Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Angela CASARICA, Corina BUBUEANU, Ana Despina IONESCU, Ioana NICU

Bacterial cellulose (BC) has a variety of applications in biomedical fields. However, the native BC lacks certain properties, which limits its applications in various fields. The trend is nowadays towards the development of organic polymers using natural materials. In this sense, the possibility of obtaining new composite biomaterials with improved properties will prove as an interesting solution for achieving green composites BC, satisfying the need to explore minimal cost, biodegradable and renewable materials. Following these principles, this paper presents some of our studies carried out in order to obtain new eco-friendly composite biomaterials based on BC and valuable natural products such as sericin, propolis and royal jelly with appropriate biomedical applications. The main objective consisted in the biosynthesis and characterization of bacterial cellulose-based composites (BC) combined with natural products with antimicrobial properties.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXII
Written by Ancuţa CRÎNGAŞU (BĂRBIERU)

The developments of the winter pea crop represent a major challenge to expand plant protein production in temperate areas. Breeding winter cultivars requires the combination of freezing tolerance as well as with high seed yield and quality. In this paper we present data obtained from the F3, F4 and F5 lines of winter peas selected from the four hybrid populations (Specter/F95-927; F98-492/Windham; F95-927/CHECO; Specter/CHECO) and tested at NARDI Fundulea in the year 2017. At these lines were determined winter hardiness, earliness, yield and plant height in comparation with the three winter peas controls (Specter, Checo and Windham). The results shown that several news F5 lines of winter peasrealized till 6.5 t / ha, exceeding the control varieties and had similar to or better earliness and winter hardiness than that of the parental forms.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Roxana Gh. MANEA, Ioan I. ARDELEAN

In this paper there are presented experiments aiming to investigate the nutrient removal, either from the influent or from efluent of a wastewater treatment plant. The time of contact was 7 days. In order to determine the ratio volume of water – algal biomass we increased the volume of water and the retention time to 4 days. In the study photosynthetic micro-organisms were used, either free or immobilized, aiming to put them to work for consuming the nutrients. In relation mass / volume of 10 grams wet weight of free photosynthetic micro-organisms in 1,000 milliliters input water, removal efficiency of total nitrogen was 15% on the first day, 29% on the second day and 33% on day 4, while total phosphorus removal efficiency was 31% in the first day, 57% on second day and 80% on day 4. In relation mass / volume of 10 grams wet weight of free photosynthetic micro-organisms in 1,000 milliliters effluent water, removal efficiency of total nitrogen was 40% on the first day, 66% on day 2 and 79% on day 4, while the removal efficiency of total phosphorus was 22% on day 1,50% on day 2 and 67% on day 4. Experiments with photosynthetic microorganisms immobilized in an artisanal cage showed greater efficiency of removing nutrients (nitrate decreased by 70% and phosphorus by 50%) compared to experiments with free photosynthetic micro-organisms (nitrate was removed by 64% and total phosphorus by 39%) subjected to the same experimental conditions.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Livia APOSTOL, Corneliu Sorin IORGA, Claudia MOȘOIU, Gabriel MUSTĂȚEA, Șerban CUCU

Milk thistle (Silybum marianum) is an annual or biennial plant of the Asteraceae family that and usually grows in dry, sunny areas in Romania, but throughout in the world.The milk thistle seeds have been used since ancient times to treat a large variety of liver and gallbladder disorders. Theoprastus (IV century B.D.) and Plinius (1st century A.D.) were the first to report the medicinal benefits of this plant. All parts of the plant can be used, but the milk thistle seeds are considered to be the most medicinally potent for therapeutic use. The seeds and extracts of the milk thistle plant are a well established herbal food for protecting, detoxifying and regenerating the liver, one of the most important organs of the human body. We explored the physico-chemical properties as well the amino acids content of the milk thistle partially defatted seeds, The obtained results revealed that partially defatted milk thistle seeds are a good source of protein (20.35%), lipids (11,69%), total carbohydrates (38.16%) from which crude fiber (27.24%). This by-product presents a high mineral content (mg/100g): calcium (912), magnesium (433), iron (80,5), zinc (7,38) and copper (2,69). The partially defatted milk thistle seeds protein contained markedly amounts of essential amino acids such as arginine, leucine valine and lysine.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Mustafa GERMEC, Fatma Kubra KARTAL, Hazal GULDALI, Merve BILGIC, Asli ISCI, Irfan TURHAN

Growth curves are used in a wide range of applications such as crop science and biotechnology. Besides, mathematical models for fermentation can provide more information about kinetic of cell growth, and also promote the control and optimization of cell growth during fermentation. The main objectives of this study were undertaken not only plotted the cell growth curves, determined the specific growth equations, and calculated the kinetic parameters belong to Scheffersomyces stipitis strains (ATCC 58784 and 58785) but also to modelled their cell growths by using modified logistic and modified Richards models. The results indicated that the specific growth curves of ATCC 58784 in glucose and xylose mediums were y=0.3047×Abs600-0.2656 and y=0.2322×Abs600+0.4329, respectively. For ATCC 58785, they were y=0.2639×Abs600+0.0282 and y=0.2323×Abs600+0.6211, respectively. Furthermore, for ATCC 58784, maximum growth rate and doubling time values in glucose and xylose media were 0.23, 0.11 g/L/h and 2.45, 8.58 h, respectively. For ATCC 58785, they were 0.33, 0.11 g/L/h and 2.51, 7.66 h, respectively. In addition, modified logistic and modified Richards models were tested in order to describe cell growth profiles during fermentation by S. stipitis strains. Results indicated that these models can serve as a universal equation to fit cell growth. Moreover, validation of these models demonstrated that cell growth was all predicted accurately (slope=0.96 and 0.97, R2=0.998 and 0.998 for ATCC 58784 in xylose media by modified logistic and modified Richards models, respectively; slope=1.01 and 1.01, R2=0.995 and 0.995 for ATCC 58785 in xylose media by modified logistic and modified Richards models, respectively).

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Andreea TICAN, Nicoleta CHIRU, Mihaela CIOLOCA, Carmen BĂDĂRĂU

National Institute of Research and Development for Potato and Sugar Beet Brasov in 2016 INCDCSZ investigated two hydroponic systems to see the behavior of different potato Romanian varieties (Braşovia, Castrum, Marvis and Sarmis) regarding the following parameters: the number of minitubers/plant and weight of minitubers/plant. As hydroponic systems it was used one with circulating nutrient solution and another one with static layer of nutrient solution and for both cases the substrate used was perlite. Regarding the average weight of minitubers/plant, the plants culture on circulating nutrient solution had a beneficial influence comparative with culture on static stratum of nutrient solution, which recorded a highly significant difference in minituber weight compared to the first mentioned, statistically assured. Analyzing the number of minitubers using the hydroponic culture, relative to control variety (Brasovia with 5.10 minitub./pl.) shows that the Castrum variety gets the best results with a positive significant distinct difference (+5.90 minitub./pl.) followed by variety Marvis with a positive significant difference (+5.10 minitub./pl.). Varieties influence on weight mintub./pl. shows that the difference is very significant positive for Marvis variety (+42.49 g), compared to control variety and insignificant for the other varieties. From the obtained data we recommend using hydroponic system with nutrient solution circulating.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Irina SMEU, Elena Mirela CUCU, Alina Alexandra DOBRE, Enuța IORGA

Sixteen samples of breakfast cereals purchased from the Romanian market were studied in order to evaluate the possible occurrence of mycotoxins. The influence of microbiological and physical-chemical attributes that may determine the incidence of the toxins was studied. A BIOLOG system was used for the identification of the fungal strains. A sandwich-type enzyme –linked immunosorbent assay (ELISA) method was optimized and validated in-house for the quantification of two mycotoxins: deoxinivalenol (DON) and zearalenone (ZEA). The validation of the method was based on following performance parameters: accuracy (measured as percent error), precision (measured as coefficient of variance), reproducibility and repeatability (precision within- and between-day and analyst variability), limit of detection (LOD) and limit of quantification (LOQ). Recovery of the method was tested at low, medium and high levels of the working range (three concentration levels) for each mycotoxin in spiked breakfast cereal samples. According to the results, all samples presented levels far below their legal limits.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by RATU SAFITRI, ATHENA DINANTY, GUSTAN PARI, MOH. NURZAMAN

The purpose of this study was to obtain effective dose of hydrolase enzyme (α-amylase, hemicellulase, cellulase and amyloglucosidase) to produce highest levels of reducing sugars and dextrose equivalent (DE), and also to obtain the best microbial consortium in the fermentation of cellulose from pulp waste to produce bioethanol. This research used descriptive and experimental methods. The descriptive method was used in the optimization of hydrolase enzyme dosage, while the experimental method was used in cellulose of reject pulp fermentation. Parameters used in this study consist in ethanol content, reducing sugar content, microbial population and DE. Our results showed that the highest levels of reducing sugars in the optimization process of α-amylase enzyme was obtained at a dose of 0,52 μL g-1 whereas hemicellulase enzyme was at a dose of 2/3 or 0.00067 g g-1 and cellulase as well as amyloglucosidase was at a dose of 1 + 1 or 0.83 μL g-1 and 0,56 μL g-1, respectively. Additionally, the most effective and optimum fermentation was obtained by a consortium of Kluyveromyces marxianus and Zymomonas mobilis (K2), with ethanol content and fermentation efficiency as much as 6.27 and 59.48%, respectively. High levels of ethanol produced was also supported by the lowest reducing sugar content of 1.32% with the average of DE 1.69. Moreover, ethanol yield (Yp/s), maximum specific ethanol productivity (qp) and cell yield (Yx/s) were also obtained at 21, 76 and 26%, respectively. We observed that consortium K. marxianus and Z. mobilis (K2) reached the highest logarithmic phase at 36^th hour, with a population of 11,80x1010 cfu mL-1.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Roxana SPULBER, Mariana-Graţiela VLADU, Ovidiu POPA, Narcisa BĂBEANU

Bee pollen is a fine powder gathered from different plant species, enriched and transformed by bees into a complex bee product. Most bioactive properties of bee pollen, including antimicrobial activity, have been attributed to phenolic compounds. The aim of this study was determination of botanical origin, total phenolic content, flavonoid content and antimicrobial properties of three different pollen types from Romania against some plant microbial pathogens. Due to the fact that bioactive compounds of bee pollen depends strongly on the plant source, we tested extracts of fresh monofloral and polyfloral bee pollen. The ethanol 70% was used for pollen extraction. In this study, three microbial agents were tested: two bacterial strains represented by Erwinia carotovora (subsp. carotovora) ICCF 138, Xanthomonas campestris ICCF 274 and one fungal strain represented by Aspergillus niger ICCF 92. Furthermore, total phenolic and flavonoid contents were carried out using Folin-Ciocalteau procedure and aluminum chloride spectrophotometric method, respectively. Qualitative screening of pollen extracts antimicrobial activity was tested by disc diffusion method. The palynological investigations allowed us to identify the botanical origin of bee pollen loads, represented by species of eight different genera. Pollen sample extracts revealed high values for phenolic and flavonoid contents and also demonstrated that possess antimicrobial activities. We tried to established if the total phenolic or flavonoid content were related to the phytopathogenic antimicrobial activity. Our results indicated that bee pollen could be considered a promising natural source of plants protection.

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Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Yasin OZDEMIR, Sefik KURULTAY

Genetic variation was reported as an important factor effects quality of table olive. So that researchers aimed to develop new cultivar which had high table olive characteristics than that’s of standard cultivar. This research was aimed to determine characters of raw and processed fruits of 4 crossed olive genotypes which had been reported by previous studies as promising cultivar for registration according to agronomic characteristics. Fruits of Manzanilla cultivar which is the most important green table olive cultivar in Spain were used for comparison. Number of olives per kilogram, flesh to seed ratio, water, oil, total and reducing sugar, and phenolic compounds were analyzed. Sensory and salt analyses also were applied to processed olives. For green table olive production; olives were debittered by 2% NaOH and then put in brine which contained 5% salt at pH4,5. At 4th day of keeping the olives in brine, 107CFU/mL Lactobacillus plantarum were inoculated to the brine for fermentation until pH fall to 3,8.All the olives of genotypes had enough reduced sugar content (>2 %) for fermentative microorganisms and higher olive weight than Manzanilla but only olive of BK013 had higher flesh to seed ratio than Manzanilla. After processing hydroxytyrosol losses were determined in the range of 30,25-88,88 % and processed olives of MT038 had higher hydroxytyrosol content this is precious for nutrition physiology of consumer. Olives of BK013 and GK131had bettertable olive and sensory characteristics so that they have potential for registration as new table olive cultivar.

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