PRELIMINARY STUDIES ON YEAST-PLANT SYSTEMS WITH APPLICATIONS IN PHYTOREMEDIATION

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Ortansa CSUTAK, Alexandra SIMON-GRUIŢĂ, Viorica CORBU, Nicoleta CONSTANTIN, Daniela POJOGA, Tatiana VASSU, Georgiana DUŢĂ-CORNESCU

Phytoremediation represents an ecological and economic alternative for remediation of polluted environments. The combination of plants and xenodegrading microorganisms is often used for the improvement of the remediation process. Yeast strains Yarrowia lipolytica CMGB32, Cryptococcus curvatus YR-P2 and Rhodotorula glutinis RG5 were tested for assimilation of petroleum and n-hexadecane and biosurfactant synthesis. Y. lipolytica CMGB32 grew well on n-hexadecane over two weeks, C. curvatus YR-P2 degraded petroleum during the first ten days, while R. glutinis RG5 was more active at the beginning of incubation period. All strains produced good rates of biosurfactants. Bean (Phaseolus vulgaris) seeds were sown in pots with sterilized soil and a mixture of the three yeast strains in the presence of petroleum and n-hexadecane (2:1 v:v) and observed for a month. Similar experiments were performed using oil polluted soil from oil wells (Ploiesti area, Romania) and a mixture of polluted soil, sand and gravel. The plants grew slowly on sterilized soil, with visible results only after three weeks. The presence of oil well polluted soil allowed seed germination during the first week due probably to complex interaction between soil native microorganisms-yeast mixture-plant-pollutant which provided the necessary nutrients. Although P. vulgaris has the ability to convert contaminants in less toxic compounds and to fix atmospheric nitrogen, the yeast mixture seems to enhance the plant growth, fully developed plants being observed after two weeks compared to control plants. Soil aeration was also a determinant factor, since seeds planted in soil mixture showed the most rapid growth during first week. The results suggest a positive influence over long period of time of the yeast mixture on plant growth in presence of oil compounds. Further work aims optimization of the novel yeast-plant system as basis for phytoremediation studies.

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CSUTAK O., SIMON-GRUIŢĂ A., CORBU V., CONSTANTIN N., POJOGA D., VASSU T., DUŢĂ-CORNESCU G. 2017, PRELIMINARY STUDIES ON YEAST-PLANT SYSTEMS WITH APPLICATIONS IN PHYTOREMEDIATION. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 183-189.

PRODUCTION AND OPTIMIZATION OF EXTRACELLULAR AMYLASE FROM A NEWLY ISOLATED STRAIN OF Bacillus mycoides

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Caterina TOMULESCU, Mişu MOSCOVICI, Bujor ALBU, Roxana STOICA, Claudia SEVCENCO, Delia JITEA, Radu TAMAIAN, Adrian VAMANU

Microbial enzymes are known to be superior to enzymes obtained from other organisms, particularly for applications in industries on commercial scales. The species of the genus Bacillus are known to be producers of enzymes of industrial interest. Among them, amylolytic enzymes have got great biotechnological applications and economic exploitations. Amylases are known to be produced by a variety of bacteria and fungi and their applications at industrial level have stimulated interest to explore their amylolytic activity in several microbes to be used as bioresources. A newly soil-isolate, identified as a Bacillus mycoides strain, was tested for its ability to produce extracellular amylase in liquid media, using multiple carbon sources and starchy substrates. Chip electrophoresis was used to obtain the electrophoretic profile of proteins derived from the bacterial isolate and a molecular weight of 60 kDa, characteristic for amylase produced by Bacillus genus, was obtained in two experimental media. Bioprocess optimization was designed using L9 and L16 Taguchi orthogonal arrays and analyzed by ANOVA statistical methods. A maximum enzymatic activity (10.44 U/ml) was determined when malt extract and ammonium sulphate, as starchy substrate and nitrogen source, were used. Optimum growth conditions were identified to be 32°C, 220 rpm and 48 hrs fermentation time, while the inoculation volume was 2%. A positive effect for amylase production was observed for citric acid and CaCl2 interaction in the culture media.

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TOMULESCU C., MOSCOVICI M., ALBU B., STOICA R., SEVCENCO C., JITEA D., TAMAIAN R., VAMANU A. 2017, PRODUCTION AND OPTIMIZATION OF EXTRACELLULAR AMYLASE FROM A NEWLY ISOLATED STRAIN OF Bacillus mycoides. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 239-248.

RESEARCHES CONCERNING THE ENZYMATIC ACTION OF BYPRODUCT GRAPES

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Mihaela DUMITRU, Ștefana JURCOANE

The objective of the present research was to convert the grape pomace as energy source, by controlling to increase hydrolysis of the complex sugars (celluloses, hemicelluloses) to fermentable sugars. Hydrolysis can be performed chemically or enzymatically following the appropriate pretreatment steps. The chemical pretreatment of the grape pomace substrat present many disadvantages such as the high costs, the special conditions and the formation of toxic by-products. For this reason, we used hydrolysis enzymatic process, as the most efficient method. The efficiency a commercial enzymatic product - MethaPlus L 100 (containing β-glucanase, cellulase, xylanase) was investigated to hydrolyse dry grape pomace, after physical pretreatment (ground 1mm sieve diameter) to fermentable sugar. The enzyme MethaPlus L 100 was added in different concentrations 0.1 – 1 % (w/w) referred to the substrate dry matter content. The reducing sugars concentration increased of 4.0 fold (when 0.01% MethaPlus L 100 was added) reported relatively to the untreated sample. However, an increase of enzymes concentrations not economically relevant. In the future, the efforts should be focused on the improving the enzymatic treatment of the grape pomace, to be used as nutritional component in animal feed.

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DUMITRU M., JURCOANE S. 2017, RESEARCHES CONCERNING THE ENZYMATIC ACTION OF BYPRODUCT GRAPES. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 206-209.

SALT TOLERANCE OF BACTERIAL STRAINS ISOLATED FROM HYPERSALINE WATER LOCATED IN LOPATARI, ROMANIA

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Irinel Gabriel PROCA, Florentina MATEI, Camelia Filofteia DIGUȚĂ, Ștefana JURCOANE

Saline waters are environments largely unexplored in which organisms are able to survive/withstand in the extreme conditions. The aim of this research was to explore saline water located in Lopătari, Buzău County, România. Several physico-chemical properties were assessed such as pH, density, concentration of cations and anions. The pH of water sample was slightly acidic (5.2).The ions of sodium, chloride and total dissolved solids were detected dominant 129.9 g.L-1, 209.83 g.L-1 and 113 gL-1, respectively. A total of fourty four (44) aerobic bacteria were isolated on culture media supplemented with 5%, 10 %, and 15% NaCl, respectively. The isolates were screened by morphological criteria, Gram stain. All bacterial isolates were tested for their tolerance to different concentrations of salt in solid media. Two bacterial isolates (4.5%) has grown over a wide range of salt concentrations ranging from 0% to 12.5%, 17 bacterial isolates (38.6%) under salt concentration between 0% and 7.5%. Other 19 bacterial isolates (41%) demonstrated a large salt tolerance ranging from 5 to 25%. Halophiles can offer important opportunities in biotechnological applications such as food, pharmaceutical, detergents, environmental bioremediation and biosynthetic processes, being one of the main reasons for the future research of them.

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PROCA I.G., MATEI F., DIGUȚĂ C.F., JURCOANE S. 2017, SALT TOLERANCE OF BACTERIAL STRAINS ISOLATED FROM HYPERSALINE WATER LOCATED IN LOPATARI, ROMANIA. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 229-232.

SATISFACTION LEVEL OF STUDYING THROUGH E-LEARNING SYSTEM AT THE STUDENTS ENROLLED IN THE BIOTECHNOLOGY EDUCATION

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Gabriela MARGARIT, Radu Cristian TOMA, Diana GROPOSILA, Dana BARBA

A lot of studies about online education are meant to answer about how efficient is this new way of a learning system, or how interested are students to learn using online platform, choosing themselves when or where to study without a program which requires their simultaneous presence in the same place and at the same time. In 1999, American Teachers Federation and National Association for Education initiate a research about distance learning efficiency. From that year till now, many researchers or teachers have been interested in how good is the e-learning system, the feedback from students being anytime important.

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MARGARIT G., TOMA R.C., GROPOSILA D., BARBA D. 2016, SATISFACTION LEVEL OF STUDYING THROUGH E-LEARNING SYSTEM AT THE STUDENTS ENROLLED IN THE BIOTECHNOLOGY EDUCATION. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 358-361.

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SCREENING FOR S-LAYER PRODUCTION BY SOME LACTOBACILLI FROM HOME-MADE FERMENTED FOODS

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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ȘTEFAN I.R., GROSU-TUDOR S.S., ZAMFIR M., CORNEA C.P. 2016, SCREENING FOR S-LAYER PRODUCTION BY SOME LACTOBACILLI FROM HOME-MADE FERMENTED FOODS. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 167-171.

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SELECTION AND CHARACTERIZATION OF NEW ENDOPHYTIC BACTERIAL STRAINS ISOLATED FROM POTATO TUBER USEFUL IN BIOCONTROL STRATEGIES

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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BOIU-SICUIA O.A., CONSTANTINESCU F., CORNEA C.P. 2017, SELECTION AND CHARACTERIZATION OF NEW ENDOPHYTIC BACTERIAL STRAINS ISOLATED FROM POTATO TUBER USEFUL IN BIOCONTROL STRATEGIES. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 23-28.

SELECTION OF MICROALGAL STRAINS WITH LOW STARCH CONTENT AS POTENTIAL HIGH LIPID - CONTAINING ISOLATES

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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ARDELEAN A.V., CÎRNU M., ARDELEAN I.I. 2017, SELECTION OF MICROALGAL STRAINS WITH LOW STARCH CONTENT AS POTENTIAL HIGH LIPID - CONTAINING ISOLATES. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 210-215.

SELECTIVE FRACTIONS OBTAINED FROM PLANT SPECIES CULTIVATED IN ROMANIA WITH POTENTIAL EFFECT ON COUNTERACTING DISEASES ASSOCIATED WITH AGING PROCESSES

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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COLCERU-MIHUL S., BUBUEANU C., ŞERBAN E.A., GRIGORE A., RUGHINIS D., BAZDOACĂ C., NIŢĂ S. 2017, SELECTIVE FRACTIONS OBTAINED FROM PLANT SPECIES CULTIVATED IN ROMANIA WITH POTENTIAL EFFECT ON COUNTERACTING DISEASES ASSOCIATED WITH AGING PROCESSES. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 325-329.

SELECTIVE FRACTIONS WITH ANTIOXIDANT ACTIVITY FROM ROMANIAN CULTIVATED CYNARA SCOLYMUS L.

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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COLCERU-MIHUL S., NITA S., GRIGORE A., BUBUEANU C., DRAGHICI E., VAMANU E., RUGHINIS D. 2016, SELECTIVE FRACTIONS WITH ANTIOXIDANT ACTIVITY FROM ROMANIAN CULTIVATED CYNARA SCOLYMUS L.. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 347-351.

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