A new biotechnological medium for biotransformation of substrates with different water-solubility

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Melania-Liliana ARSENE, Mihaela DONI, Luiza JECU, Emilia OCNARU, Gelu VASILESCU

Reverse micellar system (RMS) provide an excellent medium for nonaqueous biocatalytic studies, being used for enzymatic conversion of aqua-low-solubility reactants. RMS is characterized by hydration degree, w0, defined as the molar ratio of water and surfactant. This parameter induce most of the structural and physico-chemical properties of RMS, being more important even then the absolute quantity of water or surfactant in the system. The reaction of alcohol oxidase from Hansenula polymorpha solubilized in AOT-isooctane reverse micelles was used as a small scale model, both for experimental study and theoretical discussions. The potential of the new reaction medium for biotransformation-catalyzed alcohol oxidase was evaluated using substrates with different hydrophilic / hydrophobic balance. The efficiency of the bioconversion of aliphatic alcohols in RMS has been analyzed.

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Arsene M. L., Doni M., Jecu L., Ocnaru E., Vasilescu G., 2012, A new biotechnological medium for biotransformation of substrates with different water-solubility. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 99-102.

 

A study of stochastic model to predict the growth evolution of food born moulds

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Mioara VARGA, Florentina MATEI, Mala-Maria STAVRESCU-BEDIVAN

Over the last few decades stochastic study in biology has acquired global dimension. The prevention of the food product contamination with toxinogenic moulds is an actuality problem of microbiology. This means that it is necessary to have precise diagnostic methods in order to predict and describe in detail the dynamic of the alteration. Considering all these facts, we tried to develop in our paper a stochastic model to answer to this question. First, we have established some conclusions regarding the growth model; for this, we have made appropriate graphics corresponding evolution strains of Penicillium crysogenum and Fusarium graminearum during the 14 days. Secondly, we have examined the phenomenon of growth as a non-homogeneous Poisson process involving periodic variations in the occurrence rate and we have obtained the probability density function of the time intervals of growth.

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Varga M., Matei F., Stavrescu-Bedivan M. M., 2012, A study of stochastic model to predict the growth evolution of food born moulds. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 182-185.

 

Bio-based composite use in fertilization of petunia and carnation culture

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Gabriela NEAŢĂ, Mona POPA, Amalia MITELUT, Silvana GUIDEA, Bela PUKANSKI

Bio-based composite were used in NPK biodegradable fertilizers. The composition of fertilizers contains 0%, 5%, 10%, 15%, 20% starch from wood flour and the form of them were sticks. For the plant test there were used Petunia hybrid and Dyanthus caryophyllus in 8 cm diameter pots filled with 1:1 peat and garden soil. At every pot was used 0.5 g fertilizer stick. The biodegradable process of sticks determines the slow release of fertilizers in the pot. During vegetation period there were made some biometrical determinations (length, number of shoots) and agrochemical analysis at substrates and plants. Comparison between petunia and carnation development show that petunia answer better at fertilization process. From the point of view of experimental variants the best results were at variants with with 15% and 20% wood flour.

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Neaţă G., Popa M., Mitelut A., Guidea S., Pukanski B., 2012, Bio-based composite use in fertilization of petunia and carnation culture. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 30-35.

 

Biological characterization of some microorganisms of biotechnological interest

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Mihaela-Monica DINU, Cristina FĂTU, Ana-Maria ANDREI

Successful use of biological insecticides depends on their "active substance" quality, which ensures the biological efficacy and performance of bioproducts in field conditions: the active substance have to be virulent and to have ecological competences (epizootiological qualities, multiplication capacity, spreading and persistence in habitats and target pests populations).These parameters are objective criteria for selection of microorganisms that can be successfully included in biological control programs of pests. In this paper are presented results of some laboratory tests aimed to estimate biological parameters specific for entomopathogenic fungi, including the spores germination and spores production on culture media and insects. The biological material used in this study consisted in five Beauveria bassiana entomopathogenic biotypes, isolated from insects belonging to the ord. Coleoptera, Hymenoptera and Diptera in natural epizootic outbreaks, during the years 2008-2010. The results led to the following conclusions: (i) B. bassiana strains having different origins in terms of habitat and host insect exhibit different biological qualities, (ii) the evaluation of test insects mortality induced by B. bassiana doesn’t provides a complete pathological characterization of fungal isolates; to assess the biological control potential of B. bassiana isolates, the virulence have to be correlated with the biological cycle of the fungus and the spores production on the insect cuticle; (iii) the quantification of spore production on insect is also necessary to further evaluate the fungal strains potential to naturally increase of virulence.

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Dinu M. M., Fătu C., Andrei A. M., 2012, Biological characterization of some microorganisms of biotechnological interest. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 15-21.

 

Biotechnology of submerged fermentation to produce nutritive mycelial biomass through controlled cultivation of edible and medicinal mushrooms

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Marian PETRE, Alexandru TEODORESCU, Florin PĂTRULESCU

The main aim of this research work was focused on the establishment of the best food biotechnology in order to be applied in the leading and controlling of submerged fermentation by using three edible and medicinal mushroom species Ganoderma lucidum (Curt. Fr.) P. Karst and Lentinula edodes (Berkeley) Pegler that were grown on different substrata containing grain wastes as main constituents. The experiments were carried out by cultivating these mushroom species under controlled conditions inside the culture vessel of a modern laboratory-scale bioreactor designed at the highest food quality standards. The submerged fermentation was set up in the following conditions: temperature,25- 27° C; agitation speed, 100-120 rev. min -1; pH level, 5.7 – 6.5 units; dissolved oxygen tension within the range of 30% - 70%. During the period of controlled submerged fermentation lasting from 120 to 170 h, the mycelial biomass of fungal pellets was developed inside the broth. At the end of the culture cycles, the fungal pellets were harvested by extracting them from the culture vessel of the bioreactor and separating them from the broth by slow vacuum filtration. Pellet size, the hairy length of pellets, and the free mycelia fraction in the total biomass were microscopically investigated and the chemical composition of fungal biomass was analysed to determine and compare the protein and reduced sugar contents.

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Petre M., Teodorescu A., Pătrulescu F., 2012, Biotechnology of submerged fermentation to produce nutritive mycelial biomass through controlled cultivation of edible and medicinal mushrooms. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 89-93.

 

Colonization and degradation of polyethylene composites by fungal strains isolated

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Mariana CONSTANTIN, Iuliana RAUT, Gelu VASILESCU, Melania Liliana ARSENE, Luiza JECU

Polyethylene is one of the most inert plastic materials characterized by a high molecular weight, complex three dimensional structures and hydrophobic nature. These features interfere with its availability to microorganisms and cause serious environmental problems. One of the viable alternatives to accelerate the attack of microorganisms to LDPE is the addition of natural polymers; like starch, wood flour or cellulose fibers to guarantee at least a partial biodegradation. Wood flour is considered an excellent fillers for LDPE because of their low density, low cost, high strength, desirable fiber aspect ratio, flexibility during processing and biodegradability. The objective of this study is to investigate polyethylene based composites biodegradability. Several fungal strains were isolated after exposure period to soil burial tests. Strains from existing microbial collection were also tested. Polyethylene degradation ability of microorganisms was evaluated by weight loss and scanning electron microscopic (SEM) study of plastic strips after 3 months incubation in pure shake culture conditions. SEM analysis showed a thick network of fungal hyphae forming a biofilm on the surface of the plastic pieces. The colonization extent varied from strain to strain. There was observed a small difference but no significant in the weight of polyethylene composites before and after incubation with microorganisms. Strains tested are capable to form an adherent biofilm on the surface of LDPE composites. It is a slow process but these experiments give the evidences of biodegradation of LDPE composites.

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Constantin M., Raut I., Vasilescu G., Arsene M. L., Jecu L., 2012, Colonization and degradation of polyethylene composites by fungal strains isolated. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 109-112.

 

Comparative study of the antioxidants content in some berries fruits

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Gabriela LUŢĂ, Florentina ISRAEL-ROMING, Daniela BĂLAN, Evelina GHERGHINA, Nicolae GONŢEA, Mihai CURTAŞU

Berries fruits contain many different chemical compounds with different biological and pharmacological capacities and properties. So, these fruits are a source of bioactive molecules with antioxidant activity such as phenolic compounds, flavonoids, anthocyanins, ascorbic acid, that are important to human nutrition. Antioxidants neutralize free radicals, which cause oxidative damage to lipids, proteins, and nucleic acids and thus protect the organism. Research studies carried out on this topic indicated that natural antioxidants are involved in protection against many deseases: cancer, cardiovascular deseases, osteoporosis. The objective of this research was to determine and compare the antioxidants content offered by six berries fruits species: raspberry (Rubus idaeus), blackberry (Rubus fructicosus), strawberry (Fragaria ananassa), chokeberry (Aronia melanocarpa), blackcurrant (Ribes nigrum), sea-buckthorn (Hippophaea rhamnoides). The evaluation involved determination of total phenols, anthocyanins and flavonoids, using spectrophotometrical methods. Higher total phenol content levels were obtained in chokeberries and in blackcurrants.

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Luţă G., Israel-Roming F., Bălan D., Gherghina E., Gonţea N., Curtaşu M., 2012, Comparative study of the antioxidants content in some berries fruits. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 86-88.

 

Comparing some characteristics of fresh, frozen and canned strawberries

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Raluca NĂSTASE, Mira TURTOI, Mihaela GHIDURUS

We evaluated sensorial, physic-chemical and microbiological characteristics of fresh, frozen and canned strawberries. The sensorial analysis consisted in aspect, aroma and texture evaluation; the physic-chemical parameters analysed were: pH and water activity and the microbiological parameters were yeasts and moulds. All samples were purchased from the market, frozen strawberries packed in plastic bags, in air atmosphere and canned strawberries packed in metal recipients, in sugar syrup. Sensorial analysis was made by untrained panellists. All samples were smashed into a Stomacher before analysing from the physic-chemical and microbiological point of view. pH was determined using a INOLAB 720 WTW series pH-meter equipped with a Sen Tix Sp Spear immersion electrode and water activity was analysed using a Novasina LabMaster AW device. Yeasts and moulds number was evaluated using SR ISO 7954. From the sensorial point of view, fresh strawberries had the highest scores for aspect and texture and the most tasteful sample was canned strawberries due to sugar syrup. Most acid samples were those of frozen strawberries and most basic ones were those of canned strawberries. Water activity registered the highest value for fresh strawberries and for canned and frozen samples values were very similar. Yeasts and moulds had the lowest values for canned strawberries, followed by frozen and fresh strawberries.

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Năstase R., Turtoi M., Ghidurus M., 2012, Comparing some characteristics of fresh, frozen and canned strawberries. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 156-159.

 

Defense response induced in tomato plants (Lycopersicon Esculentum) by microbial infections

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Gabriela POPA, Loredana POHRIB, Călina Petruţa CORNEA

Most of the microorganisms associated with plants are pathogens so plants generally respond to pathogen infections by using their defensive system. Plant pathogen-related (PR) proteins including peroxidase, .-1,3-glucanase, phenylalanine ammonia-lyase and chitinase are proteins that are induced as result of pathogen infections. Chitinases and .-1,3-glucanase can degrade the cell walls of some plant pathogens and that may play a role in the host plant’s defensive system. In our experiments we used Bacillus licheniformis designated as Bw, that shown antagonistic activities against various fungal pathogens including Rhizoctonia solani that cause Damping–Off of tomato. Soil application on tomato seedling roots (var. Marmade) of R. solani alone and B. licheniformis in combination with R. solani induced a significant increase in the activities of .-1,3-glucanase and phenylalanine ammonia-lyase (PAL). Peroxidase activity in both fungal and bacterial treatments was also significantly stimulated. In contrast, peroxidase activity was reduced upon inoculation of plants with a mixture of B. licheniformis- R. solani. Results indicated that PR proteins were induced in all treatments with pathogenic or non-pathogenic microorganisms.

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Popa G., Pohrib L., Cornea C. P., 2012, Defense response induced in tomato plants (Lycopersicon Esculentum) by microbial infections. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 45-49.

 

Ecological products for agriculture

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Nicoleta RADU, Ana Aurelia CHIRVASE, Nela ZAMBILA

This paper aims to reduce the environmental pollution caused by fertilizer use in agriculture by chemical synthesis, by identifying suitable technologies and biological products to be used to fertilize soil in Romania. An alternative to limiting pollution from synthetic fertilizers and pesticides is to use in agriculture some products based on bacteria, bacterial consortia or biomass with plant or animal origin. The microbial fertilisers shall be characterized in terms of

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Radu N., Chirvase A. A., Zambila N., 2012, Ecological products for agriculture. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 56-62.

 


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