Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Iulia-Roxana ȘTEFAN, Silvia-Simona GROSU-TUDOR, Medana ZAMFIR, Petruța-Călina CORNEA

Production of surface-layer proteins has been described for several species of the genus Lactobacillus. They seem to be responsible for a sum of cell wall functions like protection against physico – chemical agents, adhesion, and aggregation among others. In this study, 15 strains of lactobacilli obtained from different fermented vegetables, cereals, and dairy productswere screened for S-layer production. Five strains were able to produce S-layer proteins, with a molecular mass between 40 and 55 KDa, as shown by sodium dodecyl sulphate polyacrylamide gel electrophoresis .Four of these strains were selected to test the influence of incubation temperature on the bacterial growth and S-layer production. Although the growth at 42°C was slower than at 37°C, similar amounts of S-layer proteins were produced. The proteins were efficiently extracted with 5M LiCl, especially from the cells grown at 42°C.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXII
Written by Arzu KART, Hüseyin ÖZTÜRK

Killer activity is one of the mechanisms of antagonism among yeasts during fermentations. A variety of yeast species secrete a compound which is protein produced outside the cell and is called the killer toxin. Killer toxins are protein in nature and active at low pH. These toxins have a lethal effect against yeasts, bacteria and the moulds, except for their own species. Killer yeasts can be used to prevent the contamination of many spoilage yeasts which are sensitive to killer toxins in food processing via this mechanism during the food fermentations. In this way, it is possible to control of the food spoilage microorganisms and prolongation of the spoilage processes in foods by using of killer yeasts or direct using of killer toxins. The shelf life of foods can be extended by using killer features of yeast, so food resources can be better assessed and economic losses can be prevented. Therefore, it is important to determine the killer yeasts which are effective against spoilage food yeast. For these reasons, it is aimed to determine the effective killer yeast strains against spoiling food yeasts in this study. In the study, yeast isolation was performed to obtain spoilage yeasts from various spoiled fermented foods. At the same time, in this study, the yeasts, which were isolated from different products and obtained from Süleyman Demirel University Food Engineering Department laboratory, were evaluated to determine the killer activities against these spoilage yeasts isolated from various spoilage fermented products. It has been determined that those yeasts, which are effective against sensitive spoilage food yeasts, were investigated by using the agar diffusion method in the solid medium and have a low, medium and high spectrum activities as a result of quantitative experiments. The study was carried out under the 30°C incubation temperature and pH 4 acidic conditions to the determine the killer activity. The results that were obtained in the study were calculated and evaluated over the zone radius. It was determined that the yeasts obtained from laboratory, showed 50% killer activity against spoilage yeasts as a results of quantitative analyses in solid medium. These yeast isolates were classified according to their effect degrees. It was determined that the yeasts obtained from Süleyman Demirel University Department of Food Engineering, showed killer activity against spoilage yeasts isolated from spoilaged food products as a results of in vitro experiments.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Oana-Alina BOIU-SICUIA, Florica CONSTANTINESCU, Călina Petruţa CORNEA

Endophytic bacteria are plant-associated bacteria colonizing the internal plant tissue, living in symbiotic association with their host. Such microorganism could contribute to plant growth promotion and defence against biotic and abiotic stress. Our study aimed to describe new endophytic bacteria from potato tubers. Therefore, a group of 20 endophytic bacteria was isolated from seven Romanian varieties of healthy potato tubers. Four of the isolated strains revealed antifungal activity against three important pathogens of potato, Fusarium solani involved in tubers dry rot, Rhizoctonia solani involved in stem canker and black scurf of potato, and Alternaria solani causing early blight of potato plants. Among all twenty isolates obtained, 13 were Gram positive bacteria. Most of the newly isolated endophytes (65%) expressed phosphatase and protease activity, and 55% presented amylases, however only 10% revealed cellulose degrading enzymes. Based on preliminary laboratory analysis, the isolate 6T4 identified as B. atrophaeus/subtilis revealed promising perspectives for biocontrol strategies.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Ana Valentina ARDELEAN, Marinela CÎRNU, Ioan I. ARDELEAN

In the last forty years there is an increased scientific interest in deeper understanding lipid metabolism in photosynthetic microorganisms, aiming at using the most lipid-rich strains as source for biodiesel production. One of the many constraints is the selection of strains with high lipid content. This paper presents the isolation, purification and selection of three strains of photosynthetic microorganisms by using an already known method, iodine vapour method, (Work et al., 2010) which allows to rapidly and easily select those colonies which low starch content as potential high lipid- containing isolates. These results show that in the three selected strains, the fluorescence emission after Nile red addition is increased with different values: 7.597; 10.832 and 11.428 for strains 9.3.1, 9.8.2 and 12.9.0, respectivley.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Svetlana COLCERU-MIHUL, Corina BUBUEANU, Ecaterina Anca ŞERBAN, Alice GRIGORE, Domnica RUGHINIS, Cristina BAZDOACĂ, Sultana NIŢĂ

The aim of these studies was to obtain Rosmarini folium selective fractions with beneficial effect in counteracting diseases associated with aging processes. By four different methods 9 selective fractions were obtained. HPLC analysis and quantitative determination of active principles from selective fraction show that the values obtained from individual assessment by HPLC were well correlated with the values obtained by the spectrophotometrically methods. The selective fractions have a total flavonoid content expressed as rutin from 2.004 to 66.970% and respectively 0.651 to 10.284% polyphenolcarboxylic acids expressed as rosmarinic acid. Antioxidant activity evaluation showed that polyphenolcarboxylic acids rich fractions such as RIII: 10.284%, RIIC: 10.257%; had 89.44%; 88.12% antioxidant activity in 1% dilution and 87.52%; 89.07% antioxidant activity in 0.1% dilution, similar to rosmarinic acid who has antioxidant activity of 88.99% respectively 89.84% in dilution of 1% respectively 0.1%. The fractions with 2.642% - 3.950% polyphenolcarboxylic acid content exhibited an antioxidant activity of 45.73% - 87.5% in 1% dilution and of 8.75 to 87.500% activity in 0.1% dilution. Comparing the antioxidant activity of selective fractions and the polyphenolcarboxylic acids content expressed as rosmarinic acid it can be concluded that when the concentration of polyphenolcarboxylic acids increases the antioxidant activity also increases, though not an exact correlation can be made. A correlation between the flavones content of the selective fractions and antioxidant activity can not be made by this method.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Svetlana COLCERU-MIHUL, Sultana NITA, Alice GRIGORE, Corina BUBUEANU, Elena DRAGHICI, Emanuel VAMANU, Domnica RUGHINIS

It is known that oxidative stress and inflammation play an important role in the onset of arterial disorders, very common in the elderly. Cynara scolymus L. is one of the best recommended species for prevention and control of diseases associated with aging processes, mostly due to its high polyphenol content - luteolin, luteolin-7-glucoside, caffeic acid, chlorogenic acid. The aim of the study was to obtain some selective fractions from Cynara scolymus L. leaves with various contents of caffeic, chlorogenic and rosmarinic acids, cynarin, luteolin-7-glucoside, apigenin-7-glucoside and rutin determined by HPLC and to establish the relationship between concentration and antioxidant activity. Eight selective fractions obtained by two distinct methods containing 0-0122% caffeic acid, 0-0.443% rosmarinic acid, 0.007-1.504% chlorogenic acid, 0-0.097% cynarin, 0.054-1.6662% luteolin-7-glucoside, 0.009-1.366% apigenin-7-glucoside and 0-0.396% rutin exhibited antioxidant activity at 0.001, 0.01, 0.1 and 1% dilution, varying from 0.27 to 87.77%. More precisely, selective fraction C6 containing 16.662% luteolin-7-glucoside and C8 selective fraction containing 5.568% luteolin-7-glucoside and 1.504% chlorogenic acid exhibited 87.77%, respectively 84.44% antioxidant activity at 1% dilution and 85.27%, respectively 69.44%. antioxidant activity at 0,1% dilution. The reference substance luteolin-7-glucoside showed 87.16% antioxidant activity at 1% concentration and 85.56% at 0.1% concentration. All selective fractions exhibited antioxidant activity and the action was correlated with their active substances concentration.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Elena UTOIU, Anca OANCEA, Alexandra GASPAR, Ana-Maria SECIU, Laura M. ȘTEFAN, Viorica COROIU, Oana CRĂCIUNESCU, Cristinel Dumitru BADIU, Florin OANCEA,

Cruciferous vegetables are known as food with chemopreventive effect due to their high content in bioactive compounds, such as mineral nutrients, including selenium, antioxidants, vitamins and glucosinolates, which were shown to inhibit cancer cell growth, both in vitro and in vivo testing. The aim of this study was to evaluate the effect of a new selenium-based composition, applied on experimental field conditions to cauliflower plants (Brassica oleracea L.), on their chemopreventive compounds level and antitumoral activity. Treated plants, cultivated both in normal watered and water stress conditions, were compared for total selenium and sulforaphane contents, determined by electrothermal atomic absorption spectrometry (ETAAS) and high performance liquid chromatography (HPLC), respectively. In vitro cytotoxicity of cauliflower extracts was evaluated in NCTC fibroblast cell line, while their antitumoral activity was tested in Caco-2 human adenocarcinoma cell line using MTT colorimetric assay. The results indicated that the applied biofortification treatments increased the selenium intake, allowed formation of bioactive glucosinolates and enhanced the antitumoral activity of cauliflower plants cultivated in both normal watering and water stressed conditions. In conclusion, this new biotechnological approach on cauliflower cultivation, using a treatment with a novel selenium-based composition, could be considered promising step for obtaining functional food from cauliflower crops.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Mirela C. IORDAN, Ioan I. ARDELEAN

This paper presents the short term (5 hours) evolution of ammonium, nitrite, nitrate, total phosphorus and COD of a synthetic wastewater treated in a laboratory activated sludge sequencing batch reactor. In the experiment with 4.33 g/L activated sludge and the initial raport COD:N:P of 154:5.3:1 in about 4 hours 31% of COD and 83% of ammonium were removed, whereas nitrate shows an increase of 89%. In the experiment with 4.71 g/L activated sludge and the initial raport COD:N:P of 195:3.22:1 in about 4.5 hours 26% of COD and 92% of ammonium were removed, whereas nitrate shows an increase of 85%. In the experiment with 4.34 g/L activated sludge and the initial raport COD:N:P of 103:4.45:1 in about 4.5 hours 30% of COD and 48% of ammonium were removed, whereas nitrate shows an increase of 65%.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Anat DENYINGYHOT, Chirapiphat PHRAEPHAISARN, Mongkol VESARATCHAVEST, Winai DAHLAN, Suwimon KEERATIPIBUL

Halal food approved for Muslim consumers is strictly noticed that avoiding from contaminations that do contradict from Islamic regulations, such as the contamination of animal forbidden by Halal standards. Importantly, High resolution melting analysis (HRMA) is a potential molecular technique, which is used for identifying the species of organisms. Therefore, the research objective is to use the HRMA technique for simultaneous detection of the three forbidden animals (pigs, dogs, and rats) that have high opportunity to be adulterated in Halal food. The HRMA, targeting a fragment of NADH dehydrogenase (ND5), ATPase subunit 6 (ATP6), and Cytochrome B (Cytb) genes, were developed in order to authenticate the forbidden animal and their mixtures. Species-specific primers were designed and combined in a multiplex HRMA resulting in different sequences and therefore different melting behaviours for each species. The multiplex HRMA was then evaluated the PCR specificity against the targeted DNAs of targeted and nontargeted. It’s demonstrated that the method had no cross-reaction with DNA from the experimental animal species (pigs, dogs, rats, cats, monkeys, chickens, horses, sheep, goats, and donkeys). The HRMA profile of amplified amplicons from the targeted animals produced uniquely melting peaks that were easily distinguished for each species in this study. Taken together, all data indicates that this multiplex HRMA is a simple, fast, specific, and cost-effective detection method for pig, dog, and rat in halal food. In order to carry out the analysis of commercial food products, 150 commercial food products was used to screen by species-specific primers for pigs, dogs, and rat were combined in multiplex HRMA. This method revealed that one sample was contaminated with pigs’ DNA in the examined products. Therefore, the HRMA could be used as a halal verification technique for detecting aforementioned forbidden animals contaminated in halal food products.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Selda BULCA

Carob (Ceratonia silliqua) is an evergreen, drought resistant tree. It has a good nutritional value, a long shelf-life (2-3 years) and it is relatively cheap. Due to its high sugar content, carob is naturally sweet. This property makes it usefulin, as an antioxidant in different foods, as a thickener, stabilizer or flavourant in food applications, in ethanol, lactic acid production, in medical applications, in cosmetic emulsionsetc. In food research, new product development of carob could contribute greatly to the promotion of carob as a food source and hence towards its commercial value. Carob’s application in the food industry is mainly focused on the extraction of carob bean gum (locust bean gum). The use of the deseeded pod in food is, however, minimal and thus carob’s economical market value is low. The current world production of carob extracts is estimated at 315000 tons per year, with Spain being the main producer and exporter (42%) and followed by Turkey with 5% in the Mediterranean and Aegean region. This review is focused mainly on the properties of carob tree, chemical composition, human and animal nutrition, medical applications, health benefits, polyphenol content, and antioxidant properties of carob pod and the use of carob pod in different areas.

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