Jerzy Tys

Comparison of biogas production from wild and cultivated varieties of reed canary grass

The chemical composition and efficiency of biogas production in the methane fermentation process of silages of wild and cultivated varieties of reed canary grass were compared. An attempt was made to answer the question on how the habitat and the way of utilization of plants affect chemical composition and biogas yield. Physicochemical properties such as dry matter, organic dry matter, protein, fat, crude fiber fraction, macro- and microelements content were considered. The anaerobic digestion process and FTIR analysis were also carried out. The results showed that the two varieties differ essentially in their physical and chemical properties. The cultivated variety was characterized by higher biogas yield (406Ndm(3)kg(-1) VS) than the wild one (120Ndm(3)kg(-1) VS). This was probably related to the chemical composition of plants, especially the high content of indigestible crude fiber fractions and ash. These components could reduce biogas quantity and quality.

Physical methods of microalgal biomass pretreatment

Abstract The prospect of depletion of natural energy resources on the Earth forces researchers to seek and explore new and alternative energy sources. Biomass is a composite resource that can be used in many ways leading to diversity of products. Therefore, microalgal biomass offers great potential. The main aim of this study is to find the best physical method of microalgal biomass pretreatment that guarantees efficient lipid extraction. These studies identifies biochemical composition of microalgal biomass as source for biodisel production. The influence of drying at different temperatures and lyophilization was investigated. In addition, wet and untreated biomass was examined. Cell disruption (sonication and microwave) techniques were used to improve lipid extraction from wet biomass. Additionally, two different extraction methods were carried out to select the best method of crude oil extraction. The results of this study show that wet biomass after sonication is the most suitable for extraction. The fatty acid composition of microalgal biomass includes linoleic acid (C18:2), palmitic acid (C16:0), oleic acid (C18:1), linolenic acid (C18:3), and stearic acid (C18:0), which play a key role in biodiesel production.

Microbiological Hazards Resulting from Application of Dairy Sewage Sludge: Effects on Occurrence of Pathogenic Microorganisms in Soil

The aims of this study were to (1) examine the extent of bacterial contamination of soils subjected to exposure to dairy sewage sludge applied to soils as measured by determination of number of bacteria from the Escherichia coli family and (2) determine the effects of dairy sewage sludge and straw on populations of other microbial species present in gray–brown podzolic soil. The gray–brown podzolic soil was formed from heavy loamy sand, which is characterized by the following granulometric composition: a sand fraction, 65%; a silt fraction, 19%; and a silt and clay fraction; 16%. The brown soil was formed from silt-loam and characterized by the following granulometric composition of silty–clay deposit: sand fraction, 8%; silt fraction, 48%; and clay and silt fraction, 46%. In dairy sewage sludge the total bacteria number as defined by Alef and Nannipieri (1995) was 51 × 104 colony-forming units (cfu)/ kg dry matter (dm), fungi total number 10 × 103 cfu/ kg dm, and E. coli bacteria 9.5 × 103 most probable number (MPN)/kg dm. In dairy sewage sludge mixed with straw, total number of bacteria and total number of fungi decreased to 103 and 102, respectively. Competition for nitrogen, glucose, and lactose and organic acids such as acetic and succinic with soil microorganisms, as well as soil conditions such as lack of oxygen, lower soil pH, and temperature, may account for the reduction in the number of E. coli bacteria in soils to which dairy sewage sludge was applied. Dairy sewage sludge may provide a beneficial impact on soil environment and adversely affect microorganisms such that dairy sewage sludge may be used as a safe organic fertilizer.

Use of the electro-separation method for improvement of the utility value of winter rapeseeds

Abstract The paper presents the results of a study of the use of electro-separation methods for improvement of the utility value of 5 winter rapeseed cultivars. The process of electro-separation of rapeseed was conducted on a prototype apparatus built at the Laboratory of Application of Electro-technologies in Agriculture, Lviv National Agriculture University. The process facilitated separation of damaged, low quality seeds from the sowing material. The initial mean level of mechanically damaged seeds in the winter rapeseed cultivars studied varied within the range of 15.8-20.1%. Verification of the amount of seeds with mechanical damage was performed on X-ray images of seeds acquired by means of a digital X-ray apparatus. In the course of analysis of the X-ray images, it was noted that the mean level of mechanical damage to the seeds after the electro-separation was in the range of 2.1-3.8%. The application of the method of separation of rapeseeds in the corona discharge field yielded a significant reduction of the level of seeds with mechanical damage. The application of the method in practice may effectively contribute to improvement of the utility value of sowing material or seed material for production of edible oil.

Populations of selected microbial and fungal species growing on the surface of rape seeds following treatment with desiccants or plant growth regulators.

The aim of this study was to determine the effects of desiccants and plant growth regulators on selected microbial species affecting rape seeds, with special emphasis on the growth of fungi and identification of the genus and species composition. The experimental material in the study was seeds of winter rape cv. Californium that were collected from the field during combine harvest. The chemical agents applied, both desiccants and growth regulators, generally decreased the populations of bacteria occurring on the surface of rape seeds. The responses of fungi depended upon the type of agent applied and were manifested as either stimulation or inhibition of the growth of the fungal species. The fungi isolated from the surface of rape seeds were characteristic of those found in the field environment (Cladosporium and Penicillium) and typical for those present on the surface of rape seeds (Alternaria).

Development of optimum substrate compositions in the methane fermentation process

Abstract The aim of the study was to assess the potential of organic wastes from the agriculture and food industry as co-substrate for biogas production, on the basis of physical and chemical parameters analysis and biogas yield in the process of methane fermentation. The experimental material consisted of carrot pomace, kale by-products and maize silage. Methane fermentation was conducted in bioreactors equipped with an automatic control and measurement system. The study indicated correct physicochemical properties in terms of high content of dry organic matter and also correct C/N ratio. That was reflected in high biogas yields which amounted to, respectively, 558 N dm3 kg−1 VS−1 for carrot pomace and kale by-products, and 526 N dm3 kg−1 VS−1 for maize silage. The study showed that the intensity of biogas production was varied and depended on the composition of fermented mixtures. Methane fermentation of organic waste mixtures significantly increased the amount of biogas efficiency compared to the fermentation of individual substrates. The successful run of the experiment indicates that a mixture composed of carrot pomace and kale by-products is a good substrate for the production of biogas.

Cultivation of Chlorella protothecoides in photobioreactors: The combined impact of photoperiod and CO2 concentration

Algal biomass is regarded as an alternative source for producing renewable fuels, given the chemical nature of storage products: lipids, starch, and proteins. Many factors affecting the production of microalgal biomass and lipid accumulation include the light and CO2 concentration, i.e. critical factors for determination of the biochemical composition of microalgal biomass. Our objective was to evaluate the effect of three different light/dark photoperiods (12/12 h, 16/8 h, 24/0 h) and the CO2 concentration (from air and 5% v/v CO2‐enriched air) on the growth rate, productivity, and changes in the biochemical composition of Chlorella protothecoides biomass. Continuous illumination stimulated growth under supplementation of air CO2. At 5% CO2, the maximum C. protothecoides growth rate was found under 16/8 light/dark cycles and longer duration of light yielded a decrease in the specific growth rate. The photoperiods and CO2 concentrations influenced the biomass productivity. Chlorella protothecoides produced biomass more efficiently at the 24/0 and 16/8 light/dark cycles under supplementation of air CO2 than at addition of 5% CO2. However, under the 12/12 light/dark cycle, biomass productivity was higher at 5% CO2. The light photoperiod greater than 16 h did not increase biomass productivity. These factors also influenced the content of lipids and carbohydrates. A maximal lipid content was observed for the 24‐h photoperiod for air CO2, whereas the addition of 5% CO2 affected lipid and carbohydrate production.

Comparison of selected parameters of biomass and coal

Abstract As a fuel, biomass differs in its properties from fossil fuels and acquisition thereof for energy purposes is limited; hence, the ongoing search for new bioenergetically useful plants. The article presents the results of physical and chemical analyses of seven species of perennial grasses: tall wheatgrass, tall wheatgrass ‘Bamar’, brome grass, tall fescue ecotype, reed canary grass, giant miscanthus, and sorghum. The research involved technical and elemental analysis as well as analysis of the ash composition performed in order to determine their potential use for combustion process. The measurement results were compared with those obtained for hard coal and agricultural biomass, which is widely used in the energy industry. The results suggest that perennial grasses can successfully be combusted with similar performance to coal if burned in appropriate combustion installations.

Far red‐dependent changes in the chemical composition of Spirulina platensis

The influence of far‐red light (FRL) was studied on the chemical composition of Spirulina platensis biomass. The following light compositions were used during the culture white light, blue‐red LED light (BRL) and BRL supplemented with FRL (BRFRL). Chlorophyll and phenol contents were measured by spectrophotometric methods, whereas presence of carotenoids, lipids, and phycobiliproteins were estimated by Fourier‐transform Raman spectrometry. Additionally, phenol content was investigated by fluorescence intensity of algae culture in the range of 430–650 nm. The content of chlorophyll and phenols in algae cells depended on the spectral composition of light and was the highest under BRL (16.7 ± 0.5 and 9.1 ± 0.6, respectively). It was shown that there is a positive linear correlation (R = 0.902 at p < 0.0000001) between the ratio of relative fluorescence intensity of S. platensis suspensions at 450 nm to the suspensions at 540 nm (F450/F540) and the content of phenolic compounds in the biomass. Changes in the F450/F540 ratio can explain approximately 80% changes of phenol contents in algae cells. Spirulina platensis Raman spectra demonstrated that the biomass of algae growing under white light and BRL had a significantly higher intensity of phycobiliprotein bands than the algae growing under BRFRL.

The Possibility of Meeting Greenhouse Energy and CO2 Demands Through Utilisation of Cucumber and Tomato Residues

The article examines the possibility of using residues from greenhouse cucumber and tomato cultivation as biomass for energy and CO2 production in order to meet greenhouse needs. Methane fermentation and combustion were compared. Moreover, the legitimacy of ensiling as a storage method for biogas plant was evaluated. The tested waste was found to be an unsuitable feedstock for the production of silage due to low sugar and high protein content. Fresh waste had a higher biogas yield than silage; however, its fermentation lasted longer. Furthermore, the results showed that, in the case of fresh residues, the methane fermentation proved to be a more energy-efficient process, while air-dry biomass is a more sustainable feedstock for combustion. The energy and CO2 balance showed that, regardless of the method used, the available quantity of waste is too small to meet the greenhouse needs.