Monitoring Of Fermentation Process Research Articles

SIRE-Technology. Part III. Glucose Monitoring During Fermentation of a Lignocellulosic Hydrolysate by Saccharomyces Cerevisiae Employing a Differential Amperometric Biosensor

A biosensor with an injectable recognition element (SIRE-biosensor) was used to measure the glucose concentration in undiluted samples from a fermentation of a hardwood hydrolysate. Glucose oxidase (1 mg/ml, 184.9 U/ml) was used as the recognition element in combination with an amperometric transducer. The results obtained with the SIRE-biosensor showed a good correlation to those obtained with an established analytical procedure (HPLC). The correlation coefficient and regression line between the two methods were r = 0.996 and y = 0.86 × −0.21. Thus, the results from the SIRE-biosensor were slightly lower than those obtained with HPLC, and the reasons herein are discussed. The SIRE-biosensor had a sampling frequency of 12 samples per hour, whereas the HPLC only allowed measurements of 1.2 samples per hour and required dilution of the samples. Additionally, the SIRE-biosensor measurements do not require any sample preparation, thus suggesting that the sensor can be used for in situ monitoring of fermentation processes.

Monitoring of fermentation processes producing lactic acid bacteria by mid-infrared spectroscopy

Fourier transform mid-infrared (FT-MIR) spectroscopy was used to determine the concentrations of substrate, major metabolites and lactic acid bacteria in fermentation processes. Partial least-squares regression gave the following standard errors of prediction (SEP): 3.4 g/l for lactose, 1.5 g/l for galactose. 0.9 g/l for lactic acid and 0.9 g/l for bacterial concentration. The principal vibrational assignments for the major compounds are provided. The spectra of filtered and non-filtered culture media containing lactic acid bacteria were not different with ordinary bacterial concentrations (up to 10 g/l) using a transmission cell.

Evaluation of detection and sample clean-up techniques for on- and off-line fermentation monitoring systems

Two different analytical systems for monitoring of fermentation processes were evaluated for the analysis of three carbohydrates: glucose, xylose and galactose. Samples taken during a controlled fermentation of the three sugars to ethanol were treated and analysed with both systems for the carbohydrate content. The first was an off-line system, based on manual sampling and clean-up, and column liquid chromatography (LC) in combination with refractive index (RI) detection and the other was an on-line set-up, based on microdialysis sampling, LC and an amperometric carbohydrate biosensor as the detection device. The manual clean-up consisted of centrifugation, filtration of the supernatant and dilution. First, the different clean-up procedures were compared, and the other parts of the system were kept constant, viz. the LC separation and the RI detector. Evaluation of the analysis response using the two clean-up procedures yielded in 12 or 13 cases higher values for the microdialysis probe than for the manual procedure. Two different statistical methods, one based on linear regression and another, a paired t-test, found the difference between the two clean-up procedures to be statistically significant. Detailed investigation of the manual clean-up procedure using analysis of variance (ANOVA) revealed that for identical samples treated by this method, a significant difference in-between the samples after treatment was found. Next, the two detection techniqueswere compared, using the manual clean-up procedure in combination with LC. It was found that the sugar content in 15 out of 16 samples was higher for the RI detector than for the biosensor and also in this case both the linear regression method and the paired t-test showed the difference to be statistically significant. Finally, studies on the performance of microdialysis probe membranes after use in a fermentation medium are presented.

A reagentless amperometric electrode based on carbon paste, chemically modified with D‐lactate dehydrogenase, NAD+, and mediator containing polymer for D‐lactic acid analysis. II. On‐line monitoring of fermentation process

The production of D-lactic acid by Lactobacillus delbrueckii (ATCC 9649) during fermentation was monitored on-line with a reagentless D-lactate dehydrogenase modified carbon paste electrode in a flow injection system integrated with a filtration sampling device. The time delay between sampling and detection was approximately 6 min. The use of an electropolymerized ortho-phenylenediamine membrane on the elctrode resulted in a very selective sensor response with acceptable stability and sensitivity. The D-lactate concentrations determined on-line agreed well with those determined by a standard method, suggesting that this sensor system is suitable for on-line monitoring of fermentation processes. (c) 1995 John Wiley & Sons, Inc.

A reagentless amperometric electrode based on carbon paste, chemically modified with D‐lactate dehydrogenase, NAD+, and mediator containing polymer for D‐lactic acid analysis. I. Construction, composition, and characterization

A reagentless carbon paste electrode was designed for D-lactic acid analysis in a flow injection system for the monitoring of the production of D-lactate in a batch fermentation. D-Lactate dehydrogenase, nicotinamide adenine dinucleotide (NAD(+)), a synthetic redox polymer containing covalently attached toluidine blue O as mediator, graphite powder, and paraffin oil were used for the construction of the modified carbon paste electrode. D-Lactate selectivity was indicated by insignificant responses from a variety of possible interfernces including L-lactate. The electrodes gave a linear response in the range between 0.05 and 5 mM D-lactate, with a detecting limit of 30 muM, allowing a sample throughput of 20 h(-1). Preliminary investigations were made by covering the electrode surface with electropolymerized membranes. Satisfactory stability was observed, indicated by a reproducibility of 3.3% relative standard deviation (RSD, n = 31), with a non-membrane-covered electrode for the analysis of D-lactate in fermentation broth. A long-term stability (230 broth samples) was proven, suggesting the electrodes to have a good potential for use in on-line monitoring of fermentation processes. (c) 1995 John Wiley & Sons, Inc.

Multirate state and parameter estimation in an antibiotic fermentation with delayed measurements

This article discusses issues related to estimation and monitoring of fermentation processes that exhibit endogenous metabolism and time-varying maintenance activity. Such culture-related activities hamper the use of traditional, software sensor-based algorithms, such as the extended kalman filter (EKF). In the approach presented here, the individual effects of the endogenous decay and the true maintenance processes have been lumped to represent a modified maintenance coefficient, m(c). Model equations that relate measurable process outputs, such as the carbon dioxide evolution rate (CER) and biomass, to the observable process parameters (such as net specific growth rate and the modified maintenance coefficient) are proposed. These model equations are used in an estimator that can formally accommodate delayed, infrequent measurements of the culture states (such as the biomass) as well as frequent, culture-related secondary measurements (such as the CER). The resulting multirate software sensor-based estimation strategy is used to monitor biomass profiles as well as profiles of critical fermentation parameters, such as the specific growth for a fed-batch fermentation of Streptomyces clavuligerus.

Application of pattern recognition to monitoring fermentations ofBacillus amyloliquefaciens

Pattern recognition techniques were applied to analytical data to distinguish abnormal from normal microbial fermentations usingBacillus amyloliquefaciens as a model system. Patterns of fermentation end products during growth ofB. amyloliquefaciens were obtained from HPLC analysis of broth samples. Data were also obtained from fermentations using other bacterial species, strains, and environmental conditions, and were compared with the model data set. The bacterial species cultured includedB. subtilus, B. licheniformis, andEscherichia coli. Environmental variables included acration and temperature. The chromatographic patterns were compared by using hierarchical cluster and principal component analysis to obtain a quantitative measure of their similarity and to establish the normal variability within a model data set. Statistical analysis of the data indicated that individual fermentations can be assigned to distinct clusters on the basis of their divergence from the model system. Altered environments and other species can be identified as outliers from the model set. These results show that pattern recognition analysis has direct applicability to monitoring fermentation processes.

Microbial biosensors for process and environmental control

For rapid and precise monitoring of the various factors involved in fermentation reactions and environment, it seems entirely sensible to employ the microorganisms themselves, which are highly sensitive to change in their environment. This review has touched upon some of the ways in which microbial sensors might be employed to monitor levels of fermentation substrates, reaction products, nutrients and antibiotics. This account has dealt almost entirely with those microbial sensors that are being investigated and developed in Japan for application to the monitoring of fermentation processes and environmental materials. Much work remains to be done. Sensors that work well under laboratory conditions do not always succeed when placed in industrial media, however, and basic research on sensors using microorganisms and new mutations with improved properties must be backed up by developmental modification and refinement. Despite many attractive properties, only few immobilized enzyme probes have yet been applied in commercial instruments. To date only a very limited number of enzyme-electrode based systems have been introduced. Nevertheless, these and other types of biosensor are indispensable for the efficient operation of numerous biotechnological processes.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Fermentation Process Monitoring through Measurement of Aerosol Release

AbstractFermentation involves many complex biological processes, some of which can be difficult to monitor. In this study, aerosol measurement was explored as an additional technique for monitoring a batch aerobic fermentation process using Escherichia coli strain W3110. Using this technique, a small aerosol extraction flow from the fermentor was continuously dried in‐line and analyzed with an aerosol size spectrometer and an aerosol photometer, used to measure the size‐integrated aerosol concentration. The results of the measurements demonstrated that the bacterial growth rate and the aerosol number concentration changed in a similar fashion: the effluent aerosol number concentration increased during the exponential growth phase and subsequently decreased after the bacterial cell concentration had reached a stable level. This aerosol concentration increased sharply approximately 1 h after initiation of growth. Thus, this increase in aerosol concentration suggests that the release of aerosols changes as a function of the microbial product formation activity. The products may change the rheological properties of the liquid, especially if surface‐active compounds are produced. The increase in aerosol concentration corresponds to a decrease in the values of the measured surface tension during the same time frame. Furthermore, the aerosol size spectrometer and the photometer showed similar time traces of the effluent aerosols. The size distributions of the solid residues from the fermentation broth remained relatively constant, while the concentrations changed with the phase of fermentation. As the photometer is inexpensive, it appears promising as a convenient instrument for monitoring fermentation processes.

On-line fermentation process monitoring of carbohydrates and ethanol using tangential-flow filtration and column liquid chromatography

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOn-line fermentation process monitoring of carbohydrates and ethanol using tangential-flow filtration and column liquid chromatographyTorbjoern. Buttler, Kristina A. J. Johansson, Lo G. O. Gorton, and Gyorgy A. Marko-VargaCite this: Anal. Chem. 1993, 65, 19, 2628–2636Publication Date (Print):October 1, 1993Publication History Published online1 May 2002Published inissue 1 October 1993https://doi.org/10.1021/ac00067a014RIGHTS & PERMISSIONSArticle Views241Altmetric-Citations52LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (3 MB) Get e-Alerts Get e-Alerts

Application of computer to monitoring and control of fermentation process: Microbial conversion of ML‐236B Na to pravastatin

An automatic feeding process for microbial hydroxylation of ML236B sodium salt (ML-236B Na; compactin) by Streptomyces carbophilus SANK 62585 was developed. The hydroxylated product, pravastatin sodium salt (pravastatin; trade name Mevalotin), is an inhibitor of 3-hydroxy-3-methyglutaryl-coenzyme A reductase (HMG-CoA reductase) used as cholesterol-lowering drug. The hydroxylation activity of S. carbophilus was induced by the addition of ML236B Na to culture broth but inhibited by high concentration of ML236B Na. In order to obtain high conversion yield, it was necessary to maintain optimum ML236B Na concentration throughout the fermentation by continuous feeding. For this purpose, we developed an on-line monitoring method, which mainly consisted of a cross-flow filtration module, high-performance liquid chromatography (HPLC) analyzer, feed pump, and microcomputer for regulation of ML236B Na concentration. An algorithm for control of ML236B Na feed rate based on feedback and feed-forward control where conversion rate after Deltat was estimated by using regression analysis of the five latest values of conversion rate. In a fed-batch culture employing this system, the concentration of ML236B Na was maintained at optimum level during the fermentation and the productivity of pravastatin was increased threefold over that obtained in manual control culture.

Performances of aseptic sampling devices for on‐line monitoring of fermentation processes

Two liquid sampling systems, which are set in the bioreactor and can be sterilized in place, are described. They are composed primarily of an inorganic membrane filter which is either stationary or is set in a rotating motion. These systems have been tested during three types of fermentation processes (ethanol, lactic acid, and polysaccharide productions). The rotating system gave better filtration performances than the stationary sampler which can be used only in alcoholic fermentation. The rotating sampler was coupled with a high-pressure liquid chromatograph for the on-line quantitation of the major compounds present in the filtrate. The results are in good agreement with those obtained from off-line analysis on samples taken manually.

On-line monitoring of fermentation processes by ultrafiltration and column liquid chromatography

An automated on-line monitoring system for low-molecular-weight compounds (e.g. sugars) during fermentation processes is described. The applicability of cross-flow ultrafiltration, coupled on-line with high-performance liquid chromatography, is evaluated. Various detection modes for the determination of the test compounds lactose, glucose and fructose) in a complex fermentation broth are compared. In addition, the influence of some system parameters on the performance of several ultrafiltration modules for the removal of cellular and macromolecular broth constituents is investigated. A method for the fully automated determination of sugars during anE. coli batch culture in a brain-heart infusion medium is presented. With the present system five analyses can be performed every hour, using only 35μl of sample, without significant deterioration of the ultrafiltration process. Contamination by external micro-organisms was not observed and good correlation with an off-line method was found.

Application of Fiber‐Optic Fluorescence Measurements to On‐Line pH Monitoring of a Pseudomonad Fermentation Process

AbstractThis article reports results on the application of fluorophore‐based pH sensing to the monitoring of fermentation processes. Emphasis is placed on identifying potential strengths and limitations. A custom‐built fluorometer, designed to provide broad‐band excitation (&lt;420 nm) was used to monitor the emission of a pH‐sensitive fluorophore (1, 4‐dihydroxyphthalonitrile) in solution at two wavelengths. The overall sensing system was characterized with respect to biocompatibility, response, and stability. The biocompatibility results revealed that the growth rate of Pseudomonas fluorescens (NRRL B‐15132) was decreased by the fluorophore at high concentrations (≥100 μM). Correlating the observed pH with the ratio of the two wavelengths (488 nm/434 nm) rendered the pH‐sensing system immune to factors such as fluorophore oxidation, aeration, and reactor agitation. A comparison of response times for fluorescence and Ingold pH measurements revealed fluorescence sensing to be slower. This was attributed to imperfect mixing and position differences between the two sensors in the fermentor. During the course of fermentation, on‐line ratiometric pH measurements for NRRL B‐15132 batch process were affected by changes in ionic strength and cell concentration. A pH difference of 0.66 was recorded (using an Ingold electrode as the standard) after 120 h of the fermentation. Recommendations for overcoming limitations were made.

On-line monitoring and control of fermentation processes by flow-injection analysis

On line flow-injection analysis (FIA) systems were developed for the real-time measurement and control of concentrations of small molecules (i.e. MW < 500) in fermentation media. An on-line tangential flow filtration device was developed to provide a particle-free sample stream to the analyzers. Analysis of fermentation supernatant is problematic because it is a complex and variable sample matrix. Using FIA techniques, in-line sample pretreatment strategies have been implemented to eliminate specific interferences. Two examples, demonstrating the use of on-line FIA for monitoring acetate and for controlling phosphate in E. coli fermentations, are discussed.

Rapid estimation of glucose and amylase in fermentation culture broth with test strips by reflectance photometry

The applicability of clinical multilayer test strips based on dry reagent chemistries for the quantitative analysis of fermentation media constituents was evaluated. For glucose and amylase determinations a significant correlation to conventional wet chemical methods was obtained. Bacterial biomass in the range of 0.5–5 g/l has no interfering effect. It is a rapid and cost-effective method for fermentation process monitoring and control.

On-line high-performance liquid chromatography for monitoring fermentation processes for penicillin production

The control and regulation of a fermentation process requires accurate and reliable on-line measurements of media components, often over long periods of time. As an alternative to wet chemical and enzymatic methods, high-performance liquid chromatography (h.p.l.c.) can be used. In addition to the product, penicillin V, important by-products and degradation products, as well as the precursor, phenoxyacetic acid, are determined. This makes it possible to control the precursor feed and to establish the optimal harvest time. Moreover, contamination can be detected at an early stage. Control of the precursor feed is desirable because the phenoxyacetic acid represents about 10% of the production costs and because higher concentrations could be toxic. The sterile sample flow is removed from the reactor by a microfiltration probe and drawn through the injection loop of an h.p.l.c. valve. Three analyses per hour can be done, and selected data from a computing integrator are fed to a process computer. The system works reliably for 300 h without requiring further calibration.

Quadrupole mass spectrometry in the monitoring and control of fermentations

The application of quadrupole mass Spectrometry to the monitoring of fermentation processes allows continuous and simultaneous non-invasive measurement of gases and volatile substrates, intermediates or products. Components are directly and continuously sampled through a silicone rubber membrane either from solution in the culture medium and/or in the influent or effluent gas streams. Gases measured include H 2, CH 4, O 2, CO 2, H 2S, N 2, N 2O and (as calibration standard) Ar: vapours include methanol, ethanol, propanol, acetone, n-butanol, acetic acid and butyric acid. This versatility of detection is enhanced by off-line determinations of non-volatiles after pH adjustment (e.g. total CO 2− 3 or NH + 4) or derivativization (e.g. some carboxylic or keto acids). Appropriate automation allows multicomponent analysis at many sampling points (i.e. simultaneously in many different fermentors). Applications are described for aerobic processes (antibiotic production, yeast fermentation, growth on methanol) and anaerobic processes (acetone-butanol fermentation, anaerobic digestion of farm and domestic wastes, and fermentation in the rumen). Future developments include exploitation of the high sensitivity, long-term stability and high specificity of mass spectrometric measurements to process control and optimization.

A Computer‐aided noninterfering on‐line technique for monitoring oxygen‐transfer characteristics during fermentation processes

The role of computers in the monitoring and control of fermentation processes has increased steadfastly. The ultimate utility of the machines will not depend on the availability of online sensors but also on the availability of techniques that combine direct measurements, leading towards estimates of variable closely related to the microbial process or its control. In this article, a methodology for on-line and noninterfering evaluation of the volumetric mass-transfer coefficient K(l)a is developed. A detailed presentation of the procedure, called "the static method," is given. Its feasibility is proved through implementation of the method on an antibiotic fermentation process. These experiments indicate that operator actions meant to modify the oxygen-transfer conditions can be checked on-line. The quantitative value of the static method is ascertained by comparing the experimental results with K(l)a estimates obtained with the "gassing-out" method. A sensitivity analysis was carried out, revealing the need for temperature and pressure corrections and showing that the precision of the oxygen analyzer determines the precision of the static method.

Online monitoring of fermentation processes

In biotechnology, few online measurements of biological variables are available. This fact hampers effective monitoring and control in the fermentation field. A novel approach to this is the use of a computer to combine outputs of online sensors for physical and chemical parameters to estimate directly otherwise unaccessible biological quantities like biomass. Here, a sensor configuration is presented for the online computation of the oxygen uptake rate. The equations that have to be implemented on the digital machine are derived and a case study on the fermentation of the antibiotic Gramicidine-S is performed and discussed. The experiments indicate that for a major part of the growth and fermentation period, the computer is suitable for the evaluation of the biomass based on oxygen uptake estimates. Consequently, the process can be monitored online.