 during fermentation is important for reducing the cost of the fungicide. In this study, five kinds of carbon sources were found to promote the metabolism of strain NCD-2 revealed via Biolog Phenotype MicroArray (PM) technology. L-arabinose showed the strongest ability to promote the growth and sporulation of strain NCD-2. L-arabinose increased the bacterial concentration and the sporulation efficiency of strain NCD-2 by 2.04 times and 1.99 times compared with D-glucose, respectively. Moreover, L-arabinose significantly decreased the autolysis of strain NCD-2. Genes associated with arabinose metabolism, sporulation, spore resistance to heat, and spore coat formation were significantly up-regulated, and genes associated with sporulation-delaying protein were significantly down-regulated under L-arabinose treatment. The deletion of msmX, which is involved in arabinose transport in the Bacillus genus, decreased growth and sporulation by 53.71% and 86.46% compared with wild-type strain NCD-2, respectively. Complementing the mutant strain by importing an intact msmX gene restored the strain's growth and sporulation.
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Affiliation(s)
- Yifan Fu
- College of Plant Protection, Agricultural University of Hebei, Baoding 071000, China;
- Key Laboratory of IPM on Crops in Northern Region of North China, Integrated Pest Management Innovation Centre of Hebei Province, Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Ministry of Agriculture and Rural Affairs of China, Baoding 071000, China; (X.L.); (Z.S.); (P.W.)
| | - Xiaomeng Liu
- Key Laboratory of IPM on Crops in Northern Region of North China, Integrated Pest Management Innovation Centre of Hebei Province, Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Ministry of Agriculture and Rural Affairs of China, Baoding 071000, China; (X.L.); (Z.S.); (P.W.)
| | - Zhenhe Su
- Key Laboratory of IPM on Crops in Northern Region of North China, Integrated Pest Management Innovation Centre of Hebei Province, Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Ministry of Agriculture and Rural Affairs of China, Baoding 071000, China; (X.L.); (Z.S.); (P.W.)
| | - Peipei Wang
- Key Laboratory of IPM on Crops in Northern Region of North China, Integrated Pest Management Innovation Centre of Hebei Province, Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Ministry of Agriculture and Rural Affairs of China, Baoding 071000, China; (X.L.); (Z.S.); (P.W.)
| | - Qinggang Guo
- Key Laboratory of IPM on Crops in Northern Region of North China, Integrated Pest Management Innovation Centre of Hebei Province, Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Ministry of Agriculture and Rural Affairs of China, Baoding 071000, China; (X.L.); (Z.S.); (P.W.)
| | - Ping Ma
- Key Laboratory of IPM on Crops in Northern Region of North China, Integrated Pest Management Innovation Centre of Hebei Province, Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Ministry of Agriculture and Rural Affairs of China, Baoding 071000, China; (X.L.); (Z.S.); (P.W.)
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Rai S, Mago Y, Aggarwal G, Yadav A, Tewari S. Liquid Bioformulation: A Trending Approach Towards Achieving Sustainable Agriculture. Mol Biotechnol 2023:10.1007/s12033-023-00901-0. [PMID: 37923941 DOI: 10.1007/s12033-023-00901-0] [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: 04/17/2023] [Accepted: 09/10/2023] [Indexed: 11/06/2023]
Abstract
The human population is expanding at an exponential rate, and has created a great surge in the demand for food production. To intensify the rate of crop production, there is a tremendous usage of chemical pesticides and fertilizers. The practice of using these chemicals to enhance crop productivity has resulted in the degradation of soil fertility, leading to the depletion of native soil microflora. The constant application of these hazardous chemicals in the soil possesses major threat to humans and animals thereby impacting the agroecosystem severely. Hence, it is very important to hunt for certain new alternatives for enhancing crop productivity in an eco-friendly manner by using the microbial bioformulations. Microbial bioformulations can be mainly divided into two types: solid and liquid. There is a lot of information available on the subject of solid bioformulation, but the concept of liquid bioformulation is largely ignored. This article focuses on the diverse spectrum of liquid bioformulation pertaining to the market capture, its different types, potency of the product, mode of usage, and the limitations encountered. Also the authors have tried to include all the strategies required for sensitizing and making liquid bioformulation approach cost effective and as a greener strategy to succeed in developing countries.
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Affiliation(s)
- Samaksh Rai
- Department of Life Sciences, J.C. Bose University of Science and Technology, YMCA, NH-2, Sector-6, Mathura Road, Faridabad, Haryana, 121006, India
| | - Yashika Mago
- Department of Life Sciences, J.C. Bose University of Science and Technology, YMCA, NH-2, Sector-6, Mathura Road, Faridabad, Haryana, 121006, India
| | - Geetika Aggarwal
- Department of Life Sciences, J.C. Bose University of Science and Technology, YMCA, NH-2, Sector-6, Mathura Road, Faridabad, Haryana, 121006, India
| | - Anjali Yadav
- Department of Life Sciences, J.C. Bose University of Science and Technology, YMCA, NH-2, Sector-6, Mathura Road, Faridabad, Haryana, 121006, India
| | - Sakshi Tewari
- Department of Life Sciences, J.C. Bose University of Science and Technology, YMCA, NH-2, Sector-6, Mathura Road, Faridabad, Haryana, 121006, India.
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Šimunović K, Sahin O, Erega A, Štefanič P, Zhang Q, Mandic Mulec I, Smole Možina S, Klančnik A. Bacillus subtilis PS-216 Spores Supplemented in Broiler Chicken Drinking Water Reduce Campylobacter jejuni Colonization and Increases Weight Gain. Front Microbiol 2022; 13:910616. [PMID: 35875550 PMCID: PMC9304915 DOI: 10.3389/fmicb.2022.910616] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Campylobacter jejuni is the leading cause of bacterial gastroenteritis, or campylobacteriosis, in humans worldwide, and poultry serves as a major source of infection. To reduce the risk associated with C. jejuni transmission via poultry meat, effective interventions during poultry production are needed, and the use of probiotics is a promising approach. In this study, 15 Bacillus subtilis strains were initially screened for their anti-Campylobacter activities. B. subtilis PS-216 strain demonstrated the best anti-Campylobacter activity against 15 C. jejuni isolates when examined using in vitro co-cultures. To evaluate the suitability of B. subtilis PS-216 for probiotic use, its susceptibility to eight clinically important antimicrobials and simulated gastric conditions was investigated. B. subtilis PS-216 was sensitive to all of the tested antibiotics. Although vegetative cells were sensitive to gastric conditions, B. subtilis PS-216 spores were highly resistant. We further evaluated the use of a B. subtilis PS-216 spore preparation (2.5 × 106 CFU/mL water) to prevent and/or reduce C. jejuni colonization in broiler chickens in vivo. Compared to the untreated group, significantly lower Campylobacter counts were detected in caeca of broilers continuously treated with B. subtilis PS-216 spores in their drinking water. Furthermore, broilers continuously treated with B. subtilis PS-216 spores showed improved weight gain, compared to the control group. Together, these results demonstrate the potential of B. subtilis PS-216 for use in poultry to reduce C. jejuni colonization and improve weight gain.
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Affiliation(s)
- Katarina Šimunović
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department of Microbiology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Orhan Sahin
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Andi Erega
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department of Microbiology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Polonca Štefanič
- Department of Microbiology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Qijing Zhang
- Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Ines Mandic Mulec
- Department of Microbiology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Sonja Smole Možina
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Anja Klančnik
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- *Correspondence: Anja Klančnik,
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Recent Advances in the Physiology of Spore Formation for Bacillus Probiotic Production. Probiotics Antimicrob Proteins 2020; 11:731-747. [PMID: 30515722 DOI: 10.1007/s12602-018-9492-x] [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: 12/20/2022]
Abstract
Spore-forming probiotic bacteria have received a wide and constantly increasing scientific and commercial interest. Among them, Bacillus species are the most studied and well-characterized Gram-positive bacteria. The use of bacilli as probiotic products is expanding especially rapidly due to their inherent ability to form endospores with unique survivability and tolerance to extreme environments and to produce a large number of valuable metabolites coupled with their bio-therapeutic potential demonstrating immune stimulation, antimicrobial activities and competitive exclusion. Ease of Bacillus spp. production and stability during processing and storage make them a suitable candidate for commercial manufacture of novel foods or dietary supplements for human and animal feeds for livestock, especially in the poultry and aquaculture industries. Therefore, the development of low-cost and competitive technologies for the production of spore-forming probiotic bacteria through understanding physiological peculiarities and mechanisms determining the growth and spore production by Bacillus spp. became necessary. This review summarizes the recent literature and our own data on the physiology of bacilli growth and spore production in the submerged and solid-state fermentation conditions, focusing on the common characteristics and unique properties of individual bacteria as well as on several approaches providing enhanced spore formation.
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A metabolomic approach to understand the solid-state fermentation of okara using Bacillus subtilis WX-17 for enhanced nutritional profile. AMB Express 2019; 9:60. [PMID: 31055712 PMCID: PMC6500514 DOI: 10.1186/s13568-019-0786-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 04/25/2019] [Indexed: 12/20/2022] Open
Abstract
Okara is a major agro-waste produced from the soybean industry. To hydrolyze the okara and enable nutrient release, a strategy to valorize okara using solid-state fermentation with food grade Bacillus subtilis (B. subtilis) WX-17 was carried out. The study showed that fermentation of okara with B. subtilis WX-17 improved its overall nutritional content. The total amino acids content increased from 3.04 ± 0.14 mg/g in unfermented okara to 5.41 ± 1.21 mg/g in okara fermented with B. subtilis WX-17. Total fatty acids content increased from 153.04 ± 5.10 to 166.78 ± 2.41 mg/g okara, after fermentation. Antioxidant content (DPPH) also increased by 6.4 times after fermentation. To gain insight into the mechanism, gas chromatography–mass spectrometry analysis was carried out. In total, 49 metabolites were detected, which could be classified mainly into carbohydrates, TCA cycle metabolites, amino acids and fatty acids. The decrease in carbohydrate metabolites, showed that glycolysis was upregulated. This would have provided the energy and metabolic flux towards the amino acid and fatty acid pathway. This is also in line with the increased amino acids and fatty acid production seen in okara fermented with B. subtilis WX-17. The findings of this work demonstrated the potential of using B. subtilis WX-17 fermentation, to enhance the nutritional profile of okara. This could serve as a potential low-cost animal feed or incorporated into the human diet.
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Bressuire-Isoard C, Broussolle V, Carlin F. Sporulation environment influences spore properties in Bacillus: evidence and insights on underlying molecular and physiological mechanisms. FEMS Microbiol Rev 2018; 42:614-626. [DOI: 10.1093/femsre/fuy021] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/16/2018] [Indexed: 02/07/2023] Open
Affiliation(s)
- Christelle Bressuire-Isoard
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
| | - Véronique Broussolle
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
| | - Frédéric Carlin
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
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Spacapan M, Danevčič T, Mandic-Mulec I. ComX-Induced Exoproteases Degrade ComX in Bacillus subtilis PS-216. Front Microbiol 2018; 9:105. [PMID: 29449835 PMCID: PMC5799266 DOI: 10.3389/fmicb.2018.00105] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/17/2018] [Indexed: 11/13/2022] Open
Abstract
Gram-positive bacteria use peptides as auto-inducing (AI) signals to regulate the production of extracellular enzymes (e.g., proteases). ComX is an AI peptide, mostly known for its role in the regulation of bacterial competence and surfactant production in Bacillus subtilis. These two traits are regulated accordingly to the bacterial population size, thus classifying ComX as a quorum sensing signal. ComX also indirectly regulates exoprotease production through the intermediate transcriptional regulator DegQ. We here use this peptide-based AI system (the ComQXPA system) as a model to address exoprotease regulation by ComX in biofilms. We also investigate the potential of ComX regulated proteases to degrade the ComX AI peptide. Results indicate that ComX indeed induces the expression of aprE, the gene for the major serine protease subtilisin, and stimulates overall exoprotease production in biofilms of B. subtilis PS-216 and several other B. subtilis soil isolates. We also provide evidence that these exoproteases can degrade ComX. The ComX biological activity decay is reduced in the spent media of floating biofilms with low proteolytic activity found in the comP and degQ mutants. ComX biological activity decay can be restored by the addition of subtilisin to such media. In contrast, inhibition of metalloproteases by EDTA reduces ComX biological activity decay. This suggests that both serine and metalloproteases, which are induced by ComX, are ultimately capable of degrading this signaling peptide. This work brings novel information on regulation of exoproteases in B. subtilis floating biofilms and reveals that these proteolytic enzymes degrade the AI signaling peptide ComX, which is also a major determinant of their expression in biofilms.
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Affiliation(s)
- Mihael Spacapan
- Chair of Microbiology, Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Tjaša Danevčič
- Chair of Microbiology, Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Ines Mandic-Mulec
- Chair of Microbiology, Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
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8
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Calvo H, Marco P, Blanco D, Oria R, Venturini M. Potential of a new strain of Bacillus amyloliquefaciens BUZ-14 as a biocontrol agent of postharvest fruit diseases. Food Microbiol 2017; 63:101-110. [DOI: 10.1016/j.fm.2016.11.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 10/28/2016] [Accepted: 11/07/2016] [Indexed: 11/26/2022]
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9
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Extraction of Bacillus endospores from water, apple juice concentrate, raw milk and lettuce rinse solutions using tangential flow filtration. Food Control 2013. [DOI: 10.1016/j.foodcont.2013.01.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Soybean molasses-based bioindicator system for monitoring sterilization process: Designing and performance evaluation. BIOTECHNOL BIOPROC E 2013. [DOI: 10.1007/s12257-012-0356-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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11
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Huo Z, Zhang N, Xu Z, Li S, Zhang Q, Qiu M, Yong X, Huang Q, Zhang R, Shen QR. Optimization of survival and spore formation of Paenibacillus polymyxa SQR-21 during bioorganic fertilizer storage. BIORESOURCE TECHNOLOGY 2012; 108:190-195. [PMID: 22264433 DOI: 10.1016/j.biortech.2011.12.137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 11/29/2011] [Accepted: 12/27/2011] [Indexed: 05/31/2023]
Abstract
The effects of storage temperature (20, 30 and 40 °C), inoculum type (pure spores, an equal mix of spores and vegetative cells and pure vegetative cells) and water content (20%, 30% and 40%) on the survival and spore formation of the biocontrol agent, Paenibacillus polymyxa SQR-21, in a bioorganic fertilizer were modeled in a 3×3×3 factorial design. Bacterial and spore populations were monitored by plate count and fluorescence in situ hybridization (FISH). Temperature significantly affected survival of inoculants after storage for 60 days. Populations were 1.48 (plate counting) or 1.71 (FISH) times greater when stored at 20 °C compared to 40 °C. Inoculation of the fertilizer with pure spores led to the highest spore formation percentage (67.6% for plate counting, 94.2% for FISH). This study provides useful information for preservation of bioorganic fertilizer.
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Affiliation(s)
- Zhenhua Huo
- Jiangsu Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing 210095, China
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Huo Z, Zhang N, Raza W, Huang X, Yong X, Liu Y, Wang D, Li S, Shen Q, Zhang R. Comparison of the spores of Paenibacillus polymyxa prepared at different temperatures. Biotechnol Lett 2012; 34:925-33. [DOI: 10.1007/s10529-012-0853-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Accepted: 01/05/2012] [Indexed: 10/14/2022]
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Das S, Sen R. Kinetic modeling of sporulation and product formation in stationary phase by Bacillus coagulans RK-02 vis-à-vis other Bacilli. BIORESOURCE TECHNOLOGY 2011; 102:9659-9667. [PMID: 21852126 DOI: 10.1016/j.biortech.2011.07.067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 07/17/2011] [Accepted: 07/19/2011] [Indexed: 05/31/2023]
Abstract
A logistic kinetic model was derived and validated to characterize the dynamics of a sporogenous bacterium in stationary phase with respect to sporulation and product formation. The kinetic constants as determined using this model are particularly important for describing intrinsic properties of a sporogenous bacterial culture in stationary phase. Non-linear curve fitting of the experimental data into the mathematical model showed very good correlation with the predicted values for sporulation and lipase production by Bacillus coagulans RK-02 culture in minimal media. Model fitting of literature data of sporulation and product (protease and amylase) formation in the stationary phase by some other Bacilli and comparison of the results of model fitting with those of Bacillus coagulans helped validate the significance and robustness of the developed kinetic model.
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Affiliation(s)
- Subhasish Das
- Department of Biotechnology, Indian Institute of Technology, Kharagpur 721 302, West Bengal, India.
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Burgess SA, Lindsay D, Flint SH. Thermophilic bacilli and their importance in dairy processing. Int J Food Microbiol 2010; 144:215-25. [DOI: 10.1016/j.ijfoodmicro.2010.09.027] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 08/15/2010] [Accepted: 09/25/2010] [Indexed: 11/24/2022]
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Namvar A, Warriner K. Microbial imprinted polypyrrole/poly(3-methylthiophene) composite films for the detection of Bacillus endospores. Biosens Bioelectron 2006; 22:2018-24. [PMID: 17008088 DOI: 10.1016/j.bios.2006.08.039] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 08/23/2006] [Accepted: 08/25/2006] [Indexed: 10/24/2022]
Abstract
The fabrication of Bacillus subtilis endospore imprinted conducting polymer films and subsequent electrochemical detection of bound spores is reported. Imprinted films were prepared by absorbing spores on the surface of glassy carbon electrodes upon which a polypyrrole, followed by a poly(3-methylthiophene), layer were electrochemically deposited. Spore template release was achieved through soaking the modified electrode in DMSO. Binding of endospores to imprinted films could be detected via impedance spectroscopy by monitoring changes in Y'' (susceptance) using Mn(II)Cl2 (0.5M pH 3) as the supporting electrolyte. Here, the change in Y'' could be correlated to spore densities between 10(4) and 10(7)cfu/ml. More sensitive detection of absorbed spores was achieved by following endospore germination via changes in film charge as measured using cyclic voltammetry. Here, imprinted films were submerged in spore suspensions to permit absorption, heat activated at 70 degrees C for 10 min prior to transferring to an electrochemical cell containing germination activators. By using the assay format it was possible to detect 10(2)cfu/ml. The observed changes in film charge could be attributed to the interaction of the supporting conducting polymer with dipicolinic acid (DPA) and other constituents released from the core in the course of germination. In all cases, it was not possible to regenerate the imprinted films without losing electrode response. In summary, the study has provided proof-of-concept for fabricating microbial imprinted films using conducting polymers.
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Affiliation(s)
- Azadeh Namvar
- Department of Food Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Monteiro SM, Clemente JJ, Henriques AO, Gomes RJ, Carrondo MJ, Cunha AE. A procedure for high-yield spore production by Bacillus subtilis. Biotechnol Prog 2006; 21:1026-31. [PMID: 16080679 DOI: 10.1021/bp050062z] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacillus subtilis spores have a number of potential applications, which include their use as probiotics and competitive exclusion agents to control zoonotic pathogens in animal production. The effect of cultivation conditions on Bacillus subtilis growth and sporulation was investigated in batch bioreactions performed at a 2-L scale. Studies of the cultivation conditions (pH, dissolved oxygen concentration, and media composition) led to an increase of the maximum concentration of vegetative cell from 2.6 x 10(9) to 2.2 x 10(10) cells mL(-)(1) and the spore concentration from 4.2 x 10(8) to 5.6 x 10(9) spores mL(-)(1). A fed-batch bioprocess was developed with the addition of a nutrient feeding solution using an exponential feeding profile obtained from the mass balance equations. Using the developed feeding profile, starting at the middle of the exponential growth phase and finishing in the late exponential phase, an increase of the maximum vegetative cell concentration and spore concentration up to 3.6 x 10(10) cells mL(-)(1) and 7.4 x 10(9) spores mL(-)(1), respectively, was obtained. Using the developed fed-batch bioreaction a 14-fold increase in the concentration of the vegetative cells was achieved. Moreover, the efficiency of sporulation under fed-batch bioreaction was 21%, which permitted a 19-fold increase in the final spore concentration, to a final value of 7.4 x 10(9) spores mL(-)(1). This represents a 3-fold increase relative to the highest reported value for Bacillus subtilis spore production.
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Affiliation(s)
- Sandra M Monteiro
- Instituto de Biologia Experimental e Tecnológica (IBET), Apartado 1, P-2781-901 Oeiras, Portugal
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Warriner K, Kolstad J, Rumsby P, Waites WM. Carton sterilization by u.v.-C excimer laser light: recovery of Bacillus subtilis spores on vegetable extracts and food simulation matrices. J Appl Microbiol 2002; 92:1051-7. [PMID: 12010545 DOI: 10.1046/j.1365-2672.2002.01641.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To determine the recovery of Bacillus subtilis spores loaded onto preformed cartons and irradiated with u.v.-excimer laser (248 nm) light. METHODS AND RESULTS Bacillus subtilis spores irradiated with u.v.-excimer laser light retained phase brightness, but were blocked at various stages of germination. In the presence of germinant, the majority of spores began to lose phase brightness but only after an extended lag period (ca 90 min). After 6 h ca 9% of the spores had elongated but failed to form new cells, approx. 12% had undergone partial phase darkening (grey spores), 15% remained phase bright whilst the remainder had turned fully phase dark but failed to elongate. No enhanced recovery of u.v.-treated spores (with intact or permeabilized coats) occurred in media containing hen egg white lysozyme or vegetable extracts (celery, carrot, swede or turnip). However, recovery did occur when irradiated spores were incubated for 26 d, semiaerobically, within cartons containing nutrient broth or milk. CONCLUSIONS The germination ability of B. subtilis spores is altered following u.v.-excimer laser treatment. Recovery of treated spores was found in liquid systems but not on agar plates supplemented with vegetable extracts or lysozyme. SIGNIFICANCE AND IMPACT OF THE STUDY The potential recovery of u.v.-excimer laser-treated spores in a range of carton-packed food systems requires further investigation.
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Affiliation(s)
- K Warriner
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Loughborough, Leicestershire, UK
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Warriner K, Rysstad G, Murden A, Rumsby P, Thomas D, Waites WM. Inactivation of Bacillus subtilis spores on aluminum and polyethylene preformed cartons by UV-excimer laser irradiation. J Food Prot 2000; 63:753-7. [PMID: 10852569 DOI: 10.4315/0362-028x-63.6.753] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The efficacy of UV KrF-excimer laser light (at 248 nm) to inactivate Bacillus subtilis spores loaded onto preformed cartons was found to be dependent on the interior carton coating and scheme by which the irradiation was applied. When the carton was held static during UV laser treatment, the majority of the dose was delivered to the base of the carton and to a lesser extent to the upper part of the pack. In this arrangement no irradiation of the interior sides of the carton was observed. A more even distribution of dose was achieved, however, by moving the carton within the laser beam during irradiation treatment. The distribution of UV was also found to be dependent on the type of carton interior coating. With aluminum cartons the dose measured was found to be significantly greater (P < 0.01) and more evenly distributed across the interior compared to when polyethylene packs were tested. Under optimized conditions no spore survivors were detected on aluminum cartons preloaded with 9.5 x l0 B. subtilis spores by applying a UV laser output dose of 160 J. In comparison, the same conditions only achieved a significantly lower (P < 0.01) reduction in spore numbers (log count reduction 4.2) when polyethylene cartons were used. This difference in lethality and UV distribution of laser light was associated with the higher internal reflection of photons with aluminum cartons. The suitability of UV-excimer lasers for sterilizing preformed cartons over traditional germicidal lamp-based methods is discussed.
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Affiliation(s)
- K Warriner
- Division of Food Sciences, School of Biological Sciences, University of Nottingham, Loughborough, Leicestershire, UK
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Warriner K, Rysstad G, Murden A, Rumsby P, Thomas D, Waites WM. Inactivation of Bacillus subtilis spores on packaging surfaces by u. v. excimer laser irradiation. J Appl Microbiol 2000; 88:678-85. [PMID: 10792527 DOI: 10.1046/j.1365-2672.2000.01015.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ultraviolet (u.v.) laser irradiation has been used to inactivate Bacillus subtilis spores deposited on to planar aluminium- and polyethylene-coated packaging surfaces. Kill kinetics were found to be diphasic, with an initial rapid inactivation phase followed by tailing. Although no definitive evidence was obtained, it is thought that spores located within packaging crevices/pores were primarily responsible for the observed tailing. Surviving spores were also found on the unexposed underside of cards and, to a lesser extent, within clumps. The log count reduction in B. subtilis was dependent on spore loading and total u.v. dose. In comparison, packaging surface composition, fluence (2-18 Jm-2) and frequency (40-150 Hz) had only a negligible effect. By irradiating boards carrying 106 spores, with a dose of 11.5 J cm-2, a log count reduction >5 was obtained. The mode of spore inactivation was primarily through DNA disruption. This was confirmed by the high sensitivity of spores lacking protective, small, acid-soluble proteins, in addition to the high frequency of auxotrophic and asporogenous mutations found amongst survivors.
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Affiliation(s)
- K Warriner
- Division of Food Sciences, School of Biological Sciences, University of Nottingham, Loughborough, UK
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