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 Diana GROPOȘILĂ-CONSTANTINESCU, Ovidiu POPA, Narcisa BĂBEANU, Gabriela MĂRGĂRIT, Andreea ÎNSURĂȚELU

Today attention is given increasingly higher to plants, considering that they represent an inexhaustible source of raw materials that regenerates every year. Plants can be used as raw materials in the preparation of drugs or in industrial extraction of active principles. The advantage of phytotherapy is that plant based drugs have a positive impact not only on a single organ or a specific system, but on the whole body. Experimental research focused on the following plant materials: sea buckthorn (Hippophae rhamnoides), hawthorn leaves and flowers (Crataegus oxyacantha), garlic bulbs (Allium sativum) and maple buds (Acer campestre). They were tested in order to characterize, identify and determine the content of active compounds. The analysis of the extracts revealed a high content of lipase in sea buckthorn, 6,3 U/g, as well as in garlic, 4,9 U/g, while the buds maple had a very low lipolytic activity, only 0,4 U/g. The highest content of flavones was determined in leaves and flowers of hawthorn and sea buckthorn. Reducing compounds were determined in large quantities in sea buckthorn, while the other materials tested showed a 50% lower content. The highest content of polyhydroxyphenols was determined in hawthorn and sea buckthorn. Sea buckthorn was also noted by a very high content of vitamin C, 483 mg/100 g. The results obtained in these experiments allowed the selection of plant products rich in many active principles involved in the regulation of lipid metabolism.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Radka VLASEVA, Mihaela IVANOVA, Nadezhda PETKOVA, Mina TODOROVA, Panteley DENEV

The production of functional lactic acid dairy products constantly increases nowadays. They are usually used to enrich with soluble dietary fibers that enhance their functional characteristics. The aim of the current research was to investigate the lactic acid dairy products enriched with inulin-type fructans with different degree of polymerization and to analyse the fructooligosacharides and inulin content in them after lactic acid fermentation. For the yoghurt preparation inulin and fructooligosacharides extracted from tubers of Helianthus tuberosus L. and commercially available inulin from chicory were used. The amount of fructans from inulin-type was determined by spectrophotometric, TLC and HPLC-RID methods. The results from the analysis showed that after lactic acid fermentation the content of inulin changed in a very small amount and the obtained product possessed improved healthy and potential prebiotic effect.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Oana-Alina SICUIA, Florentina ISRAEL-ROMING, Oana CIOBOTARIU, Adrian MATEI, Medana ZAMFIR, Matilda CIUCĂ, Călina Petruța CORNEA

The contamination of food and feed by mycotoxigenic fungi that belong to genera Aspergillus, Alternaria, Fusarium and Penicillium poses significant risks for animal and human health. The mycotoxins (aflatoxins, trichothecenes, ochratoxins, fumonisin etc) produced by such spoilage fungi can be carcinogenic, hepatotoxic, teratogenic or immunosuppressing (Logrieco et al., 2003; Atanda et al., 2013). The limitation of the mycotoxin contamination of food and feed could be achieved by specific methods that inhibit the fungal growth. Several approaches are described by now to avoid the accumulation of mycotoxins, directed towards: prevention of contamination; decontamination of mycotoxin-containing food and feed; and inhibition or absorption of mycotoxin content of consumed food into the digestive tract (Juodeikiene et al., 2012). The use of biological control microorganisms (bacteria, yeasts or fungi) to inhibit the growth of mycotoxin producing fungi and/or degrade the mycotoxins is an important strategy for prevention/decontamination of products (Tsitsigiannis et al., 2012). The aim of this work was the screening of new lactic acid bacteria (LAB) strains isolated from plant materials or some Romanian traditional foods for antifungal action againstplant pathogenic fungi and mycotoxin producing Aspergillus strains. 123 strains of LAB were examined for anti-Aspergillus action and 24 out of them (more than 21%) exhibit strong inhibitory activity against the growth of A.flavus, A.ochraceus and A.niger strains after 3 days of incubation. For most of the LAB strains the inhibitory action was maintained even after 14 days of incubation. The principal antifungal compound is represented by lactic acid, quantified by HPLC. Important damages of the fungal hyphae were observed at microscopic level (fragmentation, loss of the cellular content, twisting of hyphae or apical swelling). 17 new isolate of Aspergillus spp. were obtained and their ability to produce mycotoxin was evaluated by qualitative and quantitative methods. Four of them were used for interactions with LAB: strong and stable inhibition was obtained with the LAB strains designated as 35, 58 and 26. The results suggest that selected LAB could be used for fungal growth inhibition and possible for mycotoxin content reduction.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Steliana RODINO, Marian BUTU, Petruta PETRACHE, Alina BUTU, Calina Petruta CORNEA

Natural fungicides are gaining increased attention because of their environmentally friendly properties, being easily accessible and relatively cost effective, in the perspective of sustainable methods of plant disease control The aim of the present work was the investigation of the in vitro antifungal activity of the ethanolic and aqueous extracts obtained from four locally available traditional medicinal plants from Romania, collected from different regions of Southern part of the country. The four plants taken into consideration were absinth (Artemisia absinthium), rosemary (Rosmarinus officinalis), jimson weed (Datura stramonium) and cocklebur (Xanthium strumarium), and their antifungal properties were tested against the plant pathogenic fungus Alternaria alternata. All extracts obtained from the selected plants presented antifungal potential, demonstrated by the inhibition of the mycelial growth. Generally, the ethanolic extracts showed a higher antifungal activity than the aqueous extracts, for all the tested variants. The results of this study confirm that the ethanolic and aqueous extracts of the selected plants can be used as an alternative in control of the tested phytopathogenic fungus.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Adrian MATEI, Călina Petruța CORNEA

Lactic acid bacteria have been considered to be promising natural biological antagonists for mycotoxigenic fungi that contaminate various food commodities. Apart from important economic losses, mycotoxin producing fungi have harmful effects on human and animal health. The public necessity for high quality food, without addition of chemical preservatives, with extended shelf life, determined the search of new strains of bacteria able to produce lactic acid and their use to control the fungal growth of plant pathogenic and mycotoxigenic species. The effect of 27 strains of lactic acid bacteria have been assayed on the growth of Alternaria solani plant pathogenic fungi isolated from heavily infected tomatoes as well as on potential mycotoxin producing fungi Aspergillus ochraceus isolated from tomato roots grown in greenhouse and Penicillium digitatum isolated from infected oranges. Interaction between lactic acid bacteria and selected mycotoxigenic fungi was tested by overlay assay method. Discrete spots of liquid cultures of tested lactic acid bacterial strains were placed on MRS agar and after incubation, overlaid with soft PDA containing propagules of tested fungi. Data were collected after 48 hours concerning the diameters of clear visible inhibition zones of fungal growth around the lactic acid bacterial strain spots. Preliminary tests have shown that selected lactic acid bacteria could inhibit the development of test fungi. A number of 11 lactic acid bacterial strains have shown antifungal activity on both Aspergillus ochraceus and Penicillium digitatum. Another 5 strains of lactic acid bacteria did not inhibit any of the two mycotoxigenic fungal species. The effect of lactic acid bacteria on plant pathogenic species Alternaria solani did not provide conclusive results and need further study. The results could be used in future experiments for obtaining performing biological agents with application in food safety.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Jordanka ALEXIEVA, Dasha MIHAYLOVA, Aneta POPOVA

The radical scavenging capacity of 70 % ethanol extracts obtained from Allium ursinum L. and Allium bulgaricum L.was investigated in the present paper. The antioxidant capacity of the extracts was estimated with the use of ABTS,DPPH, FRAP, and CUPRAC assays and the total phenolic content was evaluated as well. The Allium bulgaricumextract appeared to possess a better antioxidant activity compared to the Allium ursinum extract, which was inaccordance with the established higher content of total polyphenols for A. bulgaricum extract was 0.41 ± 0.09 mgGAE/g fresh plant weight. In comparison the polyphenols in the A. ursinum extract were found to be 0.40 ± 0.03 mgGAE/g fresh plant weight. The conducted simple TLC method for rapid determination of allicin and alliin in Allium spp.suggested a presence of those substances in both extracts considering the distinctive spots.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Florentina ISRAEL-ROMING, Petruța CORNEA, Evelina GHERGHINA, Gabriela LUȚĂ, Daniela BĂLAN

Biodegradation of fibrous protein is a challenge due to the resistance of the raw material. Enzymes based processes are an alternative to conventional chemical ones because they are environmental friendly, but their efficiency is still limited. They are used mainly in the process of leather obtaining. In the last decade they gain a lot of credit for waste degradation purposes. The main enzymes involved in leather and fur degradation are collagenases and keratinases. The aim of the reported researches is to test a proteolytic complex for its capacity of destroying leather and fur wastes. Four bacterial strains were tested regarding their capacity of hydrolyzing collagen and keratin from bovine leather and sheep fur. For comparison synthetic fur was considered too. Best results were obtained when using sheep leather. The influence of leather dyes was also investigated. Three types of sheep fur were tested: no painted, white painted and black painted. For the painted materials the degradation was less than half, especially when assessing collagenases activity.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Dumitru VÂJU, Grigore VLAD, Mihaela HETVARY, Gabriela BAISAN, Sorin Claudiu ULINICI

The paper presents a case study, for the drinking water plants which involve a bio-filtration step used to reduce simultaneously, certain pollutants (iron, manganese, ammonia) in a single stage filtration. The bio-filtration step, with microorganisms multimedia doped layers was compared with a classic filtration step. The new approach shows the advantage of: higher yields of water pollutants reduction at low specific energy consumption. The bio-filtration process is preceded by an electrochemical pre-treatment whose role is: oxidation of dissolved substances from water, turn non biodegradable organic substances in biodegradable, favour coagulation and flocculation processes, bio-filtration process improvement. In order to optimize the process, was developed and validated a mathematical model of biofiltration process.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Mihail MAGHER, Natalia LEMANOVA, Maria MAGHER

Crown gall is a widespread disease of cultivated culture all over the world. The bacterial pathogen Agrobacterium tumefacience colonize the xylem vessels of the plants.The tumors form in stems and roots of fruits culture. Large tumoursmay death of new plants in the nursery and in the plantation. Tumouregenesis causing root decay may be factor involved in the complex syndrome. Development of measures to controle crown-gall is carried out in direction for obtaining tumorless plants at the expens of preventive treatment of woundings so as to deteriorate the interaction of pathogen with the cell of host plant. Utilization the strain of soil inhibiting Pseudomonas fluorescens CR- 330 D which synthesize the substances (bacteriocins) with preventing activity to nopaline and octopine strains of pathogenic agrobacteria. Liquid concentrate suspension of this bacteria - biological preparat < Paurin> -were applicated for preplanting treatment of rooted saplings. Using to treat apple MM-106 wilding prior to planting into fruit nursery allowed to decreases the outcome of apple saplings affected by crown gall down to 2 – 2.5 %. He is capable to compete with soil microflora and get reliably fixed in rhisosphere without phytotoxicity, which is rather advantageous for using biological control against repeated inoculation with crown gall pathogen.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVIII
Written by Katya VELICHKOVA, Ivaylo SIRAKOV, Stefka STOYANOVA

Algae are sustainable sources of biomass for fuel, food, feed and essential for their growth are light, CO2, andinorganic nutrients like nitrogen and phosphorous. The aim of our study was to explore the effect of different carbonsources on biomass accumulation in microalgae Chlorella vulgaris and its ability to remove N and P compoundsduring its cultivation in aquaculture wastewater. Microalgae cultivation was initiated in bioreactor from 500ml Erlenmeyer flask containing 250ml wastewater from semi closed recirculation aquaculture system. The cultures weremaintained at room temperature (25-27ºC) on a fluorescent light with a light:dark photoperiod of 12 h: 12 h. Themicroalgae were cultivated in wastewater with two different carbon sources: carbon dioxide (2%, v/v), and sodiumbicarbonate (NaHCO3) (1.125g.l-1). The growth of strain was checked for 96 hours period. In our study C. vulgarisshowed better growth in wastewater from aquaculture with bicarbonate utilization as carbon source during the experiment.

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