Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Georgeta FIDLER, Gabriela POPA, Alina BUTU, Steliana RODINO, Calina Petruta CORNEA

Laetiporus sulphureus (Bull. Fr.) Murill., is a wood-rotting basidiomycete mushroom well known for it nutritional value. In this study, alcoholic and aqueous extracts obtained from a Romanian isolate of L. sulphureus cultivated on various culture media were investigated for the antimicrobial operties. PDA, malt extract as solid media and PD (I),malt extract (II), YPG (III) and Hwang (2008)(IV) -as liquid media were used for in vitro cultivation of L. sulphureus,in order to evaluate the optimal medium for an efficient biomass production of L. sulphureus. Between all media tested,best results regarding the growth of mycelia, were obtained when I, II, IV media were used. Only on IV (Hwang)culture medium was observed the typically orange pigment aborated by fungus. Alcoholic and aqueous extracts of fruit bodie and submerged mycelium developed in liquid media were analyzed against strains of Candida albicans ATCC10321, Candida parapsilopsis CBS604, Escherichia coli, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas fluorescens and Pseudomonas aeruginosa. The results shown that the types of culture media for biomass production of L. sulphureus and their aqueous and alcoholic extracts tested against these pathogens have different effects on inhibitory activity. Between the two types of extracts tested aqueous extracts were inferior to alcohol extract in their inhibitory activity on all organisms except Candida sp. in interaction with L. sulphureus aqueous extract from biomass developed on IV medium.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Emanuel VAMANU, Adrian VAMANU, Elena DOPCEA

Several commercial varieties of tinctures were analyzed for determining their antioxidant potential, since most knowledge relating to therapeutic properties of medicines are obtained from folk phytomedicine. Antioxidant potential was determined by the scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radicals, reducing power, and chelating activity. The best results against scavenging of free radicals were obtained with tincture from Vaccinium vitis-idaea,followed by Capsicum annuum and Melissa officinalis. There were obvious significant differences between the free radicals’ scavenging activities. Results were correlated with values obtained for reducing power and chelating ability. This finding was also confirmed by the low values of the EC50. Also, the results were positively high when correlated with total phenolic and flavonoidic contents from the tinctures. The results given herein are the scientific proof that confirms the empirical medical knowledge on how to use the three tinctures in oxidative dysfunctions.

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

In the last years degradation of aromatic compounds by white-rot fungi has been intensively studied. Several studies revealed the abilities of the white-rot fungus Pleurotus ostreatus to degrade a variety of polycyclic aromatic hydrocarbons in liquid culture as well as in a semi-natural substrate. In the present study, two isolates of P. ostreatus (P50, P421) and a sample of P. ostreatus collected from Chitila woods were evaluated for their ability to use crude-oil as a source of carbon. The P. ostreatus samples were inoculated in plates with crude oil (1ml) spread on the entire carbon free mineral salt medium (MSM) surface and in plates with pieces of filter paper soaked in crude oil and placed around the inoculum. Two weeks after, the culture media were completely covered by mycelium. These results indicated that both isolates of P. ostreatus as well as P. ostreatus originated from Chitila forest were able to utilize the crude oil as a source of carbon and energy in their metabolism.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Mihaela Monica DINU, Ana-Cristina FĂTU, Sorin ŞTEFAN, Ana Maria ANDREI

Interactions between the entomopathogenic bacteria Bacillus thuringiensis and chemical pesticides used for corn crop protection is one of the most important factors that influence the effectiveness of the entomopathogenic microorganism. Bacterial biopreparates based on B. thuringiensis could be used along with chemical pesticides. The effect of chemical ingredients on bacteria viability is mandatory and it should be conducted first. Interactions between the entomopathogenic bacteria B. thuringiensis and chemical pesticides occurs when chemicals and bacterial biopreparates are applied simultaneously or mixed together. Selectivity on some biological parameters of B. thuringiensis was tested by making a mixture of B. huringiensis with chemical pesticides. Different concentrations of chemical pesticides were mixed with sporulated and vegetative bacterial cultures. The effects of chemical plant protection products on sporulation and vegetative growth of B. thuringiensis were monitored. The paper presents the results of experiments aimed at determining the influence of some chemical pesticides used for corn crop protection on the B. thuringiensis multiplication and sporulation.

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

Rhodiola rosea L. is an endangered medicinal plant due to over harvesting in Bulgaria and in other European countries. The root and rhizomes are rich in pharmacologically and therapeutically active substances like flavonoids, phenolic acids that make the plant of commercial importance. The seed propagation in nature is very poor as far as only of 2 to 30 % of the seeds germinate depending on the ecologically geographic conditions. Thus, in vitro techniques are suitable for propagation of this species. In vitro propagation is possible by direct and indirect organogenesis. The latter is much more difficult in many species, including golden root. The present study aimed to understand the conditions, which provoke undifferentiated tissue initiation and development of shoots. The effects of different plant growth regulators in various concentrations oncallus induction and indirect plant regeneration were investigated. Regenerative callus was received on Murashige and Skoog medium containing 2,4- Dichlorophenoxyacetic acid (0.1 mg Г1)within 28 days. The adventitious buds were differentiated when the calli were subcultured on Murashige and Skoog (1962) medium supplemented with 6-benzylaminopurine (1.0 mg Г1) and indole-3-acetic acid (0.1 mg Г1) within 4 - 5 weeks. Half-strength solid MS with indole-3-butyric acid (2.0mg Г1)and IAA (0.2 mg Г1) exhibited the best in vitro rooting. These results contribute to the understanding of processes of growth and development in vitro of Rhodiola rosea and possibilities for selected of valuable clones and establishment of propagation schemes.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Tatiana BOCLACI, Larisa CREMENEAC

Worm compost is one of the final products obtained as a result bioconversion technology of organic waste by worm cultivation. The product obtained is a natural organic fertilizer ecological, composed of grains of various sizes, color dark brown, odorless, hygroscopic with long acting. In this article are presented the results of research obtained in the field experiment during the period of three years.The experiment was organized in field conditions of Technological-Experimental Station 'Maximovca'.As research material was used worm compost-organic fertilizer and peas variety 'Renata'. In experiment were included 3 groups,with a surface such (two-experimental, one-control). Experimental on the batches before sowing, was incorporated organic fertilizer dose of 4t/ha and 3t/ha from dejections of cattle, as a result of use of technology bioconversion of organic waste by worm culture. The control group was grown peas with natural background. The research was conducted in order to assess the influence worm compost on the quality of peas.In the outcome research found that worm compost influences the beneficial the development at the phases phenology of the agricultural crops. Early development of agricultural crops at different phases phenology conditional increasing the quality of production the harvest, resistance in the adverse climatic conditions and at different maladies, allowing obtaining output ecological agricultural. Analysis of research results obtained revealed that worm compost has a positive impact on the quality of output of pea by increasing total nitrogen, crude protein and the decrease content of nitro compounds. The nitrogen content as total and crude protein in the samples of pea grown with fund worm compost, increased by properly with 42,38%-126,50% si 42,37%-127,50% and nitro compounds diminished by 5,76%-65,11%.Thus, into results of the investigations it was found improve the quality of peas intended grown with fund worm compost compared with the cultivated fund natural.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Ovidiu IORDACHE, Călina Petruţa CORNEA

The experiments explored the interactions and antifungal properties of silver nanoparticles, against a model microorganism, Aspergillus niger.Scanning Electron Microscopy analysis were used for assessment of structural alterations done to fungal cells and hyphae, coupled with Energy Dispersive X-ray Spectroscopy (EDAX). The toxicity of the silver nanoparticles was tested using two methods: liquid exposure to the solution containing silver NPs,and spraying the NPs solution directly on the fungal culture. Analysis revealed significant cellular alteration due to the exposure to silver nanoparticles as well as effects on the growth of Aspergillus niger strain, in comparison to deionized water treatment, used at control sample. Microscopic SEM images revealed that silver nanoparticles treated hyphae were damaged on cell walls level, inducing plasmolysis, while EDAX analysis revealed strong silver depositions in the damaged areas of vegetative cells and spores walls, aspects that could be correlated with silver presence on the affected sites.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Daniela BALAN, Florentina ISRAEL-ROMING, Petruta Calina CORNEA, Evelina GHERGHINA, Gabriela LUTA, Florentina MATEI, Mihai CURTASU

The industrial processing of leather has a high environmental impact due to the heavy use of polluting chemicals in the tanning process. Microorganisms can be used in order to degrade natural fibers like fur, leather and cotton because they synthesized enzymes that can break chemical bonds in these materials. Some proteolytic enzymes, like collagenases, have a number of industrial applications in fur and leather industry and, moreover, are nontoxic and ecofriendly.This paper reports the purification and characterization of a fungal collagenase produced by an Aspergillus strain. Aspergillus oryzae Mi 156 and Aspergillus ochraceus Mi 153 were tested for their capacity to degrade native collagen. Enzymatic activity and protein content were determined using spectrophotometrical methods. The best results regarding collagenolytic activity were obtained for fungal strain Mi 156. The enzyme was separated by ammonium sulphate precipitation and analyzed for its optimum pH and temperature. The effect of some activators and inhibitors on the enzymatic activity was also tested. The results indicated 8 – 8.3 as optimum pH and 35 – 40

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Iulia RAUT, Mariana CONSTANTIN, Gelu VASILESCU, Melania Liliana ARSENE, Luiza JECU, Tatiana SESAN

Pathogens cause world-wide economically significant diseases in numerous agricultural, horticultural and ornamental crops. Most of the pathogens are difficult to control by conventional fungicides. Biocontrol represents an economical,environmentally friendly alternative to chemical pesticides for diseases produced by phytopathogens. Trichoderma strains have received particular attention as biocontrol agent of fungal plant pathogens. The present work is focused on the optimization of growth and sporulation of antagonistic Trichoderma T36. Assessment of microbial cultures was done by measuring the fungal colony growth on solid medium. Likewise, visual and microscopically observations were performed. Trichoderma T36 was cultured on different nutrient media and M1 medium, a Czapek-Dox medium supplemented with sodium phosphate, ammonium chloride and malt extract, was selected for further experiments. A wide range of carbon sources has been tested replacing initial source in M1 medium. The best results were obtained in media with fructose as carbon source. As expected, ammonium dihydrogen phosphate was found to be the best nitrogen source for Trichoderma T36 cultivated on M1 medium and colony diameter decreases in the following order:NH4H2PO4<NH4Cl<NH4NO3=NaNO3<KNO2<KNO3=NaNO2<urea. Fungal growth was excellent at temperatures of 26 - 37°C and pH range of4.0 – 5.5.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Chokri MESSAOUD1, Amina BENABDALLAH2, Mohamed BOUSSAID1

Alexanders (Smyrnium olusatrum) has long been regarded as a food and medicinal plant. The essential oil composition of S. olusatrum leaf, flower and fruit was characterized by high proportion of furanosesquiterpenes (51.66-69.35%).Furthermore, quantitative differences among plant parts were observed for the majority of oil components. Among all organs significant variability in fatty acids composition were also observed. Main constituents were found to be polyunsaturated fatty acids (37.74-49.36%).The total phenolic, flavonoid and carotenoid contents varied significantly between plant parts. Flower extract exhibited the highest contents of total phenolic (48.97 mg GAE/g) and flavonoid (52.63 mg RE/g). The β-carotene and lycopene contents were in the range of 4.55-26.14 mg/100g, and 8.00-49.45/100g, respectively. Methanolic extracts and essential oils of different organs were found to possess antioxidant activities, as determined by scavenging effect, chelating activity and β-carotene-linoleic acid model system. Extracts and essential oils showed a strong inhibitory activity against α-amylase. However, the level of biological activity varied according to extracts and organs.

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