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This research introduces a fractional high-order sliding mode control (FHOSMC) method that utilises an inverse integral fractional order, 0 < β < 1 , as the high order on the FHOSMC reaching law, exhibiting a novel contribution in the related field of study. The application of the proposed approach into a bioreactor system via diffeomorphism operations demonstrates a notable improvement in the management of the bioreactor dynamics versus classic controllers. The numerical findings highlight an improved precision in tracking reference signals and an enhanced plant stability compared to proportional–integral–derivative (PID) controller implementations within challenging disturbance scenarios. The FHOSMC effectively maintains the biomass concentration at desired levels, reducing the wear of the system as well as implementation expenses. Furthermore, the theoretical analysis of the convergence within time indicates substantial potential for further enhancements. Subsequent studies might focus on extending this control approach to bioreactor systems that integrate sensor technologies and the formulation of adaptive algorithms for real-time adjustments of β -type fractional-orders. [ABSTRACT FROM AUTHOR]

As photosynthetic microorganisms, cyanobacteria play a dominant part in numerous ecological systems owing to their ability to fix carbon and nitrogen and are therefore an essential part of primary production in both aquatic and terrestrial environments. The utility of nitrogen-fixing cyanobacteria in plant biotechnology opens up promising strategies for the conservation and sustainable use of rare, endangered plant species and bioactive cell cultures. Here, we discuss the complicated physiological aspects of biological nitrogen fixation in cyanobacteria and their symbiotic relationship with plants. This review focuses on recent advances in biotechnological tools such as CRISPR-Cas9, nanotechnology and multiomics-based approaches for enhancing plant regeneration systems to cultivate specialized metabolites. We also look at the methods in vitro preservation of plants and how to scale up a culture using bioreactor systems. The review ends by highlighting the promise of cyanobacteria-powered plant biotechnology as a renewable mechanism for rare species conservation and specialized metabolites production, providing an optimistic modal, formative future direction in plant biosynthesis.

The editorial discusses the advancements in cell therapy, focusing on diverse cell types, induction methods, and culture techniques that are driving the potential of cell-based therapies. Key topics include the use of 3D organoid cultures for liver diseases, refining CAR-T cell therapies for cancer treatment, and exploring the potential of CAR-macrophages for solid tumor treatment. The editorial highlights the importance of gene editing, bioprocessing technologies, and optimizing cell delivery methods for the successful translation of cell therapies into clinical practice. Despite challenges, interdisciplinary collaboration is key to developing personalized and effective cell-based treatments for various diseases. [Extracted from the article]

This research introduces a fractional high-order sliding mode control (FHOSMC) method that utilises an inverse integral fractional order, 0<β<1, as the high order on the FHOSMC reaching law, exhibiting a novel contribution in the related field of study. The application of the proposed approach into a bioreactor system via diffeomorphism operations demonstrates a notable improvement in the management of the bioreactor dynamics versus classic controllers. The numerical findings highlight an improved precision in tracking reference signals and an enhanced plant stability compared to proportional–integral–derivative (PID) controller implementations within challenging disturbance scenarios. The FHOSMC effectively maintains the biomass concentration at desired levels, reducing the wear of the system as well as implementation expenses. Furthermore, the theoretical analysis of the convergence within time indicates substantial potential for further enhancements. Subsequent studies might focus on extending this control approach to bioreactor systems that integrate sensor technologies and the formulation of adaptive algorithms for real-time adjustments of β-type fractional-orders.

Hemi-pyocyanin (HPC) is a heterocyclic nitrogenous compound with some reported potential medical effects. The current report aimed to investigate the potential use of organic industrial waste for the production of HPC via microbial fermentation. The novel antidiabetic activity of HPC was also accessed and reported in this work. A peanut oil processing by-product (groundnut cake) was screened as the best substrate for Pseudomonas aeruginosa TUN03 conversion to obtain high-yield HPC. This compound was further produced in a 14 L bioreactor system on a large scale (6 L per pilot) and reached higher productivity (35.1 μg/mL) in a shorter time course of cultivation (8 h) compared to fermentation on a small scale in flasks (19.5 μg/mL; 3 days of fermentation). On assessing its activity, HPC demonstrated potent inhibition against α-glucosidase, an antidiabetic enzyme, with a low IC50 value (0.572 mg/mL) and a maximum inhibition rate of 100%. In an in silico study, HPC was found to inhibit α-glucosidase with a good binding energy score (−9.0 kcal/mol) via interaction with amino acids Lys156, Leu313, and Arg315 at the active site, and three bonds (1 H-acceptor and 2 pi-H) were generated. The data from five Lipkin's rules and ADMET-based pharmacokinetics and pharmacology revealed that HPC possesses drug-like properties and good ADMET properties within the required allotted limitations. The data obtained in the current work highlighted the potential application of groundnut cakes for the eco-friendly and scaled-up production of HPC, a new anti-α-glucosidase agent that should be further investigated for type 2 diabetes management. [ABSTRACT FROM AUTHOR]

This review provides a summary of the most recent advancements in bioreactor systems, which have become more popular over the past few decades due to the outstanding qualities they offer for the creation of plant tissue and organ cultures in the laboratory as well as on a large scale. It provides a comprehensive discussion on the application of bioreactor systems in fruit cultivation as well as current research. This review presents a solution for researchers who are interested in the cultivation of diverse fruit species, as well as describes the methods that are used in the bioreactor system to propagate various fruit species. [ABSTRACT FROM AUTHOR]

Microalgae have been recognized as powerful phototrophic cell-factories whose applications range from biomass production for food and feed purposes to the production of high-value products and biofuels. Microalgae have been considered a source of functional ingredients, such as polyunsaturated fatty acids, polysaccharides, essential minerals, vitamins and bioactive peptides that can have positive effects on human and animal health. Besides having high nutritional value due to the high percentage of proteins in their composition, microalgae generate high-value products, such as pigments, polysaccharides, bio-hydrogen, and even bio-polyesters with plastic-like properties. Algal biomass that remains after product recovery can be used as forage, biofertilizer or feedstock for biogas production. This step in overall algal production is important from an economic point of view due to the reduction in production costs. This paper presents the detailed study of the biotechnologically most important microalgae strains, and the design principles of photobioreactors for their cultivation. In addition, the main existing and potential high-value products derivable from microalgae, as well as utilization of microalgae for phytoremediation and biogas production, were reviewed.

Plant tissue cultures have been widely used in both fundamental and applied types of research on various biological species, and the scientific interest to transfer that technology in industrial scale has been rapidly growing. The use of in vitro technology for commercial propagation of different plant species and the production of bioactive compounds from them has become profitable industry worldwide. In the past decades, the progress in plant tissue culture technology was directed towards the introduction of the liquid medium for cultivation under submerged conditions in different bioreactor types, and automation of the entire process. Some applications of modified bioreactor systems and their importance for the advancement of plant biotechnology in the fields of agriculture, medicine, and pharmacy are discussed in this review.

In the scope of a broader study about wine acetification, previous works concluded that using a single bioreactor hindered simultaneously reaching high productivities with high substrate consumption and the use of two serially arranged bioreactors (TSAB) could achieve such goal. Then, the aim of this work is the optimization, using Karush–Kuhn–Tucker (KKT) conditions, of this TSAB using polynomial models previously obtained. The ranges for the operational variables leading to either maximum and minimum mean rate of acetification of 0.11 ≤ (rA)global ≤ 0.27 g acetic acid·(100 mL·h)−1 and acetic acid production of 14.7 ≤ Pm ≤ 36.6 g acetic acid·h−1 were identified; the results show that simultaneously maximizing (rA)global and Pm is not possible so, depending on the specific objective, different operational ranges must be used. Additionally, it is possible to reach a productivity close to the maximum one (34.6 ≤ Pm ≤ 35.5 g acetic acid·h−1) with an almost complete substrate use [0.2% ≤ Eu2 ≤ 1.5% (v/v)]. Finally, comparing the performance of the bioreactors operating in series and in parallel revealed that the former choice resulted in greater production. [ABSTRACT FROM AUTHOR]

Biological nitrogen removal (BNR) technologies are the most effective approaches for the remediation of environmental nitrogen pollutants from wastewater treatment plants (WWTPs). Presently, research is going on to elucidate the structure and function of BNR microbial communities and optimizing BNR treatment systems to enhance nitrogen removal efficiency. The literature on BNR microbial communities and experimental datasets is not unified across various repositories, while a uniform resource for the collection, annotation, and structuring of these BNR datasets is still unavailable. Herein, we present the Biological Nitrogen Removal Database (BNRdb), an integrated resource containing various manually curated BNR-related data. At present, BNRdb contains 23,308 microbial strains, 46 gene families, 24 enzymes, 18 reactions, 301 BNR treatment datasets, 860 BNR-associated next-generation sequencing datasets, and 6 common BNR bioreactor systems. BNRdb provides a user-friendly interface enabling interactive data browsing. To our knowledge, BNRdb is the first BNR data resource that systematically integrates BNR data from archaeal, bacterial, and fungal communities. We believe that BNRdb will contribute to a better understanding of BNR process and nitrogen bioremediation research.

Microalgae have been recognized as powerful phototrophic cell-factories whose applications range from biomass production for food and feed purposes to the production of high-value products and biofuels. Microalgae have been considered a source of functional ingredients, such as polyunsaturated fatty acids, polysaccharides, essential minerals, vitamins and bioactive peptides that can have positive effects on human and animal health. Besides having high nutritional value due to the high percentage of proteins in their composition, microalgae generate high-value products, such as pigments, polysaccharides, bio-hydrogen, and even bio-polyesters with plastic-like properties. Algal biomass that remains after product recovery can be used as forage, biofertilizer or feedstock for biogas production. This step in overall algal production is important from an economic point of view due to the reduction in production costs. This paper presents the detailed study of the biotechnologically most important microalgae strains, and the design principles of photobioreactors for their cultivation. In addition, the main existing and potential high-value products derivable from microalgae, as well as utilization of microalgae for phytoremediation and biogas production, were reviewed. [ABSTRACT FROM AUTHOR]

Plant tissue cultures have been widely used in both fundamental and applied types of research on various biological species, and the scientific interest to transfer that technology in industrial scale has been rapidly growing. The use of in vitro technology for commercial propagation of different plant species and the production of bioactive compounds from them has become profitable industry worldwide. In the past decades, the progress in plant tissue culture technology was directed towards the introduction of the liquid medium for cultivation under submerged conditions in different bioreactor types, and automation of the entire process. Some applications of modified bioreactor systems and their importance for the advancement of plant biotechnology in the fields of agriculture, medicine, and pharmacy are discussed in this review. [ABSTRACT FROM AUTHOR]

In the scope of a broader study about wine acetification, previous works concluded that using a single bioreactor hindered simultaneously reaching high productivities with high substrate consumption and the use of two serially arranged bioreactors (TSAB) could achieve such goal. Then, the aim of this work is the optimization, using Karush–Kuhn–Tucker (KKT) conditions, of this TSAB using polynomial models previously obtained. The ranges for the operational variables leading to either maximum and minimum mean rate of acetification of 0.11 ≤ (rA)global ≤ 0.27 g acetic acid·(100 mL·h)−1 and acetic acid production of 14.7 ≤ Pm ≤ 36.6 g acetic acid·h−1 were identified; the results show that simultaneously maximizing (rA)global and Pm is not possible so, depending on the specific objective, different operational ranges must be used. Additionally, it is possible to reach a productivity close to the maximum one (34.6 ≤ Pm ≤ 35.5 g acetic acid·h−1) with an almost complete substrate use [0.2% ≤ Eu2 ≤ 1.5% (v/v)]. Finally, comparing the performance of the bioreactors operating in series and in parallel revealed that the former choice resulted in greater production.

The use of benchtop bioreactors (BRs) for the development of mammalian cell perfusion cultures is expensive and time consuming, given its complexity in equipment and operation. Scale‐down models, going from liter to milliliter scale, are needed to support the rapid determination of suitable operating conditions in terms of viable cell density (VCD), perfusion rate, and medium composition. In this study, we compare the performance of steady‐state perfusion cultures in orbitally shaken tube and BR systems for a given Chinese hamster ovary cell line. The developed scale‐down model relied on a daily workflow designed to keep the VCD constant at specific target values. This includes: cell count, removal of excessive cells (bleeding), spin down of remaining cells, harvest of cell‐free supernatant, and resuspension in fresh medium. Steady‐state cultures at different VCD values, medium exchange rates and working volumes were evaluated. Shake‐tube perfusion cultures allowed the prediction of cell‐specific growth, glucose consumption, ammonia, and monoclonal antibody production rates for much larger BRs, but not lactate (LAC) production rates. Although charge variant profiles remained comparable, different glycosylation patterns were obtained. The differences in LAC production and glycosylation probably resulted from the discontinuous medium exchange, the poor carbon dioxide removal, and the deficient pH control. Therefore, if requested by the specific process to be developed, product quality has to be fine‐tuned directly in the BR system. Altogether, the developed strategy provides a useful scale‐down model for the design and optimization of perfusion cultures with strong savings in time and media consumption. [ABSTRACT FROM AUTHOR]

Grape juice can be easily contaminated with ochratoxin A (OTA), one of the known mycotoxins with the greatest public health significance. Among the different approaches to decontaminate juice from this mycotoxin, microbiological methods proved efficient, inexpensive and safe, particularly the use of yeast or yeast products. To ascertain whether immobilisation of the yeast biomass would lead to successful decontamination, alginate beads encapsulating Candida intermedia yeast cells were used in our experiments to evaluate their OTA-biosorption efficacy. Magnetic calcium alginate beads were also prepared by adding magnetite in the formulation to allow fast removal from the aqueous solution with a magnet. Calcium alginate beads were added to commercial grape juice spiked with 20 μg/kg OTA and after 48 h of incubation a significant reduction (> 80%), of the total OTA content was achieved, while in the subsequent phases (72–120 h) OTA was slowly released into the grape juice by alginate beads. Biosorption properties of alginate-yeast beads were tested in a prototype bioreactor consisting in a glass chromatography column packed with beads, where juice amended with OTA was slowly flowed downstream. The adoption of an interconnected scaled-up bioreactor as an efficient and safe tool to remove traces of OTA from liquid matrices is discussed. [ABSTRACT FROM AUTHOR]

Vaccine manufacturing processes are designed to meet present and upcoming challenges associated with a growing vaccine market and to include multi-use facilities offering a broad portfolio and faster reaction times in case of pandemics and emerging diseases. The final products, from whole viruses to recombinant viral proteins, are very diverse, making standard process strategies hardly universally applicable. Numerous factors such as cell substrate, virus strain or expression system, medium, cultivation system, cultivation method, and scale need consideration. Reviewing options for efficient and economical production of human vaccines, this paper discusses basic factors relevant for viral antigen production in mammalian cells, avian cells and insect cells. In addition, bioreactor concepts, including static systems, single-use systems, stirred tanks and packed-beds are addressed. On this basis, methods towards process intensification, in particular operational strategies, the use of perfusion systems for high product yields, and steps to establish continuous processes are introduced. [ABSTRACT FROM PUBLISHER]

Stem cells are promising cell sources for many biomedical applications including cell therapy, regenerative medicine, and drug discovery. However, the commonly used static tissue culture vessels can only generate a low number of cells. To provide an adequate number of stem cells for clinical applications, a scalable process based on bioreactors is needed. Stem cells can be either cultured as free cells/aggregates in suspension or as adherent cells on the solid substrates. Based on the cell property, different bioreactor configurations are developed to better expand stem cells while maintaining their differentiation capacity. In this review, several major types of bioreactor systems and their applications in stem cell engineering are discussed. Continued advancements in bioprocess and bioreactor research and development are important to engineer stem cells for their use in biomedical applications. [ABSTRACT FROM AUTHOR]

Abstract: Serogroup B outer membrane vesicles (OMV) with iron regulated proteins (IRP) from Neisseria meningitidis constitute the antigen for the vaccine against the disease caused by this bacterium. Aiming to enhance final OMV concentration, seven batch experiments were carried out under four different conditions: (i) with original Catlin medium; (ii) with original Catlin medium and lactate and amino acids pulse at the 6th cultivation hour; (iii) with Catlin medium with double initial concentrations of lactate and amino acids and (iv) Catlin medium without glycerol and with double initial concentrations of lactate and amino acids. The cultivation experiments were carried out in a 7-L bioreactor under the following conditions: 36°C, 0.5atm, overlay air 1L/min, agitation: 250–850rpm, and O2 control at 10%, 20h. After lactate and amino acids exhaustion, cell growth reached stationary phase and a significant release increase of OMV was observed. According to the Luedeking & Piret model, OMV liberation is non-growth associated. Glycerol was not consumed during cultivation. The maximum OMV concentration value attained was 162mg/L with correspondent productivity of 8.1mg/(Lh) employing Catlin medium with double initial concentrations of lactate and amino acids. The obtained OMV satisfied constitution and protein pattern criteria and were suitable for vaccine production. [Copyright &y& Elsevier]

Despite the compelling clinical needs in enhancing bone regeneration and the potential offered by the field of tissue engineering, the adoption of cell-based bone graft substitutes in clinical practice is limited to date. In fact, no study has yet convincingly demonstrated reproducible clinical performance of tissue-engineered implants and at least equivalent cost-effectiveness compared to the current treatment standards. Here, we propose and discuss how tissue engineering strategies could be evolved towards more efficient solutions, depicting three different experimental paradigms: (i) bioreactor-based production; (ii) intraoperative manufacturing, and (iii) developmental engineering. The described approaches reflect the need to streamline graft manufacturing processes while maintaining the potency of osteoprogenitors and recapitulating the sequence of biological steps occurring during bone development, including vascularization. The need to combine the assessment of efficacy of the different strategies with the understanding of their mechanisms of action in the target regenerative processes is highlighted. This will be crucial to identify the necessary and sufficient set of signals that need to be delivered at the injury or defect site and should thus form the basis to define release criteria for reproducibly effective engineered bone graft substitutes. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: In this paper, experimental investigations of an adaptive RST control scheme for the regulation of the ethanol concentration in fed-batch cultures of S. cerevisiae is presented. Our main objective is to prove efficiency and robustness of this controller in experimental applications ranging from laboratory to industrial scales. The controller only requires one on-line measurement signal, making it easily implementable in an industrial environment. Disturbance rejection is ensured thanks to an on-line parameter adaptation procedure, which delivers as a side product an estimate of the growth rate that can be used for process monitoring purposes. The robustification of the controller is achieved in a simple way, using the observer polynomial. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study is to illustrate the low-pressure plasma modified cellulose acetate (CA) membranes can display a fractionation capability that can be of major importance for the operation of continuous enzymatic membrane reactors. For this purpose, low-frequency (LF) and/or radio-frequency (RF) excitations were applied to coat ethylenediamine (EDA) monomer to alter physico-chemical characteristics of surface as well as narrowing pore size of CA type common ultrafiltration membrane. Membrane characteristics were evaluated using various physical and chemical techniques including contact angle, Fourier Transform Infrared Spectroscopy with Horizontal Attenuated Total Reflection attachment and scanning electron microscopy. Membrane performance based on efficient monosaccharide removal was tested by using a diffusion cell. The contact angle results showed that the grafted amino groups caused great increase on the polar nature of the CA membranes studied. A complete and permanent hydrophilic modification of a CA was achieved by LF plasma treatment. From the fractionation point of view, 120W and 10min seemed to be a better plasma condition for membrane modification using LF plasma system. Very high retention (>94%) was obtained with the LF/PlzP-modified CA membrane for disaccharides, while the retention for monosaccharides was rather low (<73%) at the same reaction time. [Copyright &y& Elsevier]

Abstract: We use a mathematical model, based on the N-tanks-in-series approach, to evaluate the potential advantages that can be obtained in solid-state fermentation processes by operating packed-bed bioreactors as multi-layer beds. We explore classical operation, in which air is blown unidirectionally through a substrate bed that remains immobile, with two strategies that involve movement of the layers. The first strategy involves batch operation, in which the positions of the layers are changed at 1h intervals, in a cycling motion. The second strategy involves continuous plug-flow of the layers, with the regular addition of new layers at the air outlet and removal of spent layers at the air inlet. Under the conditions of the simulation, the rate of metabolic heat generation during the steady state of the continuous plug-flow process is only 60% of the peak value predicted for classical operation. As a result, the maximum bed temperature in the continuous plug-flow process is 4.5°C lower than that predicted for classical operation. We conclude that the operation of multi-layer packed beds in the continuous plug-flow mode can improve bioreactor performance significantly. [Copyright &y& Elsevier]

Abstract: A new expression system for Lactococcus lactis based on the salt inducible BusA promoter and the BusR repressor gene of L. lactis MG1363 was developed. To achieve salt induction, the expression of BusR was modulated by introducing mutations to its promoter sequence. An activity of 6.0μkatl−1 of the model enzyme Lactobacillus amylovorus α-amylase was achieved in the bioreactor cultivation. The major advantage of the current expression system is that no additions of inducing agents are needed into bioreactor cultivations. [Copyright &y& Elsevier]

Abstract: A steady state, one-dimensional model is developed to describe biodegradation of a volatile organic compound (VOC) in a gas–solid fluidized bioreactor. For comparison purposes, biodegradation in a packed bed bioreactor is also modelled. The models are used to predict outlet concentrations of a VOC substrate (ethanol) and the estimates are compared to experimental data. The fluidized bioreactor model includes properties of the bubbles such as rise velocity, bubble size and gas exchange rate with the emulsion phase surrounding the bubbles. The overall rate of biodegradation is modelled with the two limiting cases of zero and first order kinetics with respect to the substrate, which depend on whether the overall resistance is limited by microbial growth or mass transport. The models highlight how maximum elimination capacity and removal efficiency are influenced by bubble properties, residence time, maximum specific growth rate of the microorganisms, and microbial population. [Copyright &y& Elsevier]

Abstract: We report the application of response surface methodology (RSM) for optimization of the media composition for β-keratinase production by a feather degrading Bacillus subtilis strain RM-01 in solid-state fermentation using chicken-feather as substrate. The optimized culture conditions for 5.0g of chicken-feathers moistened with distilled water (1:1, w/v, adjusted to pH 8.0) supplemented with maltose (10%, w/w) and sodium nitrate (1.25%, w/w) as best co-carbon and co-nitrogen sources, respectively resulted in 5-fold increase of β-keratinase production post-72h of incubation at 50°C compared to β-keratinase production under un-optimized condition. The purified β-keratinase was a 20.1kDa molecular weight serine protease requiring Fe2+ for enzyme activity, showed restricted substrate specificity for β-keratin, and exhibited a significant stability and compatibility with surfactants, and most of the tested commercial laundry detergents, thus demonstrating its feasibility for inclusion in laundry detergents formulations. [Copyright &y& Elsevier]

Abstract: Wine vinegar is obtained in a biotechnological process one of the crucial steps in which is the biological oxidation of the starting wine. Such a step is usually performed in a semi-continuous operation mode where a preset fraction of the culture medium is unloaded from the fermenter as product and the remainder left in it as inoculum to facilitate expeditious fermentation of the wine subsequently added to replenish the amount withdrawn. The overall performance of the fermenter can vary markedly depending on the particular operating conditions, and so can the quality of the product and the economy of the process as a result. Identifying the most suitable operating conditions therefore poses a typical optimization problem named as dynamic optimization or open-loop optimal control, which is solved by determining the time profiles for the control variables of the system in order to optimize a given cost function. Such a function represents the goal to be achieved as regards the specific needs of the problem. In Part III of this series the previously proposed model in Parts I and II has been used for addressing the dynamic optimization of the acetic fermentation process in terms of various objective functions, with special emphasis on productivity. [Copyright &y& Elsevier]

Abstract: In part I of this series a mathematical model for acetic acid fermentation was reported. However, no kinetic model can be complete until its equation parameters are estimated. This inevitably entails a practical identifiability analysis intended to ascertain whether the parameters can be estimated in an unambiguous manner based not only on the sensitivity of the model to them, but also on the amount and quality of available experimental data for this purpose. Also, estimating the model parameters entails optimizing a specific objective function subject to the model equations as major constraints and to additional, minor constraints on variables and parameters. This approach usually leads to the formulation of a non-linear programming problem involving differential and algebraic constraints where the decision variables constitute the parameter set to be estimated. In the scope of modelling biotechnological processes, this problem is not usually dealt with in a proper way. This second paper reviews available models for practical identifiability assessment and parameter estimation with a view to their prospective application to the proposed model and its validation. [Copyright &y& Elsevier]

Abstract: Vinegar is a food product of increasing significance by virtue of its widely variable origin and uses (particularly as a condiment or food preservative). The gastronomic value of vinegar has been appreciated for thousands of years. The growing social and economic significance of these products has fostered research into the most salient aspects of their production processes. The widespread use of submerged cultures in such processes has aroused an obvious interest in their modelling with a view to facilitating their design, control and optimization. Also, the availability of increasingly powerful utility and dedicated software tools has enabled a much rigorous approach to devising and application of more complex and accurate models for these purposes. This paper (Part I) reviews previous attempts at modelling acetic acid fermentation and proposes a new mathematical model for the process based on extensive experimental testing. The model introduces new equations and considers cell lysis during the process. Part II is devoted to study the key subject of parameter estimation and finally Part III deals with the optimization task. Though the wine vinegar process is being considered, many of the studied issues could be applied to other fermentations. [Copyright &y& Elsevier]

Abstract: We developed an easy-to-use, small-scale circulation-type bioreactor system that enables the simultaneous evaluation of many specimens. Medium flow was generated by a magnetic stirrer in this system. Primary rat hepatocytes formed a monolayer, and there were no morphological differences between cells in circulation and stationary cultures. The mitochondrial activity of hepatocytes in the circulation culture was 23% lower than that in the stationary culture after 2 days of culture. On the other hand, albumin production activity in the circulation culture after 2 days of culture was 1.4 times higher than that in the stationary culture. Albumin production activity per cell in the circulation culture was 1.9 times higher than that in the stationary culture after 2 days of culture. In addition, lidocaine metabolism rate per cell in the circulation culture was 1.3 times higher than that in the stationary culture. The lidocaine clearance of the circulation culture in our circulation-type bioreactor was 1.3 times higher than that of the stationary culture. It was shown that this bioreactor is suitable for the expression of the liver-specific functions of primary rat hepatocytes. Therefore, we can expect that this circulation-type bioreactor system will be a practical drug metabolism simulator. [Copyright &y& Elsevier]

Abstract: In this work, the synthesis of ricinoleic acid estolides, also named polyricinoleic acid (PR), in two different solvent-free reaction systems, catalysed by immobilised Candida rugosa lipase is described. First, the esterification was performed in an open air jacketed batch reactor and the influence of amount of enzyme, temperature and initial water content was tested. The best results were obtained when 5g of soaked immobilised derivative was used as biocatalyst, and the reaction was carried out at 40°C. It was observed that environmental relative humidity plays an important role in the enzymatic synthesis of ricinoleic acid estolides and, given that this parameter takes on a wide range of values depending on the season, it is considered the main cause of the poor reproducibility achieved in the open air reactor. To solve this problem, the ricinoleic acid estolides were synthesised under controlled atmosphere in a vacuum reactor with dry air intake. The optimum drying time of 7h was selected. In these conditions, PR with an acid value of 57.5mgKOH/g was synthesised in 48h of reaction and the results were entirely reproducible. [Copyright &y& Elsevier]

Biological nitrogen removal (BNR) technologies are the most effective approaches for the remediation of environmental nitrogen pollutants from wastewater treatment plants (WWTPs). Presently, research is going on to elucidate the structure and function of BNR microbial communities and optimizing BNR treatment systems to enhance nitrogen removal efficiency. The literature on BNR microbial communities and experimental datasets is not unified across various repositories, while a uniform resource for the collection, annotation, and structuring of these BNR datasets is still unavailable. Herein, we present the Biological Nitrogen Removal Database (BNRdb), an integrated resource containing various manually curated BNR-related data. At present, BNRdb contains 23,308 microbial strains, 46 gene families, 24 enzymes, 18 reactions, 301 BNR treatment datasets, 860 BNR-associated next-generation sequencing datasets, and 6 common BNR bioreactor systems. BNRdb provides a user-friendly interface enabling interactive data browsing. To our knowledge, BNRdb is the first BNR data resource that systematically integrates BNR data from archaeal, bacterial, and fungal communities. We believe that BNRdb will contribute to a better understanding of BNR process and nitrogen bioremediation research. [ABSTRACT FROM AUTHOR]

Modelling techniques allow certain processes to be characterized and optimized without the need for experimentation. One of the crucial steps in vinegar production is the biotransformation of ethanol into acetic acid by acetic bacteria. This step has been extensively studied by using two predictive models: first-principles models and black-box models. The fact that first-principles models are less accurate than black-box models under extreme bacterial growth conditions suggests that the kinetic equations used by the former, and hence their goodness of fit, can be further improved. By contrast, black-box models predict acetic acid production accurately enough under virtually any operating conditions. In this work, we trained black-box models based on Artificial Neural Networks (ANNs) of the multilayer perceptron (MLP) type and containing a single hidden layer to model acetification. The small number of data typically available for a bioprocess makes it rather difficult to identify the most suitable type of ANN architecture in terms of indices such as the mean square error (MSE). This places ANN methodology at a disadvantage against alternative techniques and, especially, polynomial modelling. [ABSTRACT FROM AUTHOR]