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Modelling of Ethanol Production from Red Beet Juice by Saccharomyces cerevisiae under Thermal and Acid Stress Conditions

Donaji Jiménez-Islas
1, Jesús Páez-Lerma2, Nicolás Oscar Soto-Cruz2 and Jorge Gracida1,3*

1
Department of Biotechnology, Polytechnic University of Pachuca, Ex–Hacienda de Santa Bárbara,
Carretera Pachuca–Cd. Sahagún Km. 20, Zempoala, 43830 Hidalgo, Mexico

2Department of Chemical and Biochemical Engineering, Technological Institute of Durango, Blvd. Felipe Pescador 1830 Oriente, 34080 Durango, Mexico
3Department of Biotechnology, Autonomous University of Queretaro, Cerro de Las Campanas, 76010 Queretaro, Mexico

Article history:

Received December 5, 2012

Accepted January 16, 2014

Key words:
Beta vulgaris
L., modelling parameters, logistic, Pirt and Luedeking-Piret equations

Summary:

In this work the effects of pH and temperature on ethanol production from red beet
juice by the strains Saccharomyces cerevisiae ITD00196 and S. cerevisiae ATCC 9763 are studied. Logistic, Pirt, and Luedeking-Piret equations were used to describe quantitatively the microbial growth, substrate consumption, and ethanol production, respectively. The two S.cerevisiae strains used in this study were able to produce ethanol with high yield and volumetric productivity under acid and thermal stress conditions. The equations used to model the fermentation kinetics fit very well with the experimental data, thus establishing that ethanol production was growth-associated under the evaluated conditions. The yeast S. cerevisiae ITD00196 had the best fermentative capacity and could be considered as an interesting option to develop bioprocesses for ethanol production.

 

 

*Corresponding author:       
                                                    
     +52 442 192 1200, Ext. 5557

                                            +52 442 192 1200, Ext. 5570

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Thermodynamic Properties, Sorption Isotherms and Glass Transition Temperature of Cape Gooseberry (Physalis peruviana L.)

Antonio Vega-Gálvez1, Jessica López1, Kong Ah-Hen2*, María José Torres1 and Roberto Lemus-Mondaca1

1
Food Engineering Department, La Serena University, Raúl Bitrán Avenue, La Serena,
Region of Coquimbo, Chile

2Institute of Food Science and Technology, Austral University of Chile, Julio Sarrazín Avenue, Valdivia, Region de los Ríos, Chile

Article history:

Received March 26, 2013
Accepted October 1, 2013

Key words:

Cape gooseberry, sorption isotherm, modelling, isosteric heat, glass transition temperature, Gordon-Taylor model

Summary:

Adsorption and desorption isotherms of fresh and dried Cape gooseberry (Physalis peruviana L.) were determined at three temperatures (20, 40 and 60 ºC) using a gravimetric technique. The data obtained were fitted to several models including Guggenheim-Anderson-De Boer (GAB), Brunauer-Emmett-Teller (BET), Henderson, Caurie, Smith, Oswin, Halsey and Iglesias-Chirife. A non-linear least square regression analysis was used to evaluate the models. The Iglesias-Chirife model fitted best the experimental data. Isosteric heat of sorption was also determined from the equilibrium sorption data using the Clausius-Clapeyron equation and was found to decrease exponentially with increasing moisture content. The enthalpy-entropy compensation theory was applied to the sorption isotherms and indicated an enthalpy-controlled sorption process. Glass transition temperature (Tg) of Cape gooseberry was also determined by differential scanning calorimetry and modelled as a function of moisture content with the Gordon-Taylor, the Roos and the Khalloufi models, which proved to be excellent tools for predicting glass transition of Cape gooseberry.


 

*Corresponding author:      kshun@uach.cl   
                                                   +56 63 221 302
                                          
+56 63 221 355

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Parent-Offspring Relationships Following Mass Spawning of Wild Adriatic Sea Bass (Dicentrarchus labrax)

Jelena Lončar1, Renata Barić2, Lav Bavčević3 and Branko Kozulić1*


1
Gentius d.o.o, Petra Kasandrića 6, HR-23000 Zadar, Croatia

2Cromaris d.d., Gaženička cesta 4b, HR-23000 Zadar, Croatia
3Croatian Agricultural Advisory Service, Ivana Mažuranića 30, HR-23000 Zadar, Croatia

Article history:

Received May 14, 2013

Accepted: December 18, 2013

Key words:

sea bass, selective breeding, genotyping, microsatellites

Summary:

We have genotyped 44 fishes caught in the wild (Novigrad Sea, Croatia) using 11
microsatellite tetranucleotide markers. They were divided in two groups and after natural mass spawning, we selected 500 offspring for genotyping following their labelling withn electronic tags. All fish in the parental group could be identified based on unique genotypes, and a significant number of private alleles, the alleles found only in one fish, greatly facilitated subsequent parent-offspring assignments. The majority of potential parents left no progeny, while just six of them generated over 70 %. Such highly skewed reproduction success, observed also in other studies, can quickly lead to a highly inbred population in just a few selection cycles. This kind of genetic analysis is helpful for planning of future selective breeding, where faster progress will be made possible based on the soon to be completed sea bass genome sequence.

 

 

*Corresponding author:        branko.kozulic@yahoo.com
                                                          +385 23 331 077

                                            +385 23 331 08

 


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Screening for Extracellular Lipase Enzymes with Transesterification Capacity in Mucoromycotina Strains

Alexandra Kotogán, Brigitta Németh, Csaba Vágvölgyi, Tamás Papp and Miklós Takó*


Department of Microbiology, Faculty of Science and Informatics, University of Szeged,
Közép fasor 52, HU-6726 Szeged, Hungary

Article history:

Received June 3, 2013

Accepted January 30, 2014

Key words:

zygomycetes, tributyrin, wheat bran, p-nitrophenyl palmitate, transesterification

Summary:

In this study, 169 zygomycetes fungal strains including some cold-tolerant isolates
were screened for their extracellular lipolytic activity towards tributyrin. Nineteen of them were outstanding in their enzyme production as they developed the largest lipolytic halo around the colonies in plate tests. Mortierella alpina, M. echinosphaera, Mucor corticolus, Rhizomucor miehei, Rhizopus oryzae, Rh. stolonifer, Umbelopsis autotrophica, U. isabellina, U. ramanniana var. angulispora and U. versiformis were selected for further studies to characterise their lipolytic enzyme production in detail. In these assays, effect of Tween 80 and palm, soybean, sunflower, olive, extra virgin olive, wheat germ, corn germ, sesame seed, pumpkin seed and cottonseed oils on the enzyme activities was investigated, and wheat bran-based submerged and solid-state fermentations were also tested. Tween 80 and olive oil proved to be efficient inductors for lipolytic enzyme production, which was also enhanced when wheat bran was used as support. Addition of mineral salts and olive oil to the solid fermentation medium resulted in at least 1.5-fold increment in the enzyme activities of the crude extracts. Organic synthesis was also assayed by the selected lipases, in which enzymes from the fungi R. miehei, Rh. stolonifer and M. echinosphaera gave the best yields during transesterification reactions between p-nitrophenyl palmitate and ethanol.

 

 

*Corresponding author:        tako78@bio.u-szeged.hu
                                                          +36 62 544 516

                                            +36 62 544 823

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Flavonoids as Inhibitors of Human Butyrylcholinesterase Variants

Maja Katalinić§, Anita Bosak§ and Zrinka Kovarik*


Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia

Article history
:

Received March 25, 2013
Accepted September 23, 2013

Key words:

cholinesterase, reversible inhibition, galangin, quercetin, fisetin, luteolin

Summary:

The inhibition of butyrylcholinesterase (BChE, EC 3.1.1.8) appears to be of interest in
treating diseases with symptoms of reduced neurotransmitter levels, such as Alzheimer’s disease. However, BCHE gene polymorphism should not be neglected in research since it could have an effect on the expected outcome. Several well-known cholinergic drugs (e.g. galantamine, huperzine and rivastigmine) originating from plants, or synthesised as derivatives of plant compounds, have shown that herbs could serve as a source of novel target-directed compounds. We focused our research on flavonoids, biologically active polyphenolic compounds found in many plants and plant-derived products, as BChE inhibitors. All of the tested flavonoids: galangin, quercetin, fisetin and luteolin reversibly inhibited usual, atypical, and fluoride-resistant variants of human BChE. The inhibition potency increased in the following order, identically for all three BChE variants: luteolin<fisetin< quercetin<galangin. The determined enzyme-inhibitor dissociation constants (Ki) ranged from 10 to 170 μmol/L. We showed that no significant change in the inhibition potency of selected flavonoids exists in view of BChE polymorphism. Our results suggested that flavonoids could assist the further development of new BChE-targeted drugs for treating symptoms of neurodegenerative diseases and dementia.

 

 

*Corresponding author:        zkovarik@imi.hr                                        
                                       
   +385 1 4682 555
                                            +385 1 4673 303

§Both authors contributed equally to this work


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