Reactive extraction of muconic acid by hydrophobic phosphonium ionic liquids - Experimental, modelling and optimisation with Artificial Neural Networks.

Muconic acid is a six-carbon dicarboxylic acid with conjugated double bonds that finds extensive use in the food (additive), chemical (production of adipic acid, monomer for functional resins and bio-plastics), and pharmaceutical sectors. The biosynthesis of muconic acid has been the subject of recent industrial and scientific attention. However, because of its low concentration in aqueous solutions and high purity requirement, downstream separation presents a significant problem. Artificial Neural Networks and Differential Evolution were used to optimize process parameters for the recovery of muconic acid from aqueous streams in a system with n-heptane as an organic diluent and ionic liquids as extractants. The system using 120 g/L tri-hexyl-tetra-decyl-phosphonium decanoate dissolved in n-heptane, pH of the aqueous phase 3, 20 min contact time, and 45 °C temperature assured a muconic acid extraction efficiency of 99,24 %. Low stripping efficiency compared to extraction efficiency was observed for the optimum conditions on the extraction step (120 g/L ionic liquids dissolved in heptane). However, re-extraction efficiencies obtained for the recycled organic phase in three consecutive stages were close to the first extraction stage. The mechanism analysis proved that the analysed phosphonium ionic liquids (PILSs) extracts only undissociated molecules of muconic acid through H-bonding.

Can Combining Hyaluronic Acid and Physiotherapy in Knee Osteoarthritis Improve the Physicochemical Properties of Synovial Fluid?

Known as the degenerative disease of the knee with the highest prevalence, knee osteoarthritis (KOA) is characterized by a gradual destructive mechanism that, in severe cases, can provoke the need for total knee substitution. As the disease progresses, various enzymatic, immunological, and inflammatory processes abnormally degrade hyaluronic acid (HA), SF's main component, and affect the concentrations of specific proteins, with the final results seriously endangering synovial fluid (SF)'s rheological and tribological features and characteristics. No effective treatments have been found to stop the progression of KOA, but the injection of HA-based viscoelastic gels has been considered (alone or combined with physiotherapy (PT)) as an alternative to symptomatic therapies. In order to evaluate the effect of viscosupplementation and PT on the characteristics of SF, SF aspirated from groups treated for KOA (HA Kombihylan® and groups that received Kombihylan® and complex PT) was analyzed and compared from analytical, spectrophotometrical, and rheological perspectives. In the patients treated with PT, the SF extracted 6 weeks after viscosupplementation had a superior elastic modulus (G') and viscous moduli (G″), as well as a homogeneous distribution of proteins and polysaccharides. The viscosupplementation fluid improved the bioadhesive properties of the SF, and the use of the viscosupplementation fluid in conjunction with PT was found to be favorable for the distribution of macromolecules and phospholipids, contributing to the lubrication process and the treatment of OA-affected joints.

Cellular Stress Impact on Yeast Activity in Biotechnological Processes-A Short Overview.

The importance of Saccharomyces cerevisiae yeast cells is known worldwide, as they are the most used microorganisms in biotechnology for bioethanol and biofuel production. Also, they are analyzed and studied for their similar internal biochemical processes to human cells, for a better understanding of cell aging and response to cell stressors. The special ability of S. cerevisiae cells to develop in both aerobic and anaerobic conditions makes this microorganism a viable model to study the transformations and the way in which cellular metabolism is directed to face the stress conditions due to environmental changes. Thus, this review will emphasize the effects of oxidative, ethanol, and osmotic stress and also the physiological and genetic response of stress mitigation in yeast cells.

Selective pertraction of dicarboxylic acids from simulated Rhizopus oryzae fermentation broths.

Fumaric, malic and succinic acids have been selectively separated by facilitated pertraction with Amberlite LA-2, using n-heptane as liquid membrane. The feed phase consisted on viscous aqueous solution with similar mixture of carboxylic acids and viscosity as those of Rhizopus oryzae fermentation broth. Due to the differences between the acidities and molecule size of these acids, it is possible to selectively recover fumaric acid from the initial solution. The pH-gradient between the feed and stripping phases, as well as carrier concentration in the liquid membrane represent the main process parameters influencing the pertraction selectivity. Among them, Amberlite LA-2 concentration exhibits the most important control on the selectivity factor S, the maximum value of S being reached for carrier concentration of 30 g/l. The increase of feed phase viscosity amplified the magnitude of these influences on pertraction selectivity, due to the hindrance of acids diffusion towards the region where their reaction with Amberlite LA-2 occurs, effect more important for malic acid. Therefore, by modifying the viscosity from 1 to 24 cP, the maximum value of selectivity factor was increased from 12 to 18.8.

Variations in Biochemical Values under Stress in Children with SARS-CoV-2 Infection.

In the case of SARS-CoV-2 infection, children seem to be less affected than adults, but data regarding epidemiologic characteristics and biochemical values are poor and essentially based on limited case series. The aim of our study is to highlight the predictive value of some biochemical markers at hospitalization, for the correct classification of the patient in the form of disease. Methods: We performed an analytical retrospective study on 82 pediatric patients diagnosed with COVID-19 in the emergency department, with moderate or severe form of disease, and treated in our tertiary hospital. We analyzed the epidemiologic characteristics, symptomatology and biochemical values and compare the data according to the form of disease. Results: The mean age at admission was 4.5 years (median 1 year) and the masculine/feminine ratio was 1.5. Comparing the data between the two groups of patients (42 severe/40 moderate), we observed that the severe form presented with a lower pH at admission (p = 0.02), hyperglycemia (p = 0.01), increased values of transaminases (p = 0.01 and 0.02) and hypoproteinemia (p = 0.01). Also, the severe form was statistically significantly associated with comorbidities, acute respiratory distress, rising of the inflammatory markers during hospitalization. Hyperlactatemia (Lactate > 1.5 mmol/L) was significantly associated with the age under one year (p < 0.001). Mortality rate was 9.75% and the median age at death was 3 months. Univariate logistic regression model shows that the presence of anemia increased the probability of death 88 times, comorbidities 23.3 times and ketoacidosis 16.4 times. Conclusions: Metabolic acidosis, hyperlactatemia, hyperglycemia, modified hepatic values and hypoproteinemia are biochemical markers associated with the severe form of disease in SARS-CoV-2 infection in children. Presence of anemia, comorbidities and ketoacidosis are important risk factors for death of pediatric patients with SARS-CoV-2 infection.

Fractionation of dicarboxylic acids produced by Rhizopus oryzae using reactive extraction.

Fumaric, malic, and succinic acids have been selectively separated from their mixture obtained by Rhizopus oryzae fermentation using reactive extraction with Amberlite LA-2 dissolved in three solvents with different dielectric constants (n-heptane, n-butyl acetate, and dichloromethane). This technique allows recovering preferentially fumaric acid from the mixture, the raffinate containing only malic and succinic acids. The extractant concentration and organic phase polarity control the efficiency and selectivity of acids extraction. The increase of aqueous phase viscosity reduces the extraction yield for all studied acids, but exhibits a positively effect on separation selectivity. By using Amberlite LA-2 concentration equal to that stoichiometrically required for interfacial reaction with fumaric acid and mixing intensity which does not allow higher diffusion rates for larger molecules (malic and succinic acids), the maximum value of fumaric acid extraction rate exceeds 90%, while the selectivity factor value becomes 20. Regardless of the extraction system, the complete separation of fumaric acid from their mixture is possible by multi-stage extraction process, adjusting the extractant concentration in each stage. At higher values of aqueous phase viscosity, more extraction stages are required, while the increase of solvent polarity reduce the required number of stages for total recovery of fumaric acid.

Direct Extraction of Fumaric Acid from Rhizopus oryzae Suspensions-Interfacial Mass Transfer.

Experimental studies on the reactive extraction of fumaric acid with Amberlite LA-2 from Rhizopus oryzae suspensions using three solvents with different dielectric constants varying from 9.08 to 1.90 (dichloromethane, n-butyl acetate, and n-heptane, respectively) underlined the particular behavior of the extraction system in the presence of fungal biomass. The interfacial mass flow of the reaction product was found to be significantly affected by the biomass, due mainly to its adsorption onto the phase separation interface, this leading to the appearance of a physical barrier against the solute's transfer. However, the magnitude of the adsorption phenomenon was found to depend on Rhizopus oryzae's affinity for the solvent phase, which increased significantly from dichloromethane to n-heptane. The negative influence of the biomass on the interfacial mass transfer can be partially counteracted by adding 1-octanol into the organic phase, improving the solvent's ability to solve the fumaric acid-Amberlite LA-2 complex and simplifying the reactive extraction mechanism, effects that were found to be more important for low-polar solvents. Consequently, for the same mixing intensity, the maximum amplification factor was reached for n-heptane, its value being almost 5-6 times higher than that obtained for dichloromethane and over 2 times higher than that obtained with n-butyl acetate.

Neuroevolutive Algorithms Applied for Modeling Some Biochemical Separation Processes.

Combining artificial neural networks with evolutive/bioinspired approaches is a technique that can solve a variety of issues regarding the topology determination and training for neural networks or for process optimization. In this chapter, the main mechanisms used in neuroevolution are discussed and some biochemical separation examples are given to underline the efficiency of these tools. For the current case studies (reactive extraction of folic acid and pertraction of vitamin C), the bioinspired metaheuristic included in the neuroevolutive procedures is represented by Differential Evolution, an algorithm that has shown a great potential to solve a variety of problems from multiple domains.

Enhanced growth and ß-galactosidase production on Escherichia coli using oxygen vectors.

The addition of n-dodecane (between 1-3%) to the Escherichia coli fermentation broth in a mechanically agitated and aerated bioreactor revealed improved DO (dissolved oxygen) levels induced during fermentation which lead to an increase in biomass productivity and faster glucose consumption. The maximum values for enzyme activity (increased with 43% compared with the control) and k L a (the volumetric mass transfer coefficient) were obtained for the addition of 2% v/v n-dodecane in the bioreactor, due to the fact that oxygen limitation during the exponential growth phase of the bacterium can repress ß-galactosidase production. The oxygen vector addition increased the available dissolved oxygen and activated a redox-sensitive regulation and an elevated intracellular oxidative metabolism that lead to the enhancement in E. coli biomass accumulation and a more accurate protein folding of ß-galactosidase that would increase its activity. In addition to the experimental analysis, a complex model, developed using an improved version of Bacterial Foraging Algorithm and Artificial Neural Networks, was proposed, with a good average absolute value (6.2% in the training phase and 7.28% in the testing phase) between the process dynamic and the predictions generated by the model.

Mupirocin: applications and production.

Mupirocin is an antibiotic from monocarboxylic acid class used as antibacterial agent against methicillin-resistant Staphylococcus aureus (MRSA) and can be obtained as a mixture of four pseudomonic acids by Pseudomonas fluorescens biosynthesis. Nowadays improving antibiotics occupies an important place in the pharmaceutical industry as more and more resistant microorganisms are developing. Mupirocin is used to control the MRSA outbreaks, for infections of soft tissue or skin and for nasal decolonization. Due to its wide use without prescription, the microorganism's resistance to Mupirocin increased from up to 81%, thus becoming imperative its control or improvement. As the biotechnological production of Mupirocin has not been previously reviewed, in the present paper we summarize some consideration on the biochemical process for the production of pseudomonic acids (submerged fermentation and product recovery). Different strains of Pseudomonas, different culture medium and different conditions for the fermentation were analysed related to the antibiotics yield and the product recovery step is analysed in relation to the final purity. However, many challenges have to be overcome in order to obtain pseudomonic acid new versions with better properties related to antibacterial activity.

Fumaric acid: production and separation.

Fumaric acid is a valuable compound used in foods, beverages, detergents, animal feed, pharmaceuticals and miscellaneous industrial products. It is produced on a large scale by the petrochemical route but the current tendency is towards implementing "green production" and environmental friendly technologies like biotechnological production of fumaric acid using low-cost raw materials. In this context, numerous studies focus on improving the fermentation process not only by using renewable raw material and genetically modified microorganisms, but also by developing and applying different downstream techniques for easy recovery of fumaric acid from the fermented broth. This review presents the main methods for production and separation of fumaric acid, highlighting the advantages and disadvantages of these and the potential economic impact in industry.

Diffusional effects on anaerobic biodegradation of pyridine in a stationary basket bioreactor with immobilized Bacillus spp. cells.

The effects of external and internal diffusions of pyridine on its biodegradation rate in a bioreactor with a stationary basket bed of immobilized Bacillus spp. cells have been investigated for various biocatalyst diameters and thicknesses of the basket bed, considering the adapted Haldane kinetic model for substrate inhibition. Due to the very low values of pyridine mass flow inside the biocatalyst particles, the 'biological inactive region' appeared mainly near the particles' centre. This region is extended up to 38.5% from the overall volume of each studied size of the biocatalysts, increasing at higher biocatalyst size and basket bed width. Compared to the system containing free Bacillus spp. cells, the basket configuration of packed bed led to the reduction of biodegradation rate up to 82 times, similar to the mobile bed or column packed bed. The cumulated analysis of the influences of the studied factors allowed concluding that the optimum diameter of biocatalysts is 3 mm.

Nonconventional techniques for separation of biosynthetic amino acids.

Amino acids can be obtained by biosynthesis, by protein hydrolysis or by extraction from natural sources. The most efficient methods are the first two, but the separation of amino acids from fermentation broths or protein hydrolysates is rather difficult. Amino acids dissociate in aqueous solutions, forming characteristic ionic species depending on the solution pH-value. These properties make amino acids to be hydrophilic at any pH-value. This paper presents a review of the separation studies of some amino acids by nonconventional methods, namely individual or selective reactive extraction. Separation of some amino acids from their mixture obtained either by fermentation or protein hydrolysis by reactive extraction with different extractants indicated the possibility of the amino acids selective separation as a function of the pH-value of aqueous solution correlated with the acidic or basic character of each amino acid.

[Influences of internal diffusion on the lipids bio-degradation with immobilized Bacillus sp. cells in fixed bed of basket type]. / Implicatiile difuziei interne în biodegradarea lipidelor cu celulie imobilizate de Bacillus sp. dispuse in strat fix tip "basket".

AIM: This paper develops the previous studies on the transfer processes and biochemical reaction kinetics involved in the lipids biodegradation. MATERIAL AND METHODS: The experiments were carried out in 10 1(8 1 working volume) laboratory bioreactor with computer-controlled and recorded Parameters. The basket was placed centered around the stirrer and was filed with Bacillus sp. cells immobilized in alginate. The optimum impellers combination was found to be of two Rushton turbines, the superior one placed outside the basket and the other inside the basket at its inferior extremity. RESULTS: In the investigated case, the influences of the substrate internal diffusion on physical and biochemical processes have been quantified by means of the Biot number, Thiele modulus and reduction factor lambda. Compared to the system with free bacterial cells, biochemical processes rate is reduced inside the biocatalyst particle for about 150 - 200 times, this effect being more important than in the case of the bioreactor with mobile bed of immobilized yeast cells. CONCLUSIONS: The utilisation of immobilized biocatalysts offers many advantages, but allows the unfolding of the internal diffusion of substrate or product, with negative effect on the overall biochemical process evolution.

Succinic acid fermentation in a stationary-basket bioreactor with a packed bed of immobilized Actinobacillus succinogenes: 1. Influence of internal diffusion on substrate mass transfer and consumption rate.

This paper is dedicated to the study on external and internal mass transfers of glucose for succinic fermentation under substrate and product inhibitions using a bioreactor with a stationary basket bed of immobilized Actinobacillus succinogenes cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the Jerusalimsky kinetic model including both inhibitory effects, specific mathematical expressions have been developed for describing the profiles of the substrate concentrations and mass flows in the outer and inner regions of biocatalyst particles, as well as for estimating the influence of internal diffusion on glucose consumption rate. The results indicated that very low values of internal mass flow could be reached in the particles center. The corresponding region was considered biologically inactive, with its extent varying from 0.24% to 44% from the overall volume of each biocatalyst. By immobilization of bacterial cells and use of a basket bed, the rate of glucose consumption is reduced up to 200 times compared with the succinic fermentation system containing free cells.

Biodegradation of lipids from olive oil mill wastewaters in a stationary basket bioreactor with immobilized Bacillus spp. cells - influence of internal diffusion.

The study is focused on the external and internal mass transfers of lipids during their biodegradation process in a bioreactor with stationary basket bed of immobilized Bacillus spp. cells. By means of the lipid mass balance for a single particle of biocatalyst, considering the kinetic model adapted for the immobilized bacterial cells, specific mathematical models have been developed to estimate their mass flows in the liquid boundary layer surrounding the particle and inside the particle. The values of mass flows are significantly influenced by the internal diffusion velocity of lipids and the rate of their consumption, but also by the position inside the basket bed. These influences accumulated led to the appearance of a biological inactive region near the particle centre, its magnitude varying from 1.3 to 49.4% of the overall volume of particles.

[Succinic acid production using mobile bed of immobilized Actinobacillus succinogenes in alginate]. / Obtinerea acidului succinic prin fermentatie cu strat mobil de Actinobacillus succininogenes.

UNLABELLED: This work investigates the production of succinic acid by immobilized A. succinogenes cells, using a bioreactor with stirred/mobile bed of biocatalysts. MATERIAL AND METHOD: The experiments have been carried out for different sizes of biocatalysts particle, under substrate and product inhibitory effects. RESULTS: The results indicated that the inhibitory effects could be diminished by cells immobilization, the substrate consumption rate increasing with the increase of biocatalyst particle size. Moreover, the biocatalysts can be used for many fermentation cycles.

Comparative analysis of oxygen transfer rate distribution in stirred bioreactor for simulated and real fermentation broths.

Study of the distribution of the oxygen mass transfer coefficient, k (l) a, for a stirred bioreactor and simulated (pseudoplastic solutions of carboxymethylcellulose sodium salt) bacterial (P. shermanii), yeast (S. cerevisiae), and fungal (P. chrysogenum free mycelia) broths indicated significant variation of transfer rate with bioreactor height. The magnitude of the influence of the considered factors differed from one region to another. As a consequence of cell adsorption to bubble surface, the results indicated the impossibility of achieving a uniform oxygen transfer rate throughout the whole bulk of the microbial broth, even when respecting the conditions for uniform mixing. Owing to the different affinity of biomass for bubble surface, the positive influence of power input on k (l) a is more important for fungal broths, while increasing aeration is favorable only for simulated, bacterial and yeast broths. The influence of the considered factors on k (l) a were included in mathematical correlations established based on experimental data. For all considered positions, the proposed equations for real broths have the general expression [Formula in text] exhibiting good agreement with experimental results (with maximum deviations of ± 10.7% for simulated broths, ± 8.4% for P. shermanii, ± 9.3% for S. cerevisiae, and ± 6.6% for P. chrysogenum).

External and internal glucose mass transfers in succinic acid fermentation with stirred bed of immobilized Actinobacillus succinogenes under substrate and product inhibitions.

This paper is dedicated to the study on the external and internal mass transfers of glucose for succinic acid fermentation under substrate and product inhibitions using a bioreactor with stirred bed of immobilized Actinobacillus succinogenes cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the kinetic model adapted for both inhibitory effects, specific mathematical models were developed for describing the profiles of the substrate concentration in the outer and inner regions of biocatalysts and for estimating the substrate mass flows in the liquid boundary layer surrounding the particle and inside the particle. The values of the mass flows were significantly influenced by the internal diffusion velocity and rate of the biochemical reaction of substrate consumption. These cumulated influences led to the appearance of a biological inactive region near the particle center, its magnitude varying from 0 to 5.3% of the overall volume of particles.

[Improving the efficacy of synergetically facilitated pertraction of p-aminobenzoic acid by increasing the reextraction rate]. / Marirea eficientei pertractiei facilitate sinergetice a acidului p-aminobenzoic prin cresterea vitezei de reextractie din membrana lichida.

The studies on facilitated pertraction of PABA with Amberlite LA-2 and 1-octanol as phase modifier indicated the increase of the process efficiency and, implicitly, of the transport capacity of the liquid membrane by adding KOH in the stripping phase. Thus, the use of KOH led to the diminution of the kinetic resistance of the reextraction process, with positive effects on the acid final mass flow and permeability factor. Compared to the similar pertraction systems containing NaOH in the stripping phase and in direct correlation with the pertraction parameters (pH-gradient between the feed and stripping phases, carrier and alchohol concentrations inside the liquid membrane), the final mass flow can be accelerated for about 1.9 times, and the permeability through liquid membrane can be enhanced for about 1.5 times in presence of KOH.