Antibacterial activity of ethanol extracts of fifteen Bulgarian plants

A. Solak, S. Dyankova

Institute of Cryobiology and Food Technologies, 53 Cherni Vrah Str., 1407 Sofia, Bulgaria

(Manuscript received 1 September 2018; accepted for publication 16 January 2019)

Abstract. Analyses were performed of the antimicrobial activity of 15 herbs and spices (lemongrass, sour cherry, horseradish, ginger, St. John’s wort, common centaury, fig, clove, rose geranium, dill, rosemary, oregano, savory, smoketree and wild thyme) widely spread and used in Bulgaria and of some combinations thereof by the agar disk diffusion method. Total phenol content was the highest in the smoketree extract (43.80±1.50 GAE/ml), followed by rosemary (27.80±1.20 GAE/ml), clove (25.17±0.26 GAE/ml), wild thyme (24.83±1.20 GAE/ml), and oregano (23.50±2.00 GAE/ml) extracts. It was established that ethanol extracts of many tested plants showed inhibitory action against S. aureus and E. coli. The most potent effect was observed with extracts of St. John’s wort, smoketree and clove. With combination of plant extracts, very good results were demonstrated in mixtures of St. John’s wort with wild thyme, with savory and with clove. The said extracts may be used as active constituents in biopolymer matrices for development of functional antimicrobial films needed for food and pharmaceutical industries.

Zoo-hygienic assessment of lighting in semi-open freestall barns for dairy cows

D. Dimov

Department of Applied Ecology and Animal Hygiene, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 1 September 2018; accepted for publication 16 January 2019)

Abstract. The aim of the present study was to perform a zoo-hygienic assessment of lighting (natural and artificial) in different technological zones (stalls, manure and feed alleys) in semi-open freestall barns for dairy cows. The survey was conducted over a period of one year in 3 production buildings from 3 cattle farms located in three different areas of Southern Bulgaria – Stara Zagora District, Haskovo District and Plovdiv District. The building’s parameters were as follows: building No.1 – capacity 120 cows, 60.00/18.00/3.00m, 1080m2; building No.2 – capacity 120 cows, 66.00/18.00/3.00m, 1188m2 and building No.3 – capacity 500 cows, 90.00/45.00/3.30m, 4050m2. The premises lighting was measured with two combined apparatuses (Lutron EM-9300SD, 0-20000 lux and PU 150, 0-100000 lux), twice a month at 10.00, 12.00, 14.00, 16.00 and 18.00h at a height of 1m from the floor of the three technology zones. Summarized for all buildings, the light level varies widely by buildings, by seasons, by hours of reporting and by technological zones with limit values between 1 and 9810 lux. In all barns the most intense was the light above the feed alleys, followed by stalls and manure alleys; by hours of reporting during the day the level of lighting above the three technological zones was higher at midday (12.00-14.00h) compared to morning (10.00h) and afternoon (18.00h). Buildings No.1 and No.2 with a smaller built-up area provide more intensive lighting over all technological zones throughout all seasons compared to building No.3 with bigger built-up area: from 7.34 to 13.8 times over stalls, from 3.22 to 5.62 times over manure alleys and from 2.79 to 8.00 times over feed alleys. In buildings No.1 and No.2 there were prerequisites at least 16 hours of day light (photoperiod) to be provided during summer, autumn and spring, while in the winter months up to 8.00am and after 6.00pm the used artificial lighting was with low intensity and cannot provide the recommended over 160 lux intensity of the light. In building No.3 during most of the day for all seasons, the level of lighting above stalls and manure alley where the animals stay the longest time, the lighting level was lower than 160 lux. The factors ‘building’, ‘season’ and ‘hour of the day’ had a statistically significant effect (P<0.05-0.001) on the level of lighting in the three technological zones in the studied buildings. Of the associated factors, only the combination ‘season*hour of reporting’ had no significant effect on the lighting in the zones above the stalls and manure alleys.

Ecological stability and plasticity of maize hybrids in different groups of ripeness

M. Ilchovska

Maize Research Institute, 5835 Knezha, Bulgaria

(Manuscript received 1 September 2018; accepted for publication 3 December 2018)

Abstract. Ecological stability and plasticity of maize hybrids in different groups of ripeness – Knezha 307, Knezha 435, Knezha 509 and Knezha M625 by the traits grain yield and length of the ear was evaluated. The ecological parameters were determined by using the method of Eberhart and Russell (1966) and of Pakudin and Lopatina (1984). In the period of study (2014-2017) the hybrids demonstrate different plasticity and stability by the examined traits. The results of the analysis of the variances demonstrate reliable differences of the hybrids and the conditions for the two traits and primarily reliable interaction genotype – environment. The variances of the regression Si2 of all hybrids for the trait grain yield reliably differ from their theoretical value which determines them as plastic, i.e. responsive to more favourable conditions of growth. According to the values of bi the hybrid Knezha 435 (bi<1) is stable by the trait grain yield, the hybrids Knezha 307 and Knezha M625 are with values of bi close to one and have relatively medium stability and Knezha 509 with bi>1 is unstable. With reliable values of Si2 for the trait length of the ear is only the hybrid Knezha M625. The ecological stability of the other hybrids was evaluated by the value of the coefficient of regression (bi). Increased stability by this trait is demonstrated by Knezha 435, followed by Knezha 509. Knezha 307 is with medium stability (bi=1.1) by the respective trait.

Antioxidant properties and phytochemicals of three brown macro algae from the Dardanelles (Çanakkale) Strait

A.K. Ilknur1*, G. Turker2

1Department of Aquaculture, Faculty of Marine Sciences and Technology, Canakkale Onsekiz Mart University, 17100 Canakkale, Turkey 2Department of Food Technology, Canakkale School of Applied Sciences, Canakkale Onsekiz Mart University, 17100 Canakkale, Turkey

((Manuscript received 17 May 2018; accepted for publication 26 August 2018))

Abstract. This study was conducted to determine antioxidant properties and phytochemicals of brown algae Scytosiphon lomentaria (Lyngbye) Link, Cystoseira barbata (Stackhouse) C. Agardh, and Padina pavonica (Linnaeus) Thivy, collected from the Dardanelles (Çanakkale) Strait, Turkey, in February 2018. The antioxidant activity, total carotenoids, condensed tannins, and total content of phenolics and flavonoids in ethanol extracts were quantified. P. pavonica showed the highest antioxidant potential as well as the maximum content of phenolics and carotenoids. The total flavonoid contents changed from 1375.43±2.37 μg/g Ext. (C. barbata) to 2250.92±46.60 μg/g Ext. (S. lomentaria). The highest condensed tannins were found in C. barbata. According to results obtained, C. barbata, S. lomentaria and P. pavonica possess antioxidant activity and could be used in the food and feed industries.

Effect of wheat straw and cellulose degrading fungi of genus Trichoderma on soil respiration and cellulase, betaglucosidase and soil carbon content

D. Draganova*, I. Valcheva, Y. Kuzmanova, M. Naydenov

Department of Microbiology and Ecological Biotechnologies, Faculty of Plant Protection and Agroecology, Agricultural University, 12 Mendeleev, 4000 Plovdiv, Bulgaria

(Manuscript received 12 June 2018; accepted for publication 31 August 2018)

Abstract. Due to the intensive soil exploitation and increased mineral fertilization, the degradation of plant residues in the soil is becoming more difficult and slower over the years. This disturbs the structure of the soil and the nutritional balance and leads to a reduction in soil fertility. To solve the problem, microorganisms capable of degrading plant residues in the soil can be used. The purpose of this study was to investigate the effect of fungi of genus Trichoderma on the biodegradation of wheat straw in the soil by observation of the change in cellulase enzyme activity in the soil and the increase in soil biological activity. The highest basal soil respiration was noted at T2TUR (65.76 μgCO2) and T6 (53.69 μgCO2). During the entire straw degradation period, the highest endoglucanase activity was observed at T4 (285.0 μgGlu) and T6 (275.56 μgGlu), whereas the highest β-glucosidase was noted at T6 (5220.3 μgPNP/g/h) and T1UKR (5020.0 μgPNP/g/h). The presence of cellulose-degrading fungi positively affected the increase in the total amount of microbial biomass at the end of the study period, whereas the amount of Corg was increased in all straw amended variants. At the beginning of the process, CMCase correlated with the microbial carbon (r=0.896 for Cmic) and β-glucosidase activity was closely connected with both soil organic carbon and microbial carbon (r=0.819 for Corg and r=0.866 for Cmic). At the end of the investigated period a stronger correlation with Corg was observed.

Agricultural characteristics of sugar factory waste products

B.B. Aşık, S. Dorak


Department of Soil Science and Plant Nutrition, Faculty of Agriculture, Uludag University, 16059 Bursa, Turkey


DOI: 10.15547/ast.2018.03.049

(Manuscript received 17 May 2018; accepted for publication 16 August 2018)


Abstract. In this study, physical and chemical properties of sugar factory waste (sugar beet seed wastes) were determined. The following parameters were analyzed: pH, EC, organic matter, C:N ratio, total concentrations of N, P, K, Ca, Mg, Fe and Mn, and the content of Cd, Cr, Ni, Pb, Cu and Zn. The EC values of waste material were 8.96-10.25 dS/m. pH values varied from 4.96 to 7.30. Organic matter content changed between 86.54 and 89.02%. C:N ratio changed from 18.68 to 24.49. Total N content varied from 2.10 to 2.70%. Waste material contains different quantities of plant nutrients (N, P, K, Ca, Mg, etc.). The physicochemical characterization is important when planning the use and management of organic waste. Heavy metal concentrations of seed waste were below the regulatory limits of Turkey and the European Union. Finally, the compost from sugar factory waste products is of good quality and suitable for use as fertilizer in agriculture.


Theoretical analysis of the heat energy savings in wood pellets production

  1. R. Georgiev, K. Peychev, V. Dimova, Georgiev


Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria


DOI: 10.15547/ast.2018.03.048

(Manuscript received 4 June 2018; accepted for publication 6 August 2018)


Abstract. The report includes a theoretical analysis of the heat energy savings in the drying of wood biomass with desiccant fumes. With the current technological schemes for drying wood pellets most heat is lost with the exhaust fumes.To use the heat of exhaust fumes it is propose to utilize these by a heat exchanger recuperator type, which transfers part of the heat of the exhaust gas to the fresh air entering the dryer installation. Thus, about 25% of the heat for drying biomass can be saved. The report examines the relationship between outdoor temperature and condensation of moisture from the exhaust gases on the relative share of energy saved using a heat exchanger.

Differences in carbon forms under two land use types in Abia State, South-east Nigeria

B.N. Ndukwu1, D.N. Osujieke2, C.M. Ahukaemere1, P.E. Imadojemu2


1Department of Soil Science and Technology, Federal University of Technology, PMB 1526 Owerri, Imo State, Nigeria

2Department of Soil Science and Land Resources Management, Federal University Wukari, PMB 1020 Wukari, Taraba State, Nigeria


DOI: 10.15547/ast.2018.03.047

(Manuscript received 21 May 2018; accepted for publication 29 July 2018)


Abstract. The storage of carbon in the soil helps to sustain the ecosystem of our environment. However, this study was to determine the differences in carbon forms (total carbon, organic carbon and inorganic carbon) under selected forest and pasture land use types in Abia State, Nigeria. Two profile pits were sung on each of the land use types using free survey technique. The profile pits were sampled based on horizon differentiation for routine and special laboratory analyses. The data obtained were statistically analyzed for coefficient of variation and correlation. Total carbon had mean of 2.07% and 2.12% for profiles 1 and 2 under pasture land use and 2.46% and 2.45% for profiles 3 and 4 under forested land use. Organic carbon as indicated by the mean was higher in forest land (profile 3=1.85%, profile 4=2.09%) than in pasture land (profile 1=1.37%, profile 2=1.40%) while inorganic carbon was higher in pasture land (profile 1=0.70%, profile 2=0.72%) over forest land (profile 3= 0.39 %, profile 4= 0.36 %). Organic carbon had high variation (≥45.97% ≤ 49.38%) in profiles of the pastured land use while it had low – moderate variation (≥12.55% ≤ 27.03%) in profiles of forested land use. Also, inorganic carbon recorded moderate variation (≥16.12% ≤ 25.95%) in profiles of pasture and forest land use types. The forest land use type was determined to contain more forms of carbon when compared with the pasture land use type.

Heavy metals in organs of gudgeon (Gobio gobio L.) from Vardar River, R. Macedonia

R. Nastova*, V. Kostov, I. Ushlinovska

Institute of Animal Science, “Ss. Cyril and Methodius” University, Blvd. Ilinden 92 A, 1000 Skopje, Republic of Macedonia (Manuscript received 4 August 2017; accepted for publication 13 November 2017)

Abstract. Ecotoxicological examinations based on seven heavy metals (Fe, Cu, Zn, Mn, Cd, Pb and Cr) concentrations in organs of gudgeon (Gobio gobio L.) caught by 14 monitoring points at Vardar River in Republic of Macedonia were performed. The organ’s samples elements were read-out on AAS in flame and graphite cuvette. Significant increase of Pb and Cd contents in liver, gills and gonads of fish sampled downstream Skopje and the town of Veles was found. It should be pointed out that at times Cd concentrations in muscles were as high as 0.518 mg/kg which is significantly over the maximally allowed concentrations for human nutrition.

Biodiversity of the macrozoobenthos in some protected marine areas along Bulgarian Black Sea coast

E. Petrova*, S. Stoykov

Institute of Fish Resources, 9000 Varna, Bulgaria
(Manuscript received 30 August 2017; accepted for publication 6 November 2017)

Abstract. The aim of this paper is to establish the biodiversity status of the macrozoobenthos in some protected marine areas (NATURA 2000) along the Bulgarian Black Sea coast. The observation stations in the period 2010-2012 were within the frames of the following habitats: 1160 – Large shallow inlets and bays; 1110 – Sandbanks, slightly covered by seawater and Sublittoral mussel banks on sediment. In general, the data shows steady state compared to the 1980s, except for the area near Kamchia River, characterized by low biodiversity due to water pollution from the river inflow (with contaminants from agricultural and industrial sources in the upper river stream) and less salinity leading to marine mussel species reduction. In the border area, near the Emona zone, the black mussel catches varied between 160-600 kg in 2005, while only single specimens were detected in 2013. In the same field, the yield of Rapana venosa was within the limits of 5-40 kg in 2005 and between 80-160 kg in 2013. The established variability showed a dynamic balance between Mytilus galloprovicialis and Rapana venosa that pose a challenge for future stock of the black mussel and point the need of regular monitoring.