pinecone/core-2020-05-10-deduplication huggingface dataset:
Batch production of L(+) lactic acid from whey by Lactobacillus casei (NRRL B-441)

The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 °C and pH 5.5. The productivity was 1.87 g dm-3 h-1 at 37 °C in shake flasks. In the fermenter, a productivity of 3.97 g dm-3 h-1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm-3. Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO4·H2O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose-1
Assessment of yeast viability under hyperbaric conditions through a modeling approach

The effect of pressure (0.1–1.5 MPa) and oxygen concentration on the growth and viability of Saccharomyces cerevisiae was studied. Cell viability was assessed through the Methylene Blue staining method and the percentages of viable and non-viable cells were estimated using digital image processing.
A model taking into account cell viability was developed and used to describe the measured data. The model reveals the opposing effects between oxygen availability and the baric and oxidative stresses present
on the system and can successfully describe not only the traditional biomass–product–substrate (X–P–S) volution but also the ratio of viable cells with time. It is shown that cell viability in general is not constant during the experiments but strongly depends on the environment
Bioprocesses for the removal of nitrogen oxides from polluted air

Nitrogen oxides (NOx) of environmental concern are nitrogen monoxide (NO) and nitrogen dioxide (NO2). They are hazardous air pollutants that lead to the formation of acid rain and tropospheric ozone. Both pollutants are usually present simultaneously and are, therefore, called NOx. Another compound is N2O which is found in the stratosphere where it plays a role in the greenhouse effect. Concern for environmental and health issues coupled with stringent NOx emission standards generates a need for the development of efficient low-cost NOx abatement technologies. Under such circumstances, it becomes mandatory for each NOx-emitting industry or facility to opt for proper NOx control measures. Several techniques are available to control NOx emissions: selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), adsorption, scrubbing, and biological methods. Each process offers specific advantages and limitations. Since bioprocesses present many advantages over conventional technologies for flue gas cleaning, a lot of interest has recently been shown for these processes. This article reviews the major characteristics of conventional non-biological technologies and recent advances in the biological removal of NOx from flue gases based on the catalytic activity of either eucaryotes or procaryotes, ie nitrification, denitrification, the use of microalgae, and a combined physicochemical and biological process (BioDeNOx). Relatively uncomplicated design and simple operation and maintenance requirements make biological removal a good option for the control of NOx emissions in stationary sources
Autotrophic deodorization of hydrogen sulfide in a biotrickling filter

The removal of hydrogen sulfide (H2S) from airstreams was studied in a biotrickling filter (BTF) packed with plastic Pall rings operating with counter-current flows of the air and liquid streams. Experiments were performed at different inlet H2S concentrations, air and/or liquid volumetric flow rates, and sulfate concentrations in the recirculating liquid to check their effect on the performance of the BTF. Conversion of H2S never dropped below 80% at the highest concentration and reached 100% at low concentrations. A maximum removal rate of 22.5 g H2S m−3 reactor h−1 was observed with 100% removal efficiency. The shortest empty bed retention time studied at which complete H2S removal was observed was around 11 s. Conversion of H2S was found to slightly increase as the liquid flow rate decreased and as the air flow rate increased
Optimization of lactic acid production from whey by L casei NRRL B-441 immobilized in chitosan stabilized Ca-alginate beads

The production of lactic acid from whey by Lactobacillus casei NRRL B-441 immobilized in chitosan-stabilized Ca-alginate beads was investigated. Higher lactic acid production and lower cell leakage were observed with alginate-chitosan beads compared with Ca-alginate beads. The highest lactic acid concentration (131.2 g dm-3) was obtained with cells entrapped in 1.3-1.7 mm alginate-chitosan beads prepared from 2% (w/v) Na-alginate. The gel beads produced lactic acid for five consecutive batch fermentations without marked activity loss and deformation. Response surface methodology was used to investigate the effects of three fermentation parameters (initial sugar, yeast extract and calcium carbonate concentrations) on the concentration of lactic acid. Results of the statistical analysis showed that the fit of the model was good in all cases. Initial sugar, yeast extract and calcium carbonate concentrations had a strong linear effect on lactic acid production. The maximum lactic acid concentration of 136.3 g dm-3 was obtained at the optimum concentrations of process variables (initial sugar 147.35 g dm-3, yeast extract 28.81 g dm-3, CaCO3 97.55 g dm-3). These values were obtained by fitting of the experimental data to the model equation. The response surface methodology was found to be useful in optimizing and determining the interactions among process variables in lactic acid production using alginate-chitosan-immobilized cells
Optimisation of a serine protease coupling to Eudragit S-100 by experimental design techniques

A full factorial design was used to study the influence of four different variables, namely polymer concentration, carbodiimide concentration, time of reaction and blocking agent concentration, on the coupling of a serine protease into a soluble–insoluble polymer (Eudragit S-100). All of the four factors studied have played a critical role in the protease coupling. Response surface methodology was used as an optimisation strategy to attain a conjugate with high activity yield and operational stability at 60 ◦C.
Under optimised conditions (Eudragit, 2.5% w/v, carbodiimide, 0.2% w/v, coupling time, 1 h and blocking agent concentration, 0.05%), the conjugate activity yield was about 45% and its operational stability at 60 ◦C was increased by 1.7 times. After reusing the conjugate for five cycles, the remaining activity was still 72% of the initial value when compared with the native enzyme. Several tests confirmed that the enzyme was covalently crosslinked to Eudragit, which represents an improvement in the carbodiimide coupling of proteases into soluble–insoluble polymers
Formaldehyde biodegradation in the presence of methanol under denitrifying conditions

Simultaneous formaldehyde and methanol biodegradation and also denitrification were studied in batch assays and in a continuous laboratory-scale reactor. In batch assays, high formaldehyde concentrations (up to 1360 mg dm−3) were removed under anoxic conditions in the presence of methanol. It was found that formaldehyde biodegradation produced methanol and formic acid as products. The denitrification process was affected by the initial formaldehyde concentration. In the continuous reactor, the biodegradation of different concentrations of formaldehyde (1500–275 mg dm−3) and methanol (153–871 mg dm−3) took place, maintaining the organic loading rate at 0.84 g COD dm−3 d−1 (COD/N 4). However, each increase in the methanol concentration in the influent caused a decrease in the denitrification level. An adaptation period to methanol was necessary before the denitrification percentage could be recovered. In contrast with batch assays, in the continuous reactor methanol and formic acid were not detected in the effluent. Moreover, in the continuous reactor the denitrification percentages were higher and the nitrite accumulation was lower
Effect of inoculation dosing on the composting of source-selected organic fraction of municipal solid wastes

The effects of a commercial inoculum (MicroGest 10X, Brookside Agra L.C.) on the field-scale composting of the source-selected organic fraction of municipal solid wastes (OFMSW) have been studied by following routine parameters of the composting process (temperature, oxygen content and moisture) and biologically-related tests such as the respirometric index and the maturity grade. The inoculum was added to composting piles of OFMSW at different levels: control (no added inoculum), treatment A (10⁵ CFU g⁻¹ of OFMSW), treatment B (10⁶ CFU g⁻¹ of OFMSW) and treatment C (10⁷ CFU g⁻¹ of OFMSW). The inoculum selected produced a significant acceleration of the composting process with high levels of biological activity in the thermophilic phase. In terms of the acceleration of composting and economy the optimal treatment was B, which produced a reduction of approximately half of the total composting time. Treatment C did not improve significantly the results obtained with treatment B, whereas treatment A has little effect on the composting of OFMSW when compared with the control experiment. Respirometric index (determined at 55 °C) and maturity grade appeared to be the most reliable tests to follow the biological activity of the composting of OFMSW. On the other hand, routine parameters such as temperature, oxygen content and moisture showed no significant differences among the different inoculation levels tested in the composting process
Kinetic modelling of lactic acid production from whey by Lactobacillus casei (NRRL B-441)

The biomass growth, lactic acid production and lactose utilisation kinetics of lactic acid production from whey by Lactobacillus casei was studied. Batch fermentation experiments were performed at controlled pH and temperature with six different initial whey lactose concentrations (9-77 g dm-3) in a 3 dm3 working volume bioreactor. Biomass growth was well described by the logistic equation with a product inhibition term. In addition, biomass and product inhibition effects were defined with corresponding power terms, which enabled adjustment of the model for low- and high-substrate conditions. The Luedeking-Piret equation defined the product formation kinetics. Substrate consumption was explained by production rate and maintenance requirements. A maximum productivity of 2.5 g dm-3 h-1 was attained with an initial lactose concentration of 35.5 g dm-3
A novel silk fibroin-supported ironcatalyst for hydroxylation of phenol

The aim of this study was to explore the potential use of silk fibroin (SF) as a catalyst support material for phenol hydroxylation reactions. Iron-substituted silk fibroin fibers were prepared using formic acid at room temperature and characterized using inductively coupled plasma atomic-emission spectrometry, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and optical microscopy. Measurement of an FTIR spectrum showed that the secondary structure was β-structure before and after iron substitution. To evaluate the catalytic properties of prepared catalyst, phenol hydroxylation reaction was carried out using aqueous hydrogen peroxide as an oxidant. An excellent transformation of phenol into dihydroxybenzenes (catechol and hydroquinone) was achieved. Phenol conversions of 3.3%, 61.2%, and 80.3% were obtained at room temperature, 40°C and 60°C respectively. It was found that no further phenol conversion proceeded because catalysts became separated from the reaction system during the reaction. No significant leaching of the iron was detected. Catalyst could be reused several times without a significant change in activity. Parent silk fibroin fibers without iron were inactive.İYT
Enhanced biological treatment of spent metalworking fluids by prior removal of a polymer

The biological treatment of spent synthetic metalworking fluid (MWF) has been investigated in many studies, with most reporting the presence of undegraded components in the residual waste. In this study a hybrid approach to waste treatment of spent MWF, involving both physical treatment and microbial degradation, was investigated. The effect of the removal of a synthetic polymer on biological degradation was investigated in a bioreactor system. Polymer removal was found to have little effect on the degradation efficiency of the remaining components but resulted in a waste product with 14% lower chemical oxygen demand. An additional benefit of this approach is that it enables the possibility of recycling of the recovered components, with the aim of economising on future product formulation and reducing waste discharg
Effects of bioaugmentation by an anaerobic lipolytic bacterium on anaerobic digestion of lipid-rich waste

The effect of bioaugmentation with an anaerobic lipolytic bacterial strain on the anaerobic digestion of restaurant lipid-rich waste was studied in batch experiments with a model waste containing 10% lipids (triolein) under two sets of experimental conditions: (A) methanogenic conditions, and (B) initially acidogenic conditions in the presence of only the lipolytic strain biomass (4 days), followed by methanogenic conditions. The bioaugmenting lipolytic strain, Clostridium lundense (DSM 17049T), was isolated from bovine rumen. The highest lipolytic activity was detected at the beginning of the experiments. A higher methane production rate, 27.7 cm3 CH4(STP) g-1 VSadded day-1 (VS, volatile solids) was observed in experiment A with the presence of the bioaugmenting lipolytic strain under methanogenic conditions. The highest initial oleate concentration, 99% of the total oleate contained in the substrate, was observed in the experiments with the bioaugmenting lipolytic strain under treatment A conditions; the levels of palmitate and stearate were also higher until day 15, indicating that the bioaugmentation strategy improved the hydrolysis of the lipid fraction. In general, the results indicated that degradation of the long chain fatty acids (LCFAs) controlled the digestion process.Swedish
Energy Agency ; Fundação para a Ciência e a Tecnologia (FCT
Motion of a magnetic flow follower in two-phase flow: application to the study of airlift reactor hydrodynamics

A low-cost and simple magnetic particle tracer method was adapted to characterize the hydrodynamic behavior of an internal- and an external-loop airlift reactor (ALR). The residence time distribution of three magnetic particles differing in diameter (5.5, 11.0 and 21.2mm) and with a density very close to that of water was measured in individual reactor sections. The measured data were analyzed and used to determine the velocity of the liquid phase. Validation of the experimental results for liquid velocity was done by means of the data obtained by an independent reference method. Furthermore, analysis of the differences found in the settling velocity of
the particle in single-liquid and gas-liquid phases was carried out, using a simplified 3D momentum transfer model. The model considering particle-bubble interaction forces resulting from changes in the liquid velocity
field due to bubble motion was able to predict satisfactorily the increase in the particle settling velocity in the homogeneous bubbly regime. The effective drag coefficient in two-phase flow was found to be directly dependent on particle Reynolds number to the power of - 2 but independent of gas flow-rate for all particle diameters studied. Based on the experimental and theoretical investigations, the valid exact formulation of the effective buoyancy force necessary for the calculation of the correct particle settling velocity in two-phase flow was done. In
addition, recommendations concerning the use of flow-following particles in internal-loop ALRs for liquid velocity measurements are presented.Fundação para a Ciência e a Tecnologia (FCT)University of Alcalá de Henare
Comparative study of poly(vinyl alcohol)-based support materials for the immobilization of glucose oxidase

BACKGROUND: The performances of four types of glucose oxidase (GOD) immobilization materials based on poly(vinyl alcohol) (PVA) were compared. The matrices of interest were chernically-linked PVA, freeze-thawed PVA cryogel, tetramethoxysilane (TMOS) sol-gel-PVA hybrid material, and alumina sol-gel-PVA hybrid material.\ud
RESULTS: Overall, the membranes showed good sensitivity except for the chemically cross-linked PVA. However, the main differences with the enzyme immobilization methods were enzyme leakage and values of K-m(app).\ud
CONCLUSION: Freeze-thawed PVA-GOD membranes and TMOS-PVA, which showed satisfactory sensitivity and adequate value of K-m(app), were quite promising as support materials for immobilizing GOD. (c) 2007 Society of Chemical Industry
Unstructured mathematical model for biomass, lactic acid and bacteriocin productions by lactic acid bacteria in batch fermentation

6 páginas, 3 figuras, 2 tablasBACKGROUND: A simple macroscopical model was proposed to describe the fermentation kinetics of growth, bacteriocins and lactic acid production by Lactococcus lactis and Pediococcus acidilactici in a batch system. The equations used were: the logistic reparametrized for growth, the Luedeking–Piret model for bacteriocin production, the maintenance energy model for glucose consumption; and the homofermentative balance equation for lactic acid formation.\ud
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RESULTS: In all the cultures, the mathematical models, consistents and robusts, adjusted, perfectly, the experimental kinetic profiles. Also, the corresponding kinetic parameters were significant, so much biological as statistically.\ud
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CONCLUSIONS: The group of integrated equations used, besides showing high accuracy in predicting the studied bioproductions, established a useful tool for the control of lactic acid bacteria kinetics in bioreactors in terms of its statistical consistency. Copyright © 2007 Society of Chemical IndustryPeer reviewe
On the application of 'seeding' techniques in the primary separation of plasmid DNA from neutralised E-coli lysates

This is a preprint of an article published in the Journal of Chemical Technology and Biotechnology at http://onlinelibrary.wiley.com/doi/10.1002/jctb.1834/abstract.BACKGROUND: Initial extraction of plasmid DNA from Escherichia coli and its separation from host-derived contaminants is a difficult task to perform. Here, we examine the application of particle ‘seeding’ solid-liquid separation methods for primary recovery of plasmid DNA from neutralised alkaline cell lysates.\ud
RESULTS: Planting magnetic particle ‘seeds’ during cell lysis resulted in enhanced phase separation, facile magnetic separation of the floc, slight improvements in plasmid purity, but diminished plasmid recoveries. When CaCO3-coated low-density microspheres were seeded into flocs, phase separation was impaired, shear-induced floc damage and contamination of the plasmid liquor with genomic DNA and cell debris occurred, but plasmid DNA recovery was improved. Introduction of hydrophobic low-density microspheres into the floc dramatically improved floc stiffness, phase separation and\ud
flotation efficiency, and reduced the solids content in the plasmid liquor ten-fold. However, strong reinforcement of the cell debris lattice by these microspheres hindered plasmid release into the liquor beneath. CONCLUSION: By incorporating magnetic or buoyant seeds during cell lysis we have identified new routes for separation of shear-sensitive cell debris solids from crude plasmid containing liquors. Effective use of seeding approaches for difficult solid-liquid separation tasks will require evaluation of a wide range of seeds of varying architecture, size, shape, density and chemistry
Colloid deposition experiments as a diagnostic tool for biomass attachment onto bioproduct adsorbent surfaces

Background: Detrimental processing conditions can be expected in any downstream operation where direct contacting between a crude feedstock and a reactive solid phase is supposed to occur. In this paper we have investigated the factors influencing intact yeast cells deposition onto anion and cation exchangers currently utilized for expanded-bed adsorption of biotechnological products. The aim of this study was twofold: (a)to confirm previous findings relating biomass deposition with surface energetics according to the extended Derjaguin, Landau, Verwey and Overbeek theory (XDLVO) theory; and (b) to provide a simple experimental tool to evaluate biomass deposition onto process surfaces. Results: Biomass deposition experiments were performed on an automated workstation utilizing a packedbed format. Two commercial ion exchangers intended for the direct capture of bioproducts in the presence of suspended biological particles were employed. Intact yeast cells in the late exponential phase of growth were selected as model bio-colloids. Cell deposition was systematically evaluated as a function of fluid-phase conductivity and quantitatively expressed as a biomass deposition parameter (α). Conclusion: α ≤ 0.15 was established as a criterion to reflect negligible biomass adhesion to the process support(s). Biomass deposition experiments further confirmed predictions made on the basis of free interfacial energy calculations as per the extended DLVO approach.Inter-American Development Bank (BID) 1201/OC AR 649 PICT 08352; Jacobs University (IUB/2130-90050) and TÜBİTA
Levels of ATP in different organic wastes under composting conditions

Background: the concentration of ATP in selected samples from the composting process of several organic wastes (municipal solid wastes, wastewater sludge, animal by-products and cow manure) has been determined in order to characterize the aerobic biological activity of such wastes. Results: the values obtained ranged from 0 (in old stable compost from cow manure) to 0.07 μ mol ATP/g dry matter in thermophilic samples of municipal solid wastes composting. In general, it was found that ATP levels were in agreement with the stage of the composting process (initial stage, thermophilic period and maturation). On the other hand, ATP concentration correlated well (p<0.05)  with the overall respiration activity during a whole composting process of municipal solid waste at full scale. Conclusion: ATP concentration can be used to determine the biological activity of organic solid wastes in different stages of their biological treatment and to predict compost stability prior to soil application
The use of olive mill wastewater by wild type Yarrowia lipolytica strains : medium supplementation and surfactant presence effect

BACKGROUND: The aim of this work was to study the ability of two different wild type strains of the yeast Yarrowia lipolytica to grow on olive mill wastewater (OMW) and their potential to produce high-value products such as lipases. Factors that affect cellular growth and OMW degradation were studied, such as nitrogen supplementation, cells concentration and surfactant addition.
RESULTS: Both strains, W29 and IMUFRJ 50682, were able to grow in OMW with 19 g L-1 of COD and approximately 800 mg L-1 of total phenols concentration. The strain W29 presented the highest potential for extracellular lipase production in OMW medium. Lipase productivity was improved by the medium supplementation with ammonium sulphate up to 6 g L-1, leading to 80% of COD degradation and 70% of total phenols reduction. The surfactant Tween 80 enhanced cell growth and COD degradation, but had a negative effect on lipase activity.
CONCLUSIONS Y. lipolytica has a great potential for OMW valorisation by its use as culture medium for biomass and enzymes production. The operating conditions that favoured lipase production differ from the conditions that improve COD reduction.Fundação para a Ciência e a Tecnologia (FCT