Enzymatic bioprocessing of vegetable oils for the production of biodiesel

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Alexandra GHIORGHIŢĂ, Gheorghe CÂMPEANU, Mircea POPESCU, Florentina ISRAEL, Gabriela NEAŢĂ

Biodiesel is a renewable, alternative fuel for diesel engines, that has captured the attention of the whole world, as it can be used both alone and mixed with diesel for unmodified diesel engines. It is easily obtained from common raw materials, as well as wastes. Biodiesel obtained through biotechnological procedures (biocatalysis) is of superior quality to chemical synthesis biodiesel. The use of purified lipases, such as pig pancreas lipase, Thermomyces lanuginosus lipase or lipase B from Candida antarctica as a biocatalyst for biodiesel obtainment has shown great results and the optimum control parameters have been studied. The production of biodiesel from vegetable oils using different lipases has been investigated. Results have shown that the type of lipase, reaction media and operational parameters (reaction time, temperature, lipase load, alcohol:oil molar ratio and water concentration) have influenced biodiesel yield. In order to establish the best composition and process conditions, an optimization procedure has been carried out. The enzymatic transesterification was performed in an organic solvent-containing system, in agitated flasks, at various temperatures (40-50oC) and for different periods of time (10-14 hours). Also, variations of the alcohol:oil molar ratios, enzyme concentrations and added water percent were studied. A statistic evaluation of the results was performed, for the proper optimization of the process parameters in regard to conversion. Under optimal operating conditions, the fatty acid methyl esters (biodiesel) yields were >90%.

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Ghiorghiţă A. , Câmpeanu G., Popescu M., Israel F., Neaţă G., 2012, Enzymatic bioprocessing of vegetable oils for the production of biodiesel. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 113-118.

 

Evaluating some sensorial, physic-chemical and microbiological characteristics of peas preserved by usual methods

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

In the present study were evaluated some sensorial, physic-chemical and microbiological characteristics of frozen and canned peas, when compared with fresh peas. The sensorial analysis consisted in aspect, aroma and texture evaluation; the physic-chemical parameters analysed were: pH and water activity and the microbiological parameter was total plate count. All samples were purchased from the market, fresh peas in pod, frozen peas packed in plastic bags, in air atmosphere and canned peas packed in glass recipients, in water. 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. Total plate count was evaluated using SR ISO 4833. Results showed that fresh peas had the highest scores for aspect and texture and the most tasteful sample was canned pea. Most acid samples were those of canned peas and most basic ones were those of frozen peas. Water activity registered the highest value for frozen peas and the lowest for fresh peas. Total plate count had the lowest values for canned peas, followed by fresh and frozen peas.

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Dobrea N., Turtoi M., Ghidurus M., 2012, Evaluating some sensorial, physic-chemical and microbiological characteristics of peas preserved by usual methods. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 145-148.

 

In vitro evaluation of the relationships between some fungal pathogens of black currant crop and some saprophytic fungi

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Eugenia PETRESCU, Tatiana-Eugenia ŞESAN, Maria OPREA

Blackcurrant crop is affected by fungal pathogens, such as Mycosphaerella grossulariae, Drepanopeziza ribis (Kleb.)v. Hohn., Alternaria tenuissima (Kunze) Wiltshire, Sphaerotheca mors-uvae (Schw.) Berk, Cronartium ribicola Dietr., Fusarium oxysporum E.F. Sm. Swingle, Botrytis cinerea Pers. In this study has been evaluated the in vitro antagonistic effect of some fungal saprophytic isolates towards some of these phythopathogens in order to establish which of them could be used as biological control agents of black currant crop. In all the cases has been observed the in vitro antagonistic effect of the strain of the fungus Trichoderma spp.

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Petrescu E., Şesan T. E., Oprea M., 2012, In vitro evaluation of the relationships between some fungal pathogens of black currant crop and some saprophytic fungi. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 175-178.

 

Isolation and identification of local wine yeast strains from Dealurile Bujorului vineyard

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Adrian GĂGEANU, Gheorghe CÂMPEANU, Camelia DIGUŢĂ, Florentina MATEI

In the last years it has been given a high importance to promote on the market the Romanian wines with strong indigenous character related mainly to their sensorial profiles (aroma and taste). The wide use of commercial starter cultures, mainly applied to reduce the risk of spoilage and unpredictable changes of wine flavour, can ensure a balanced wine flavour, but it may also cause a loss of characteristic aroma and flavour determinants. This work belongs to a wider project in which, the goal is to demonstrate how the local yeast strains produce volatile compounds and fermentation metabolites which finally will modulate the variety characters on sensorial level. During 2009 -2010, from hundreds of yeast strains isolated from DealurileBujorului vineyard,9 yeast strains have been kept for their fermentative power. Classical and molecular identification of these strains have been performed. The classical identification has followed mainly the oenological practices and classification. The results show that these strains belong to the specie Saccharomyces cerevisiae under different subspecies groups (according to technological classification): S. ellipsoideus, S.bayanus, S.rosei, S.oviformis. By the use of molecular tools (ITS amplification), all the strains belongs undoubtedly to Saccharomyces cerevisiae group, but the instraspecific polymorphism is important. All the strains will be subject of fermentative and flavour development tests on local grapes variety.

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Găgeanu A., Câmpeanu G., Diguţă C., Matei F., 2012, Isolation and identification of local wine yeast strains from Dealurile Bujorului vineyard. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 22-25.

 

New screening methods for evaluation of Fusarium sporulation inhibition by Bacillus biocontrol strains

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Oana-Alina SICUIA, Florin OANCEA, Călina-Petruţa CORNEA

In vitro antagonistic activity of microorganisms is the first approach in the selection of biocontrol microbial strains. The method usually used in this direction is the double culture technique. This method has been improved, in time, in order to be more relevant for the inhibition of some pathogenic growth. However, pathogenic growth reduction is not sufficient in agricultural systems. The vegetative growth inhibition must be complemented by suppression of resistant and/or spreading forms of the pathogens so that the probability of pathogen dissemination will be reduced. Due to these requirements we propose new screening methods to determine the sporulation inhibition, using Fusarium species as a model. Within this study we demonstrated the functionality of these new methods using Bacillus biocontrol strains. The methods are based on the quantification of spores formation, spores dissemination and germination when growing the fungus together with the bacterial biocontrol strains.

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Sicuia O. A., Oancea F., Cornea C. P., 2012, New screening methods for evaluation of Fusarium sporulation inhibition by Bacillus biocontrol strains. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 67-72.

 

Optimisation of culture medium to obtain maximal increase of the extracellular starch degradation activity by the enzymes as products released of the Acidiphilium genus

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Carmen Mădălina CISMASIU

Acidophilic heterotrophic bacteria belonging to the Acidiphilium genus adapted frequently to the environmental concentration of toxic compounds developing protective mechanisms of resistance which are much diversified in those bacteria. The aim of the present paper was the extracellular enzymes production from the acidophilic heterotrophic bacteria belonging to Acidiphilium populations which hydrolysis the starch in the presence of CaCl2 or/and NaCl solutions. These bacterial populations were isolated from acid waters and mine sediments containing high concentrations of heavy metals collected from Baia (Tulcea County) and Roúia Poieni (Alba County). In the culture medium, the optimum of the substrate concentration represented by starch was 0.2 % in the presence of mixed CaCl2-NaCl solutions. The most important physic-chemical parameter that influence extracellular enzymatic activities of the Acidiphilium genus are the contact time between bacterial populations and culture medium with metallic ions solutions. Also, an extended exposure of Acidiphilium populations in the GYE medium with different starch concentrations and 0.1% CaCl2 induce intense starch degradation by extracellular enzymes in acidic conditions.

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Cismasiu C. M., 2012, Optimisation of culture medium to obtain maximal increase of the extracellular starch degradation activity by the enzymes as products released of the Acidiphilium genus. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 103-108.

 

Organic versus conventional food products: physico-chemical and microbiological comparative analysis

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Mihaela DRĂGHICI, Petru NICULIŢĂ, Mihaela GEICU, Alexandra POPA, Denisa DUŢĂ

The importance of organic agriculture has increased in recent years. Therefore, many studies have been done, trying to analyze the differences between organic and conventional food products, especially in terms of chemical composition, microbiological and sensory quality characteristics. Some studies have reported higher values of nutrients in organic foods compared to conventional ones. Development of results is difficult and generalization of findings must be made with great caution. In this respect, the present study meets current requirements in oriented food, free of pollutants and healthy, try aiming to highlight the advantages of organic products. Materials have been used, such as sheep cheese, tomatoes, peppers and cucumbers, to compare the quality of product with its conventional organic one. All samples were analyzed from physico - chemical and microbiological point of view. The results obtained have shown that organic products have a higher degree of safety correlating microbiological, physico -chemical and heavy metal content. Therefore is recommended to increase the production and consumption of organic food.

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Drăghici M., Niculiţă P., Geicu M., Popa A., Duţă D., 2012, Organic versus conventional food products: physico-chemical and microbiological comparative analysis. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 149-155.

 

Preliminary research to develop active packaging for bakery products using essential oils

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Alina A. DOBRE, Petru NICULIŢĂ

In this research the aim was to evaluate the antifungal properties of aromatic plant essential oils in vapour phase, against various fungal strains that causes bakery products alteration. The vapours of clove oil, oregano and white thyme oil were tested against five fungal strains (Aspergillus flavus, Aspergillus oryzae, Aspergillus brasiliensis, Fusarium culmorum, Fusarium graminearum) in a closed system using disc volatilization method which identifies the antifungal potential of essential oil vapours. The results obtained were expressed as minimum inhibitory concentration (MIC) in ppm in a 365.64 cm3 volume Petri dish. Were evaluated nine different concentration of these essential oils (50, 100, 200, 400, 600, 800, 1000, 1500, 2000 ppm) obtained by dilution in a 10% DMSO solution. The best result after seven days of exposure, were shown by oregano oil against all tested fungi with a MIC of 1000 ppm, especially against Fusarium spp., which presented no growth in the area above the disc with oil and no sporulation activity in rest of the Petri dish. Aspergillus ssp. was more resistant to the action of oregano vapours and gives a MIC of 1500 ppm. The vapour phase of clove and white thyme oils were more active at a MIC of 1500 ppm against all fungal strains while at 1000 ppm induced low mycelia growth, influenced the germination of spores which caused immature spores. Vapours of clove oil affected mainly Fusarium spp. by total inhibition of growth in the area of action and in rest affected mycelia development. White thyme oil had a low impact against Aspergillus spp. under study and the most efficient vapours concentration was of 2000 ppm. Main morphological changes observed under light microscopy on fungal strains grown in atmosphere of essential oils were disrupted cell structure, considerable alterations in hyphae, reduced number of conidiospores and loss of pigmentation. In conclusion, tested essential oils were effective in vapour phase leading to important alterations in fungal structure and sporulation process. This work gave us the opportunity to put the base of a protective active atmosphere using essential oils like natural antifungal agents, which could extend the shelf life of packaged bakery products.

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Dobre A. A., Niculiţă P., 2012, Preliminary research to develop active packaging for bakery products using essential oils. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 139-144.

 

Preliminary studies on in vitro behavior of various somatic explants from some cultivated Amaranthus genotypes

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Silvana DĂNĂILĂ GUIDEA, Narcisa BĂBEANU, Ovidiu POPA, Denisa STANCIU, Ioana POPA

The recent renewal of interest in underutilized crops of nutritional and economic potential for the agriculture of the future stimulated the research in Amaranthus sp. cultivation and breeding. In vitro systems have important practical applications not only for rapid breeding of this rediscovered crop but also for producing cell biomass to be used as source of phytochemicals of practical interest. The response of explants from hypocotyl, root and cotyledon node of three varieties of Amaranthus species (Amaranthus cruentus“Amont”, Amaranthus hypochondriacus“Intense Purple”and Amaranthus ssp.”Plenitude”) were recorded, upon their cultivation “in vitro” on media supplemented with different combinations of auxins and cytokinins. Our experimental results pointed out that the explant type, the auxin supplement and the genotype were the most important factors in callus initiation. Calluses were induced most frequently on Murashige&Skoog-MS (1962) basal medium with 0.5 mg/l 2,4-dichlorophenoxyacetic acid (2,4­D),whereas the root development occurred in the presence of NAA 1-2 mg/l(a-naphthaleneacetic acid). Proliferative callus derived from cotyledons and hypocotyls of the studied Amaranthus species were transferred to MS media enriched with hydolyzated casein, NAA and kinetin in order to compare their morphogenetic capacity for plant regeneration.

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Dănăilă Guidea S., Băbeanu N., Popa O., Stanciu D., Popa I., 2012, Preliminary studies on in vitro behavior of various somatic explants from some cultivated Amaranthus genotypes. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 9-14.

 

Preliminary study of lactic acid production from inulin hydrolysates using Lactobacillus acidophilus LA-5

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVI
Written by Octavian BASTON, Camelia NEAGU BONCIU, Gabriela BAHRIM

Lactic acid is widely used in the chemical industry, food industry, cosmetics, and pharmaceuticals. The main objective of the present work was chemical and enzymatic inulin hydrolysis from inulin rich feedstock (dahlia and Jerusalem artichoke) followed by hydrolysates fermentation to lactic acid using Lactobacillus acidophilus LA-5. Chemical hydrolysis of Jerusalem artichoke and dahlia flour was performed with concentrated H2SO4 for one hour at 100°C at different pH of the medium, and the amount of reducing sugars obtained varied between 0.10 to 0.51 g fructose/g dry weight flour for Jerusalem artichoke and between 0.099 to 0.448 g fructose/g dry weight flour for dahlia. The enzymatic hydrolysis was performed by varying the substrate concentration and the pH, and the amount of reducing sugars produced was between 0.439 to 0.56 g fructose/g dry weight flour for Jerusalem artichoke and between 0.435 to 0.522 g fructose/g dry weight flour for dahlia flour. The hydrolyzed substrates were then fermented with a commercial culture of Lactobacillus acidophilus LA-5 for 96 hours. Lactic acid production was monitored and recorded every 24 hours, measuring the pH and total acidity of the samples. The obtained results were then analyzed using Principal Component Analysis. An optimum number of 4 principal components are enough to explain 87.1% of data variation for calibration and 69.8% for validation. PC-1 is given by the acidity evolution, correlated with pH drop during fermentation. The lactic acid accumulation was maximum in the third day of fermentation (after 48 hours) for both dahlia and Jerusalem artichoke.

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Baston O., Neagu Bonciu C., Bahrim G., 2012, Preliminary study of lactic acid production from inulin hydrolysates using Lactobacillus acidophilus LA-5. Scientific Bulletin. Series F. Biotechnologies, Vol. XVI, ISSN-L 2285-1364, 79-85.

 


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