Energy and emission properties of burley tobacco stalk briquettes and its combinations with other biomass as promising replacement for coal.

As a tobacco producer, Serbia has to deal with large amounts of leftover tobacco stalks after harvesting. One option for this type of biomass is to burn it, but burning is not encouraged in Serbia, since the levels of its combustion products have not been investigated yet. The aim of this study was therefore to determine the elemental composition, ash and nicotine content, heat values, and composition of gaseous combustion products of tobacco stalk briquettes and to see if their mixing with other types of biomass available in Serbia could improve their ecological profile. We made 11 different types of briquettes: six of pure raw materials, including burley tobacco stalks, sunflower head remains, wheat straw, corncob, soy straw, and beech sawdust and five by mixing tobacco stalks with these other raw materials in a 50:50 mass ratio. All briquettes meet the ecological criteria regarding the emission limits for nitrogen oxides (NOx), sulphur dioxide, carbon monoxide, and carbon dioxide. Nicotine content in flue gases (<10 mg/kg) is far below the maximum level allowed by the European Union. Heat values of all biomass samples are acceptable, although lower than those specified for solid biofuels (≥16.0 MJ/kg), save for corncob and beech sawdust and their mixtures with tobacco stalks. Our findings therefore encourage the use of tobacco stalks as a viable biofuel.

Bacterial Microbiota Isolated from Cysts of Globodera rostochiensis (Nematoda: Heteroderidae).

The potato cyst nematode (PCN) Globodera rostochiensis is a plant parasite of potato classified into a group of quarantine organisms causing high economic losses worldwide. Due to the long persistence of the parasite in soil, cysts harbor numerous bacteria whose presence can lead to cyst death and population decline. The cysts of G. rostochiensis found in two potato fields were used as a source of bacteria. The universal procedure was applied to extract DNA from bacteria which was then sequenced with 16S primers. The aims of the study were to identify bacterial microbiota associated with the PCN populations and to infer their phylogenetic relationships based on the maximum likelihood and Bayesian phylogeny of the 16S sequences. In addition, the impact of the most significant climate and edaphic factors on bacterial diversity were evaluated. Regarding the higher taxonomy, our results indicate that the prevalent bacterial classes were Bacilli, Actinobacteria and Alphaproteobacteria. Phylogenetic analyses clustered Brevibacterium frigoritolerans within the family Bacillaceae, confirming its recent reclassification. Long-term climate factors, such as air temperature, insolation hours, humidity and precipitation, as well as the content of soil organic matter, affected the bacterial diversity. The ability of cyst nematodes to persist in soil for a long time qualifies them as a significant natural source to explore the soil bacterial microbiota.

Case Study upon Foliar Application of Biofertilizers Affecting Microbial Biomass and Enzyme Activity in Soil and Yield Related Properties of Maize and Wheat Grains.

This study evaluated the effects of the application of microbial inoculants (N-fixing Klebsiella planticola and Enterobacter spp.), two rates of composite mineral fertilizers, and their combination on microbial biomass carbon (MBC), dehydrogenase (DHA), and proteinase activity (PTA) in Lessivated Cambisol and yield-related properties of maize and wheat grains in a two-year trial. Unfertilized soil was used as a control variant. MBC was measured using the chloroform fumigation-extraction method, DHA was determined spectrophotometrically by measuring the intensity of the formed red-colored triphenyl formazan, while PTA was determined using a titration method by measuring the degree of gelatine decomposition. In grain samples, P was determined spectrophotometrically, K-by flame emission photometry, N-on an elemental carbon/nitrogen/sulfur (CNS) analyzer, and crude proteins-by calculation of N content. Measuring both crops' yield was carried out at the end of the vegetation. The results indicated that mineral fertilizers are not, in general, negative for soil microbiota when used in the context of sustainable agriculture without monoculture. There is a significant increase in the values of soil MBC, DHA, and PTA in the variants with combined application of bacterial inoculants and lower rates of mineral fertilizers. The highest values of these parameters were determined in the period with a better distribution of precipitation during the vegetation period of the year. The mentioned combination also resulted in a higher grain yield of maize and wheat comparing to the application of lower rates of the NPK nutrients solely. The combined application of high rates of mineral fertilizers and bacterial inoculants resulted in significantly increased N, P, K, and protein content in the grains of crops, and the same applied to yield. Concluding, studied bacterial inoculants can be used to specify the replacement of nitrogen fertilizers, stimulating the microbial biomass and enzyme activity in the soil, helping to ensure that the supply of nutrients contributing to an optimized yield of crops is maintained.

Microelements and Heavy Metals Content in Frequently Utilized Medicinal Plants Collected from the Power Plant Area.

The effectiveness of medicinal plants is mainly associated with their active constituents, but one of the major quality problems frequently encountered is their high trace metals content that can be associated to extensive pollution of the environment where medicinal plants grow. Therefore the aim of this research was to evaluate the content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn and As in selected and frequently used medicinal plants, including chicory, broadleaf, common comfrey and dandelion. The plant material was collected from their wild habitats in the area of highly developed power plant activity during the summer of 2015. Plant analyses were done according to ICP methodology, using ICAP 6300 ICP optical emission spectrometer. The obtained results showed that the content of As, Cd, Co, Mn, Ni and Zn in the investigated medicinal plant species was below the maximum permissible concentration, while in all parts of all studied plants the concentration of Cr was toxic. The toxic concentrations of Cu were determined in root and aerial parts of chicory and common comfrey, and the toxic concentrations of Fe in root and aerial parts of dandelion and broadleaf plantain, and in aerial parts of common comfrey. However, high but not toxic content of Pb was found in aerial parts of chicory. It can be concluded that medicinal plants from the studied growing site are not appropriate for use in alternative medicine and that a determination of trace metals content in these plants must become a standard criterion for evaluation of their quality.