ISSN 2285-1364, ISSN CD-ROM 2285-5521, ISSN ONLINE 2285-1372, ISSN-L 2285-1364
 

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Mihaela Marilena STANCU

Crude oil extraction, transportation and storage facilities are frequently the source of soil and water pollution in Romania. Rhodococcus sp. Po4 showed good tolerance to both 1 % (v/v) alkanes (cyclohexane, nhexane, n-decane) and aromatics (toluene, styrene, ethylbenzene) with log POW (logarithm of the partition coefficient of the solvent in n-octanol-water mixture) values between 2.64 and 5.98. However, 1 % (v/v) alkanes were less toxic for Rhodococcus sp. Po4 cells, compared with 1 % (v/v) aromatics. The high organic solvent tolerance of Rhodococcus sp. Po4 could be due to the presence in their large genome of some catabolic and trehalose-6-phosphate synthase genes. In addition, Rhodococcus sp. Po4 exhibits potential to synthesize carotenoid pigments which can improve the cell membrane impermeability to toxic organic solvents.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Oana-Alina SICUIA, Sorina DINU, Mihaela DINU, Cristina FĂTU, Daria VĂLIMAREANU, Carmen MINCEA, Florica CONSTANTINESCU

Pest and disease management using biocontrol microbial strains is a request of the organic agriculture or a phytosanitary alternative that can decrease chemical inputs in the integrated agricultural systems. Biocontrol bacteria of Bacillus spp. proved to suppress soil-borne phytopathogenic fungi. RDIPP selected strains of Bacillus amyloliquefaciens, B. licheniformis and B. subtilis provided to be useful in plant protection and formulated them as bioproducts for seed and soil treatments. For pest biological control, entomopathogenic fungi such as Beauveria bassiana, B. brongniartii, Isaria farinosa, Metarhizium anisopliae and Verticillium lecanii are known as efficient. For this reason, the aim of our work was to select compatible microbial strains of biocontrol bacteria and entomopathogenic fungi that could be applied together, as simultaneously treatments, for suppressing diseases and pests attack. Results revealed in vitro compatibility of Bacillus licheniformis 77.1s biocontrol strain with Beauveria spp. entomopathogenic fungi. These biological control microorganisms could be used in combination to prevent in the same time pests and diseases. As a requirement for environmental safety, the selected microbial strains were ecotoxicologicaly tested according to the GLP principles (Good Laboratory Practices) and OECD guidelines. Results proved that the selected strains were nontoxic for non-target species of the aquatic and soil macrofauna: Daphnia magna (crustacean) and Eisenia foetida (earth worm) respectively.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Andreea DOBRE, Iulian GROSU, Alina Elena BUȚU, Călina Petruța CORNEA

Phosphorus is one of the major constituents of which are involved in metabolic processes, nucleic acid and cell membranes biosynthesis as well as in the regulation of a large number of enzymes. Phytate (myo-inositol hexakisphosphate 3-phosphorilase) is the main storage form of phosphorus in various crops (cereals, legumes, and oilseed crops) and its accumulation in natural ecosystems could reduce the availability of various metal ions such as Fe, Zn, Mg or Ca, and could cause environmental pollution effects. Phytases are enzymes that catalyze the hydrolytic phosphate cleavage of phytic acid to lour inositol phosphate esters and inorganic phosphate. In the case of monogastric animals which do not have microbial phytases in their digestive system, the formation of insoluble metal cation-phytate complexes at physiological pH values is regarded as the major reason for poor mineral availability, because these complexes are essentially nonabsorbable from the gastrointestinal tract. However, phosphorus from soil is largely unavailable due to its rapid immobilisation of the organic and inorganic soil constituents. Several studies are focused on the exogenous and endogenous microbial phytases (produced by fungi - Aspergillus niger, Aspergillus ficuum, yeasts - Saccharomyces cerevisiae, or bacteria - Leuconostoc mesenteroides, Bacillus amyloliquefaciens) and their influence in the phytic acid dephosphorylation. The identification and the characterization of new microbial strains able to produce phytase and possible other important compound continue to be of large interest both for fundamental studies and for practical applications. For this reason, the aim of the present work was the identification of new phytase producing microbial strains from soil samples of different origins and by using collection microbial strains. The phytase activity was detected by cultivation on phytase specific medium (PSM) [1.5% glucose, 0.5% (NH4)2SO4, 0.05% KCl, 0.01% MgSO4.7H2O, 0.01% NaCl, 0.01%, CaCl2.2H2O, 0.001% FeSO4, 0.001% MnSO4, pH 6.5 with 0.5% sodium phytate). Six bacteria strains (BPA, OS15, OS17, B4, B5 and B6) and one fungal strains (A.niger An) capable of hydrolyzing sodium phytate were recognized by their surrounding clear halo on PSM containing plates. Preliminary experiments on the characterization of the new isolates were also realized.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Gabriela-Lucica MARGARIT, Diana-Gabriela CONSTANTINESCU-GROPOSILA, Luminita VISAN

Romanian consumers’ concern for food safety and health has increased in recent years due to media news about cases of illness due to the use of improper packaging of various food stuffs. Also, environmental protection actions have contributed to the development of research in the direction of obtaining biodegradable packaging materials but also to educate consumers to use and to promote "eco"packaging concept Our study indicates that the consumer is interested to purchase packaged foods, without incurring increased costs due to the use of a package, to improve the quality of life,and to maintain a good health status. The European Commission indicates to mobilize municipalities towards the achievement of 2020 target 50% recycling to improve waste management and to reduction the amount of disposas.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Gabriela POPA, Mihai Bogdan NICOLCIOIU, Matilda CIUCA, Calina Petruta CORNEA

For long time mushrooms presented interest for consumption as food, as traditional medicine or in bioremediation, due to their nutritional, antioxidant, antimicrobial and therapeutic values. The valorisation of indigenous species of mushrooms both for research or practical applications is a goal for researchers all over the world and requires well characterized collections. Despite the importance of macromycetes, few collections are developed in Europe and they contain mainly standard strains. The existence of extremely rich mycoflora in the forests and grasslands of Romania creates favourable conditions for initiating a scientific approach with definite applicability, in order to diversify the cultivated assortment by introducing of some new indigenous mushroom strains and species. For example, several species from spontaneous mycoflora of Romania have nutritional value or could be used as therapeutic agents: Agaricus campestris, Clytocibe geotropa, Boletus edulis, Hericium coraloides, Pleurotus ostreatus, Armillaria mellea, Flammulina velutipes, Coprinus comatus, Laetiporus sulphureus, Ganoderma applanatum, Ganoderma lucidum etc. Exploitation of such fungal species by introducing into controlled culture may diversify the range of mushrooms for domestic market or for obtaining of innovative products. For this reason the aim of our work was the realization of a fungal germplasm collection based on indigenous isolates obtained from natural ecosystems. 40 mushroom varieties belonging to at least 35 species were isolated and in vitro propagated on MEA or PDA media. The possibility of submerged cultivation of mycelium for some species as well as antimicrobial potential was also examined. Using specific biotechnologies the new mushroom strains included in our collection will be tested for genetic variability and for other important characteristics (producing of enzymes, degradation abilities, antimicrobial and/or antitumor properties etc).

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Petyr PANAYOTOV, Katya YOANIDU, Petya BOYANOVA, Borislav MILENKOV, Kamen DANOV

During the penetrometric study, the efficiency of the method for determining the strain of displacement in rennet gel obtained by chymosin of microbial and camel origin was studied. Using the standard measuring time of 60 s, the monitoring of penetration in the gel for the time of 30 s was also investigated. This approach is applied in defining the strain of displacement from the 10 to 90 min during the formation of the gel. The results obtained by the penetrometric study of the rennet gel are the basis for modification of the method of determination of the strain of displacement. The serum released from the gel during the penetrometric study affects measurement accuracy. The results obtained for 30 s indicate better stability of the experimenal data, which shortening the time for its implementation. The information obtained by the conducted study suggests new modification of the method related to the time of penetration from the 60 to the 30 s.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Petyr PANAYOTOV, Katya YOANIDU, Petya BOYANOVA, Borislav MILENKOV, Dilyana GRADINARSKA

The variation in the rate of formation of rennet gel depending on the use of different types of milk-clotting enzymes for a set time was studied. The intensity of development of the phases for the research process was determinate by the specificity and activity of coagulants. It was found that the strain of displacement was directly related with the time for the gel formation and also with the types of rennet enzymes used for its preparation. The study was conducted with the amounts of rennet enzyme from 10 to 60 cm3 x 10-2 dm-3 and the strain of displacement of the gel changes as values for a period of 90 min. The data obtained from the measuring instrument for the strain of displacement using milk-clotting enzyme with camel origin was in the range of 7,2x.10-6 ÷ 1,3 x 10-5. It was determined that under the similar conditions after 30 min there were no significant changes, these results demonstrate the ability of this enzyme to finalize the process more quickly. Using the enzyme of microbial origin, the values derived for the strain of displacement are θ = 3,4 x 10-6 after 30 min of the experiment and θ = 1,20 x 10-5 at the end of the conducted experiment. The use of this milk coagulant indicates significant changes in the strain of displacement at the initial stage of formation of the gel. It was recorded that differences were reduced as the experiment progresses. The data obtained from the penetrometric study were processed statistically and the results can be apply in laboratory and manufacturing practices using the chymosin of microbial origin and camel chymosin obtained by fermentation.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Krasimira TASHEVA, Georgina KOSTURKOVA

Rhodiola rosea is a medicinal plant, containing a range of antioxidant compounds, including p-tyrosol, organic acids(gallic acid, caffeic acid, and chlorogenic acid), and flavonoids (catechins and proanthocyanidins). The stimulating andadaptogenic properties of Rhodiola rosea are attributed to p-tyrosol, salidroside, rhodioniside, rhodiolin, rosin,rosavin, rosarin, and rosiridin. The recent investigations showed that sucrose influences secondary metabolism in cell,tissue and organogenic cultures. Higher sucrose levels in certain limits lead to increased production of alkaloids in invitro cultures of various plants. The aim of this work was to study the influence of different sucrose concentrations onthe process of callus formation. The nutrient medium containing different percentage of sucrose (20, 30 and 40 %) wereused. Leaves excised from in vitro propagated golden root plants were plated for callus induction and maintenance. Theresults showed that the callogenesis of golden root plants was more effective (2 - 3 folds) when sucrose was 20 g/lcompared to higher concentrations of sucrose at the background of the same combinations of plant growth regulators.The obtained calli differed in structure and color. HPLC analysis of the calli was performed.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Dorica BOTAU, Vanda BOLDA, Sorina POPESCU, Oana BOLDURA

The tissue lines derived from the Arieșeni, Retezat and Valea Sebeșului bilberry genotypes grown on a WPM medium supplemented with 40, 60 and 80 mg/l AS, were subject to molecular analysis through amplification of DNA samples with ISSR and RAPD primers. The results of agarose gel electrophoresis of the amplification products show the existence of significant differences in the model of polymorphic bands obtained from tissue lines, compared to the mother plant. Based on the obtained results, the presence of somatic variability, induced in the tissue lines under the influence of AS, is emphasized. It consists in the absence of binding sites of the HB-12 ISSR marker compared to the mother plant. Considering the statements in the specialty literature, concerning the mutagenic effect of growth, we can state that AS caused changes within the DNA level in the bilberry calluses selected by us under the experimental conditions.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Andreea STAN, Mona Elena POPA

Recently, for increasing smoothies shelf life, food industries used thermal processing, which has been shown in some studies to affect the sensorial and physic-chemical properties of these products. Color, flavor, texture and physico-chemical properties of food products have an important role in correlation with taste, sensory perception and consumer acceptance. These are critical quality attributes affecting the acceptability of fruits, fresh or processed, thus being of major concern in product design. The aim of this study is to observe the influence of chilling storage on color, pH and acidity of some products based on mixtures of pressed and squeezed fruits without adding preservatives or stabilizers. For this purpose, some mixtures of several pressed fruit like apples-pears, peaches-mango and sour cherry –bananas were purchased from a local market. These mixtures were stored in climate chamber at 50C, the color, pH and acidity being analyzed throughout the 27 days chilling storage period. During chilling storage the lightness index, L, yellowness index, b and the redness index, a, were measured and it was observed color changes for all of fruit smoothie samples. pH and acidity values, showed that the fruit smoothie samples registered insignificant changes in this comparative study between the same samples after different chilling storage period.

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