DOCSLIB.ORG

Electrical Impedance for Bacterial Metabolic Activity Screening-Evaluation of Single and Mixed Bacterial Consortia for Wastewater Biodegradation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Electrical Impedance for Bacterial Metabolic Activity Screening-Evaluation of Single and Mixed Bacterial Consortia for Wastewater Biodegradation International Food Research Journal 17: 591-599 (2010) Electrical impedance for bacterial metabolic activity screening-evaluation of single and mixed bacterial consortia for wastewater biodegradation *Lasik, M. and Nowak, J. Poznań University of Life Sciences, Faculty of Food Science and Nutrition ul. Wojska Polskiego 31, 60-624 Poznan, Poland Abstract: The use of an electrical impedance measurement method for selection of bacteria with high metabolic activity, specific for treatment of high loaded potato industry wastewaters was investigated. The dynamic and effectiveness of wastewater biodegradation were evaluated in two ways: by the analysis of electrical impedance changes caused by bacterial metabolism during bioremediation process as well as by the reduction of chemical oxygen demand (COD). The course of impedance signals were described with Gompertz mathematical model and a parameter of maximal impedance changes rate (Imax), expressed as % of impedance changes h-1, was proposed for bacterial metabolic activity screening tests. A significantly higher (p<0.05) metabolic activity of bacteria occurring in the mixed cultures in comparison with single isolates coming from them was determined. A linear correlation (r=0.89), found between the wastewater COD reduction and the values of the maximal impedance changes rate (Imax) allowed the use of electrical impedance method and the proposed parameter for easier and quicker, in comparison with classic COD measurement, evaluation of the microbial wastewater treatment capability. Keywords: Electrical impedance, single and mixed bacteria populations, potato processing wastewater, biodegradation Introduction (Surucu, 1999). The microorganisms occurring in mixed cultures are characterized by higher biological Food industry produces one of the largest streams activity and smaller nutritive requirements in of industry wastewater. A high organic load, quite comparison with single isolates (Sakazawa et al., frequently campaign character (occurring temporarily 1981; Surucu, 1999; Lim et al., 2001). Except that, in large quantities) of the wastewater, cause that in the case of processes carried out by use of mixed despite many solutions there is still an urgent cultures there were observed higher product yields, need to look for other new methods of rapid and higher growth rates and lower contamination dangers effective ways of utilization. Most study is focused in confrontation with processes of single cultures on the control of the process, modification of the (Yang et al., 2003; He et al., 2004). technologies etc. On the other hand, little is known A successful biodegradation process may require about the microflora operating in the processes. the use of multiple microorganism consortium with Microorganisms employed in the wastewater complementary metabolic capabilities. It can bring utilization include bacteria mainly from the genus numerous potential benefits, including the ability Bacillus. They are used most commonly in systems of to degradation of specific, toxic compounds and mixed populations (Sonnleitner and Fiechter, 1983; establishing catabolic pathways that have not been Surucu, 1999; Lapara et al., 2001; Lim et al., 2001; occurred by single cultures (Sakazawa, et al., 1981; Cibis et al., 2002; Krzywonos et al., 2008). Mixed Shimao et al., 1984; Ramos et al., 1996; Oh and cultures taking part in wastewater biodegradation are Bartha, 1997; Park et al., 1999; Gilbert et al., 2003). formed generally in a natural way, in the result of The objective of the presented study was to select their adaptation to environmental conditions as well bacteria isolates characterized by high metabolic as microbial synergistic and antagonistic interactions activity and capability for biodegradation and Corresponding author. Email: lasik@up.poznan.pl © All Rights Reserved Tel: +48 61 848 72 88; Fax: +48 61 848 73 14 592 Lasik, M. and Nowak, J. afterwards to develop from them a mixed culture wastes derived from the fruit and vegetable industry specific for the type of the treated wastewater. The (Lammas Resources Ltd., Corby, Northamptonshire, selection of the isolates, characterized by high the United Kingdom) and Mixed Culture C2 metabolic activity, was performed by employing (Bacillus laterosporus, Bacillus circulans, Bacillus the electrical impedance measurement method. fillocolonicus, Bacillus acidocaldarius, Bacillus The principle of the impedimetric technique is the stearothermophilus, Bacillus licheniformis) utilized measure of the electrical impedance changes caused for the process of hot potato slops biodegradation by the metabolic processes of microorganisms in the (Department of Bioprocess Engineering, Wroclaw culture medium. Molecules of high molecular weight University of Economics, Poland). The individual present in the medium (e.g. proteins, carbohydrates isolates obtained from the two mixed cultures were and fats) are degraded during biochemical processes identified by the Bergey key, API tests and the PCR of microorganisms to ionized metabolic products. method (unpublished data). Smaller, charged molecules result in the increase of All the microorganisms, mixed cultures and electric current conductivity and, consequently lead to single isolates coming from them were previously the decrease in the electrical impedance of the culture adapted to both types of wastewater, separately. environment (Noble, 1999; Gomez et al., 2002; The acclimatization was carried out by regularly Yunus et al., 2002). Primarily, this method is used passaging (every 3 days) on wastewater media by for rapid detection or quality and quantity analyses of shake culturing (130 rpm) at 55ºC (thermophilic microorganisms, especially in the quality control of conditions). food, pharmaceutical and cosmetic articles (Wawerla The inoculum was prepared using a nutritional et al., 1999). However, attempts were made to employ broth (BTL, Poland) as a growth medium. The impedance measurements for characterization of culture was carried out for 24 h in shaking conditions metabolic activities of microorganisms. Curda and (130 rpm) at the temperature of 55 °C. The inoculum Plockova (1995) investigated inhibiting properties used for the inoculation constituted 10% (v/v) of the of honey and its influence on the metabolic activities treated medium. of lactic acid bacteria, while Paquet et al. (2000) applied the measurement of electrical impedance to Evaluation of the metabolic activity of bacteria assess the activity of starter cultures in the process of The metabolic activity was performed by the cheese production. method of electrical impedance changes measurement In this study, the electrical impedance method is by using the Automatic Analyzer of Microorganisms proposed for selection of microorganisms consortia Growth BacTrac 4100 (Sy-Lab, Austria). Special with high metabolic activity for biological wastewater 10 ml measuring test tubes (Sy-Lab), equipped in utilization. The specific mixed bacteria cultures were 4 electrodes were used in the experiment. The test developed for the biodegradation of high loaded tubes were filled with 9 ml of wastewater, sterilized wastewater from a potato processing plant. at 121°C for 15 min and then inoculated with 1 ml inoculum of the tested bacteria population. As the Materials and Methods impedance changes strictly depend on the number of microorganisms in the sample, the inoculum was Wastewater diluted to the range from 3⋅103 to 4⋅103 cfu ml-1 and Two types of wastewater obtained from potato the number of viable bacteria cells in the inoculum processing plant (Wielkopolskie Przedsiebiorstwo was determined employing the classical plate method Przemysłu Ziemniaczanego, Lubon, Poland) were by using Plate Count Agar (Merck). The measuring used in the performed investigations: first, wastewater test tubes were incubated in the thermostat of the manufactured in the process of protein recovery from Automatic Analyzer of Microorganisms Growth potato juices by means of acid-thermal coagulation BacTrac 4100 for 24 h at 55°C. Changes in the – named hot wastewater, and second, wastewater electrical impedance of the treated wastewater, created during the process of starch production – caused by metabolic processes of bacteria, were named starch wastewater (Table 1). calculated in relation to the initial value according to the following formula: Microorganisms Two thermophilic Bacillus mixed cultures were used in the performed investigations: Mixed Culture C1 (Bacillus coagulans, Bacillus licheniformis, Bacillus laterosporus, Bacillus cereus) isolated from International Food Research Journal 17: 591-599 Electrical impedance for bacterial metabolic activity screening - evaluation of single and mixed bacterial consortia for wastewater593 Table 1. Chemical composition of potato starch wastewaters Concentration Parameters Unit Hot wastewater Starch wastewater Temperature ºC 80-85 10-20 pH - 5.3 ± 0.2 5.6 ± 0.3 COD [gO2 l-1] 31 ± 5 21 ± 5 BOD [gO2 l-1] 18 ± 3 10 ± 3 Total organic carbon (TOC) [g l-1] 9.4 ± 2.8 5.4 ± 1.2 Total nitrogen [g l-1] 2.1 ± 0.3 1.2 ± 0.1 Total phosphate [g l-1] 0.4 ± 0.1 0.2 ± 0.1 (y − y ) curves (Figure 1). The proposed parameters constitute y = 0 i ⋅100% authors own modification of those elaborated by y0 Zwietering (1993) and describe the dynamic of y – changes in the electrical impedance of the wastewater microbial growth (Lasik, 2004; Nowak et al., 2005). y0 – value of the electrical impedance at the beginning of culturing. The process of wastewater biodegradation y – value
Load more
Loading...
Loading...
Loading...
Loading...
Loading...

4 pages remaining, click to load more.

Recommended publications
  • Sampling and Quantification of Biofilms in Food Processing And
    21 Sampling and quantifi cation of biofi lms in food processing and other environments D. E. Nivens, and B. M. Co, Purdue University, USA and M. J. Franklin, The Center for Biofi lm Engineering, USA Abstract: In the food industry, assessment of food contact surfaces is necessary to determine whether equipment is properly cleaned and/or sanitized and whether living problematic microorganisms are present. Existing quantitative detection technologies are limited by the inability to directly detect living cells in sporadically dispersed biofi lms on large surface areas. Thus, precise and accurate sampling strategies must be coupled with detection technology. This chapter discusses sampling methods and standard (e.g., plating and ATP-bioluminescence) and emerging (e.g., spectrometry, immunosensor, and nucleic acid-based) quantitative techniques to detect biofi lms on food contact surfaces with a survey of function, analytical performance, and limitations. Key words: biofi lm, sampling methods, spectrometry, immunosensors, nucleic acid-based. 21.1 Introduction Defi nitions of biofi lms vary but most investigators agree that biofi lms usually consist of four main components: (i) water, (ii) the living microbial population, (iii) the surface to which the cells are adhered, and (iv) the associated extracellular matrix, which can consist of secreted polymers (2, 17, 20, 107). These polymers, usually polysaccharides and/or protein, allow the cells to form three-dimensional structures but are not required for biofi lms to proliferate on a surface (79). Biofi
    [Show full text]
  • Electrochemical Impedance Spectroscopy
    Electrochemical impedance spectroscopy: An effective tool for a fast microbiological diagnosis # Nardo Ramírez1, Angel Regueiro2, Olimpia Arias3, Rolando Contreras1 1Dirección de Diagnóstico Microbiológico, Centro Nacional de Investigaciones Científicas, CNIC Ave. 25 esq. 158, Cubanacán, Playa, Ciudad de La Habana, Cuba FOCUS 2Centro de Bioingeniería, CEBIO 3Instituto de Ciencia y Tecnología de Materiales,Universidad de La Habana, UH E-mail: nardo.ramirez@cnic.edu.cu ABSTRACT Dielectric spectroscopy, also called electrochemical impedance spectroscopy, is traditionally used in monitoring corrosion and electro-deposition processes in the coating and characterization assessment of many kinds of sensors and semi-conductors. Its application in biotechnology for the characterization of cell cultures has, however, been notably expanded in the last decade. As a transductional principle, impedance has been applied in the field of microbiology as a means of detecting and quantifying pathogenic bacteria. This paper reviews the state-of-the-art of Impedance Microbiology, its progress and its applications for the detection of foodborne pathogenic bacteria, including the use of interdigitated microelectrodes, the development of chip-based impedance microbiology and the integration of impedance biosensors along with other techniques such as dielectrophoresis and electropermeabilization. Reference is made to basic components, definitions and principles of this technique, as well as to the explanation of the components and principles for cell culture
    [Show full text]
  • Efficient Separation and Sensitive Detection of Listeria
    University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 12-2010 Efficient Separation and Sensitive Detection of Listeria Monocytogenes Using Magnetic Nanoparticles, Microfluidics and Interdigitated Microelectrode Based Impedance Immunosensor Damira Ashimkhanovna Kanayeva University of Arkansas Follow this and additional works at: http://scholarworks.uark.edu/etd Part of the Microbiology Commons Recommended Citation Kanayeva, Damira Ashimkhanovna, "Efficient Separation and Sensitive Detection of Listeria Monocytogenes Using Magnetic Nanoparticles, Microfluidics and Interdigitated Microelectrode Based Impedance Immunosensor" (2010). Theses and Dissertations. 194. http://scholarworks.uark.edu/etd/194 This Dissertation is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact scholar@uark.edu, ccmiddle@uark.edu. EFFICIENT SEPARATION AND SENSITIVE DETECTION OF LISTERIA MONOCYTOGENES USING MAGNETIC NANOPARTICLES, MICROFLUIDICS AND INTERDIGITATED MICROELECTRODE BASED IMPEDANCE IMMUNOSENSOR EFFICIENT SEPARATION AND SENSITIVE DETECTION OF LISTERIA MONOCYTOGENES USING MAGNETIC NANOPARTICLES, MICROFLUIDICS AND INTERDIGITATED MICROELECTRODE BASED IMPEDANCE IMMUNOSENSOR A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Cell and Molecular Biology By Damira Ashimkhanovna Kanayeva Al-Farabi Kazakh National University
    [Show full text]
  • Unraveling Microbial Biofilms of Importance for Food Microbiology
    Microb Ecol (2014) 68:35–46 DOI 10.1007/s00248-013-0347-4 MINIREVIEWS Unraveling Microbial Biofilms of Importance for Food Microbiology Lizziane Kretli Winkelströter & Fernanda Barbosa dos Reis Teixeira & Eliane Pereira Silva & Virgínia Farias Alves & Elaine Cristina Pereira De Martinis Received: 15 August 2013 /Accepted: 6 December 2013 /Published online: 27 December 2013 # Springer Science+Business Media New York 2013 Abstract The presence of biofilms is a relevant risk factors in Introduction the food industry due to the potential contamination of food products with pathogenic and spoilage microorganisms. The It is known that bacteria are remarkably capable of adjusting majority of bacteria are able to adhere and to form biofilms, their needs for survival in environments. Among the microbial where they can persist and survive for days to weeks or even characteristics enabling these adaptations one of the most longer, depending on the microorganism and the environmen- important is the ability of the microorganism to form biofilms, tal conditions. The biological cycle of biofilms includes sev- since it facilitates adaptation to harsh environmental eral developmental phases such as: initial attachment, matu- conditions. ration, maintenance, and dispersal. Bacteria in biofilms are In the last decades a substantial effort has been put forth to generally well protected against environmental stress, conse- improve our understanding on microbial biofilms, defined as quently, extremely difficult to eradicate and detect in food complex and well-organized biological communities embed- industry. In the present manuscript, some techniques and ded in a self-produced extracellular polymeric matrix that can compounds used to control and to prevent the biofilm forma- develop into moist surfaces, either biotic or abiotic [102, 180].
    [Show full text]
  • Implications of Electrical Impedance-Based Microbiological Technology in Pork Meat Processing Industry for the Rapid Detection and Quantification of Salmonella Spp
    Journal of Food Science and Engineering 7 (2017) 1-16 doi: 10.17265/2159-5828/2017.01.001 D DAVID PUBLISHING Implications of Electrical Impedance-Based Microbiological Technology in Pork Meat Processing Industry for the Rapid Detection and Quantification of Salmonella Spp. Cristina Pablos, Javier Marugán, Sandra Cristóbal and Rafael van Grieken Department of Chemical and Environmental Technology, University Rey Juan Carlos, C/Tulipán s/n, Móstoles (Madrid) 28933, Spain Abstract: The absence of efficient tools for preventing bacterial contamination in the meat processing industry as well as for detecting Salmonella positive samples in real time is a matter of concern. Impedance technology has proved its effectiveness as a bacterial quantification tool for research purposes instead of laborious standard plate count, and as a detection tool to substitute tedious current horizontal method ISO 6579:2002. Calibration curves were carried out for S. enteritidis and S. typhimurium in raw pork matrix (R2 > 0.90). Calibrations of mixtures of both strains at different ratio were prepared, showing a high efficiency to differentiate bacterial metabolism. Impediometry was also validated against standard plate count in raw pork samples treated by UV-C illumination to inactivate Salmonella. Even, damaged but still viable bacteria were recorded. Detection of Salmonella by impediometry led to a decrease in false positives, obtaining results within 30 h compared to 72 h in case of conventional method. Key words: Impediometry, S. enteritidis, S. typhimurium, quantification, detection, pork meat. 1. Introduction Over the past decade, regulations [4, 5] have laid down acceptable microbiological criteria for The high number of outbreaks of food- and meat-based products, requiring the absence of water-borne diseases caused by pathogenic bacteria Salmonella per 25 g of meat.
    [Show full text]
  • Methods of Rapid Microbiological Assay and Their Application to Pharmaceutical and Medical Device Fabrication
    Biocontrol Science, 2016, Vol. 21, No. 4, 193－201 Review Methods of Rapid Microbiological Assay and Their Application to Pharmaceutical and Medical Device Fabrication HIDEHARU SHINTANI Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo, Tokyo 112-8551, Japan Received 29 October, 2014/Accepted 26 January, 2016 There are several rapid microbiological methods becoming available that have useful applica- tions in pharmaceutical and medical devices. They are ATP bioluminescence, fluorescent labeling, electrical resistance, and nucleic acid probes. In choosing to employ rapid methods, the micro- biologist should examine their prospective performances against the specific requirements for that sector. Some methods may require expensive equipment and offer full automation, and others represent only a small investment. The regulatory view of these methods is changing and they still officially have not been approved in medical and pharmaceutical area, but it will still be up to the microbiologist to demonstrate that the method chosen is fit for the purpose intended. Key words ： Rapid microbiological methods / Bioburden / Pharmaceuticals / Medical devices. INTRODUCTION screening） and for microbiological quality assurance （MQA）. In the latter instance, the inevitable time delay Traditional microbiological methods of detection, enu- associated with incubation often determines that MQA meration, and identification using mostly culture meth- data are only of retrospective value. Pharmaceutical and ods are so often time-consuming and labor-intensive. medical device production can no longer accommodate These practical considerations often limit the extent to this delay（ Zuluaga et al., 2009; Akselband et al., 2005; which microbiological tests are routinely applied both at Dexter et al., 2003）. Considerable benefit would there- the formulation development stage（ i.e., preservative fore be gained from the introduction of suitable, more rapid methods of microbiological analysis to the phar- maceutical and medical device sector.
    [Show full text]
  • Bacterial Sensors and Controllers Based on Organic Bioelectronics
    From the Department of Neuroscience Karolinska Institutet, Stockholm, Sweden BACTERIAL SENSORS AND CONTROLLERS BASED ON ORGANIC BIOELECTRONICS Karen Butina Stockholm 2021 All previously published papers were reproduced with permission from the publisher. Published by Karolinska Institutet. Printed by Universitetsservice US-AB, 2021 © Karen Butina, 2021 ISBN 978-91-8016-049-0 Cover illustration: Delvin Flisek Bacterial sensors and controllers based on organic bioelectronics THESIS FOR DOCTORAL DEGREE (Ph.D.) By Karen Butina The thesis will be defended in public at Karolinska Institutet, Stockholm, 5th of February 2021 at 9:00 am. Principal Supervisor: Opponent: Prof. Agneta Richter-Dahlfors Tatsuro Goda, PhD Karolinska Institutet Toyo University AIMES Department of Biomedical Engineering Department of Neuroscience Examination Board: Co-supervisors: Prof. Staffan Svärd Prof. K. Peter R. Nilsson Uppsala University Linköping University Department of Cell and Molecular Biology Department of Physics, Chemistry and Biology Madeleine Ramstedt, PhD Umeå University Susanne Löffler, PhD Department of Chemistry Karolinska Institutet AIMES Prof. Fredrik Almqvist Department of Neuroscience Umeå University Department of Chemistry To Johan and Johan. Your friendship made it worthwhile. POPULAR SCIENCE SUMMARY OF THE THESIS Bacteria are forming a big part of our body and are necessary for our well-being since they help us digest certain foods and keep our skin healthy. However, they can also be very harmful and make us sick. This can happen if we get some “bad” bacteria, but also if the good ones enter places they should not – for example our bloodstream. If we get an infection, our doctor prescribes antibiotics to kill the bacteria – but they do not always work.
    [Show full text]
  • The Use of Monoclonal and Polyclonal Antibodies to Identify Escherichia Coli " (1986)
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1986 The seu of monoclonal and polyclonal antibodies to identify Escherichia coli Charles William Kaspar Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Microbiology Commons Recommended Citation Kaspar, Charles William, "The use of monoclonal and polyclonal antibodies to identify Escherichia coli " (1986). Retrospective Theses and Dissertations. 9752. https://lib.dr.iastate.edu/rtd/9752 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact digirep@iastate.edu. INFORMATION TO USERS The most advanced technology has been used to photo­ graph and reproduce this manuscript from the microfilm master. UMI films the original text directly from the copy submitted. Thus, some dissertation copies are in typewriter face, while others may be from a computer printer. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyrighted material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are re­ produced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each oversize page is available as one exposure on a standard 35 mm slide or as a 17" x 23" black and white photographic print for an additional charge.
    [Show full text]
  • The Effect of Temperature and Water Activity on Microbial Growth Rate and Food Spoilage
    THE EFFECT OF TEMPERATURE AND WATER ACTIVITY ON MICROBIAL GROWTH RATE AND FOOD SPOILAGE. Robert Edward Chandler, B.Sc.(Hons.), Being a thesis in fulfilment of the requirements for the degree of Doctor of Philosophy (Microbiology), at the University of Tasmania. University of Tasmania, Hobart, Tasmania, Australia, January,H988... 7),24.0 Cksc), b coN6LER_ VCVA THE UNIVERSITY OF TASMANIA LiBRARY DECLARATION. This thesis contains no material which has been accepted for the award of any other degree or diploma in any University, and to the best of my knowledge contains no copy or paraphrase of material previously published or written by any other person, except where due reference is made in the text of this thesis. Robert Edward Chandler, University of Tasmania, Hobart, Tasmania, Australia, January, 1988. iii ABSTRACT. The Square Root Model [/r = b(T - T o )] was used to describe the temperature dependence of bacterial growth rate under conditions where temperature was the only limiting factor. It was validated for predicting the growth of the bacteria responsible for the spoilage of pasteurised, homogenised milk and for the in situ spoilage of the milk, over the storage range 0 to I5 ° C. A temperature function integrator, incorporating the Square Root Model and a T value of 263K was successfully used to monitor the o temperature history of pasteurised, homogenised milk over a range of storage temperatures and to display the cumulated storage history at an arbitrary reference temperature (4 ° C). The spoilage rate of pasteurised homogenised milk, with respect to temperature, was described accurately by a Square Root Equation, possessing a T value similar to that of the psychrotrophic o pseudomonads responsible for the spoilage of the milk.
    [Show full text]
  • Detection of Aerobic Bacterial Endospores: from Air Sampling, Sterilization Validation to Astrobiology
    DETECTION OF AEROBIC BACTERIAL ENDOSPORES: FROM AIR SAMPLING, STERILIZATION VALIDATION TO ASTROBIOLOGY Thesis by Pun To (Douglas) Yung In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 2008 (Defended May 9, 2008) ii © 2008 Pun To (Douglas) Yung All Rights Reserved iii Acknowledgment I would like to express my deepest gratitude to my thesis adviser, Dr. Adrian Ponce, for his guidance and support. It is due to his scholastic guidance and encouragement that ultimately made this work possible. I appreciate the time and attention of my committee members: Professor Morteza Gharib, Professor Scott Fraser, and Professor Changhuei Yang. Given their busy schedules, it has been kind of them to play a role in my course of study. I owe my gratitude to all members of the Ponce Group who have made this dissertation possible, and because of them my graduate experience has been one that I will cherish forever. Elizabeth Lester has kindly introduced me to techniques in microbiology. Alan Fung has taught me principles in mechanical engineering and instrument design. I have enjoyed working with Elizabeth Lester, Alan Fung, Morgan Cable, Hannah Shafaat and Wanwan Yang. I would like express thanks to my summer undergraduate mentees, Wilson Sung, Christine Tarleton, and William Fan, who have contributed important pieces to my thesis work. I would like to acknowledge the other individuals who have contributed to the completion of this thesis: Dr. James Kirby, Dr. Xenia Amashukeli, Dr. Christine Pelletier, Raymond Lam, Dr. Michael Kempf, Michael Lee, Dr. Fei Chen, Dr.
    [Show full text]
  • Biosensors for the Detection of Food Pathogens
    Foods 2014, 3, 511-526; doi:10.3390/foods3030511 OPEN ACCESS foods ISSN 2304-8158 www.mdpi.com/journal/foods Review Biosensors for the Detection of Food Pathogens Palmiro Poltronieri 1,*, Valeria Mezzolla 1, Elisabetta Primiceri 2,3 and Giuseppe Maruccio 2,3 1 Institute of Sciences of Food Productions, National Research Council, ISPA-CNR, Via Lecce-Monteroni, 73100 Lecce, Italy; E-Mail: valeria.mezzolla@gmail.com 2 NNL, Institute of Nanoscience-CNR, Via per Arnesano, I-73100 Lecce, Italy; E-Mails: elisabetta.primiceri@unisalento.it (E.P.); giuseppe.maruccio@unisalento.it (G.M.) 3 Department of Mathematics and Physics “Ennio De Giorgi”, University of Salento, Via per Arnesano, I-73100 Lecce, Italy * Author to whom correspondence should be addressed; E-Mail: palmiro.poltronieri@ispa.cnr.it; Tel.: +39-0832-422-609; Fax: +39-0832-422-620. Received: 2 May 2014; in revised form: 18 August 2014 / Accepted: 20 August 2014 / Published: 2 September 2014 Abstract: Food pathogens frequently cause foodborne diseases. There is a need to rapidly identify the source of the bacteria in order to contain their spread and epidemics. A pre-enrichment culture or a direct culture on agar plate are standard microbiological methods. In this review, we present an update on alternative molecular methods to nucleic acid-based detection for species identification. Biosensor-based methods rely on the recognition of antigen targets or receptors by antibodies, aptamers or high-affinity ligands. The captured antigens may be then directly or indirectly detected through an antibody or high-affinity and high-specificity recognition molecule. Various different detection methods are discussed, from label-free sensors and immunosensors to fluorescence-based ones.
    [Show full text]
  • Arthrospira Platensis As Natural Fermentation Booster for Milk and Soy Fermented Beverages
    foods Article Arthrospira platensis as Natural Fermentation Booster for Milk and Soy Fermented Beverages Francesco Martelli , Marcello Alinovi, Valentina Bernini, Monica Gatti * and Elena Bancalari Department of Food and Drug, University of Parma, 43124 Parma, Italy; francesco.martelli@studenti.unipr.it (F.M.); marcello.alinovi@studenti.unipr.it (M.A.); valentina.bernini@unipr.it (V.B.); elena.bancalari@unipr.it (E.B.) * Correspondence: monica.gatti@unipr.it Received: 30 January 2020; Accepted: 12 March 2020; Published: 18 March 2020 Abstract: Arthrospira platensis, commercially known as Spirulina, is a fresh-water cyanobacterium that has been gaining increasing attention in recent years due to its high biological and nutritional value. For this reason, it has been employed in several food applications, to obtain or enhance functional and technological properties of cheese, yogurt, bread, cookies or pasta. The aim of this work was to evaluate the potential boosting effect of two different concentrations (0.25% and 0.50% w/v) of A. platensis on the fermentation capability of several starter lactic acid bacteria (LAB) strains, 1 probiotic and 4 commercial mix culture. These strains were used to ferment three different substrates and their fermentation behaviors were evaluated by impedance analyses together with rheological and color measurements. In tryptic soy broth (TSB), the A. platensis boosting effect was significantly higher if compared to yeast extract for all the starter LAB strains except for Lb. casei, which was equally stimulated. Different results were found when the same LAB strains were cultivated in SSM. The most evident boosting effect was found for S. thermophilus and Lb.
    [Show full text]