MICROBIAL XYLANASE: A REVIEW

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Aglaia BURLACU, Călina Petruța CORNEA, Florentina ISRAEL-ROMING

Xylan is the major constituent of hemicellulose, the second most abundant natural polymer on earth. There are four main categories of xylans: arabinoxylans, glucuronoxylans, glucurono arabinoxylans and galacto glucurono arabinoxylans. The side chains of each xylan are being responsible for the solubility, physical conformation and reactivity of the xylan molecule with other components of the hemicellulose and therefore, influencing the mode and extent of enzymatic cleavage. Xylanases, as glycoside hydrolase members, are able to catalyse the hydrolysis of xylan, by breaking the β-1,4-glycoside linkages, in order to produce simpler compounds such as xylose. Because of the heterogeneity and complex chemical nature of xylan, the complete breakdown requires the action of several hydrolytic enzymes that are different considering their structure, the substrate specificities, their mode of action or biochemical properties. Many degrading microorganisms produce xylanases such as fungi (Aspergillus spp., Trichoderma spp.), bacteria (Bacillus spp., Streptomyces spp.), yeast (Cryptococcus spp.), marine algae etc. Depending on the source, microbial xylanases have different characteristics, that makes them useful for an application or another. Worldwide, the market of xylanases has expanded rapidly because of its potential in industrial use, especially in the biotechnological applications. In this review, are presented the significant aspects concerning the complete hydrolysis of xylan, and therefore of hemicellulose.

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BURLACU A., CORNEA C.P., ISRAEL-ROMING F. 2016, MICROBIAL XYLANASE: A REVIEW. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 335-342.

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MICROBIOLOGICAL QUALITY CONTROL OF A NEW PLANTS MIX EXTRACT FOR VETERINARY USE

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXI
Written by Tomina PURCARU, Camelia DIGUŢĂ, Florentina MATEI

The microbiological control of veterinary products needs an integrated approach, being part of the quality assurance in the pharmaceutical industry. During the production of a phytopharmaceutical product of veterinary use it is compulsory to have a standardized method for the quantification of the microbial charges (fungi and bacteria) from the raw vegetal material to the final product. Our work has been focused on the microbial charges of a new phytoimmunomodulator veterinary product based on Inula sp., Eupatorium sp. and Helleborus sp. For the product standardisation several attempts have been done and one part of the work was related to microbiological criteria fulfilment. The microbial charges have been quantified according to adapted method developed by the authors and correlated to limits recommended by European Pharmacopeia. In the case of the raw dried and grounded plants the total mesophilic aerobe bacteria load is much higher than the recommended limits, while the fungal load has reached almost the maximum recommended limits. Acceptable contents of coliforms and no traces of Salmonella have been detected in the final product. The phytopharmaceutical company to patent and produce the new veterinary product, should make efforts especially in the raw material procurements, as long as their actual sources comes with a much more higher content in aerobe bacteria than the recommended limits. Supplementary measures should be taken to avoid in this context the cross-contamination.

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PURCARU T., DIGUŢĂ C., MATEI F. 2017, MICROBIOLOGICAL QUALITY CONTROL OF A NEW PLANTS MIX EXTRACT FOR VETERINARY USE. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 115-120.

MUSHROOM MYCELIA CULTIVATION ON DIFFERENT AGRICULTURAL WASTE SUBSTRATES

Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Mihai Bogdan NICOLCIOIU, Gabriela POPA , Florentina MATEI

Increasing demand for edible or medicinal mushrooms has led to investigation into the suitability of sawdust and agricultural wastes as substrates for commercial production. Effective use of bio-resources by waste-free processing and production of nutraceuticals or ingredients for functional foods are the main directions in biotechnology. The aim of this work was to evaluate the growth capacity of mushroom mycelia on substrates of sawdust or agricultural wastes mixed with different amendments. Four variants of agricultural substrates (wheat and sorghum each of them mixed with CaSO4 and dolomite amendments) and seven mushroom species (Flammulina velutipes, Laetiporus sulphureus, Ganoderma lucidum, Ganoderma applanatum, Hericium coralloides, Trametes versicolor and Lepista nuda) were used. The mycelial cultures were initially grown in Petri dishes on 2 % malt extract agar or PDA media at 25°C in the dark. After one week, the mycelium of each mushroom species was transferred to different sterilized grain, wheat, sorghum or barley straws or sawdust as substrates with various amendments. Various degrees of grain coverage with mycelia depending on substrate and mushroom species were obtained. The results obtained give the possibility of high quality inoculum using cheap renewable resources and the future extension of the research at the mushroom farm for evaluating the effectiveness of this inoculum for fruiting bodies obtaining. Better utilization of these recyclable materials by mushroom cultivation releases important land surfaces and also eliminates the polluting factors from the terrestrial ecosystems. After finishing the culture cycle, the spent substrate represents a valuable reusable resource as constituent material in nutritional mixtures for horticultural cultures, in bioremediation of some degraded soils or contaminated with various pollutants, of waste water, having a positive impact on improving the sorrounding environment.

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NICOLCIOIU M.B., POPA G., MATEI F. 2016, MUSHROOM MYCELIA CULTIVATION ON DIFFERENT AGRICULTURAL WASTE SUBSTRATES. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 148-153.

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NEW BIOACTIVE COMPOSITES BASED ON BACTERIAL CELLULOSE AND NATURAL PRODUCTS

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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CASARICA A., BUBUEANU C., IONESCU A.D., NICU I. 2016, NEW BIOACTIVE COMPOSITES BASED ON BACTERIAL CELLULOSE AND NATURAL PRODUCTS. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 343-346.

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NITROGEN AND PHOSPHORUS REMOVAL FROM MUNICIPAL WASTEWATER USING CONSORTIA OF PHOTOSYNTHETIC MICROORGANISMS

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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MANEA R.Gh., ARDELEAN I.I. 2016, NITROGEN AND PHOSPHORUS REMOVAL FROM MUNICIPAL WASTEWATER USING CONSORTIA OF PHOTOSYNTHETIC MICROORGANISMS. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 286-292.

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NUTRIENT COMPOSITION OF PARTIALLY DEFATTED MILK THISTLE SEEDS

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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APOSTOL L., IORGA C.S., MOȘOIU C., MUSTĂȚEA G., CUCU S. 2017, NUTRIENT COMPOSITION OF PARTIALLY DEFATTED MILK THISTLE SEEDS. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 165-172.

OBTAINING GROWTH CURVES FOR Scheffersomyces stipitis STRAINS AND THEIR MODELING

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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GERMEC M., KARTAL F.K., GULDALI H., BILGIC M., ISCI A., TURHAN I. 2016, OBTAINING GROWTH CURVES FOR Scheffersomyces stipitis STRAINS AND THEIR MODELING. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 263-268.

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OBTAINING MINITUBERS BY APPLYING METHOD OF CULTURE ON SUBSTRATES INDUSTRIAL

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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TICAN A., CHIRU N., CIOLOCA M., BĂDĂRĂU C. 2017, OBTAINING MINITUBERS BY APPLYING METHOD OF CULTURE ON SUBSTRATES INDUSTRIAL. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 66-71.

OPTIMIZATION AND EVALUATION OF ELISA IMMUNOASSAY FOR MYCOTOXIN DETECTION OF BREAKFAST CEREALS

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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SMEU I., CUCU E.M., DOBRE A.A., IORGA E. 2017, OPTIMIZATION AND EVALUATION OF ELISA IMMUNOASSAY FOR MYCOTOXIN DETECTION OF BREAKFAST CEREALS. Scientific Bulletin. Series F. Biotechnologies, Vol. XXI, ISSN 2285-1364, 265-269.

OPTIMIZATION OF HYDROLASE ENZYME DOSAGE IN THE PROCESS OF CELLULOSE HYDROLYSIS OF REJECT PULP AND BIOETHANOL FERMENTATION BY MICROBIAL CONSORTIUM

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 36th hour, with a population of 11,80x1010 cfu mL-1.

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SAFITRI R., DINANTY A., PARI G., NURZAMAN M. 2016, OPTIMIZATION OF HYDROLASE ENZYME DOSAGE IN THE PROCESS OF CELLULOSE HYDROLYSIS OF REJECT PULP AND BIOETHANOL FERMENTATION BY MICROBIAL CONSORTIUM. Scientific Bulletin. Series F. Biotechnologies, Vol. XX, ISSN 2285-1364, 300-308.

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