The objective of the present work was to determine the effect of pretreatment by extrusion on the biogas and biomethane yield of lignocellulosic substrates such as maize silage and maize straw silage. The biogas yields of the substrates before and after treatment were compared. Moreover, energy efficiency of pretreatment by extrusion was analyzed in order to assess the applicability of the process in an agricultural biogas plant. Extrusion tests were carried out in a short single-screw extruder KZM-2 in which the length-to-diameter ratio of the screw was 6:1 and rotational speed was 200 rpm. The biogas yield tests of the plant substrates after extrusion were carried out in a laboratory scale, using 15 biofermenters operated in a periodic manner, at a constant temperature of 39°C (mesophilic digestion) and controlled pH conditions. The gas-emission analysis was performed using a certified gas analyzer from Geotech GA5000. Pretreatment by extrusion was observed to improve the quantity of methane generated: in terms of fresh matter for maize silage subjected to extrusion, the methane yield was 16.48% higher than that of the non-extruded silage. On the other hand, maize straw silage after extrusion gave 35.30% more methane than did the same, non-extruded, material. Differences in yields relative to dry organic matter are also described in this paper. Taking into account the amount of energy that is spent on pretreatment and the generated amount of methane, the energy balance for the process gives an idea of the economics of the operation. For maize silage, energy efficiency was lower by 13.21% (-553.2 kWh/Mg), in contrast to maize straw silage, where the increase in energy was 33.49% (678.4 kWh/Mg). The obtained results indicate that more studies on the pretreatment and digestion of maize silage are required in order to improve the efficiency of its use for making biogas. To fully utilize its potential, it is necessary to know thoroughly the effect of the extrusion process and of biogas production on energy efficiency at different conditions.

Probiotics and probiotic therapy have been rapidly developing in recent years due to an increasing number of people suffering from digestive system disorders and diseases related to intestinal dysbiosis. Owing to their activity in the intestines, including the production of short-chain fatty acids, probiotic strains of lactic acid bacteria can have a significant therapeutic effect. The activity of probiotic strains is likely reduced by their loss of viability during gastrointestinal transit. To overcome this drawback, researchers have proposed the process of microencapsulation, which increases the resistance of bacterial cells to external conditions. Various types of coatings have been used for microencapsulation, but the most popular ones are carbohydrate and protein microcapsules. Microencapsulating probiotics with vegetable proteins is an innovative approach that can increase the health value of the final product. This review describes the different types of envelope materials that have been used so far for encapsulating bacterial biomass and improving the survival of bacterial cells. The use of a microenvelope has initiated the controlled release of bacterial cells and an increase in their activity in the large intestine, which is the target site of probiotic strains.

This paper presents the results of research on biocomposites made of the mixture of post-extraction rapeseed meal, microcrystalline cellulose and various fruit pomace (chokeberry, blackcurrant, apple and raspberry pomace). The biocomposites were made in the process of mechanical thickening by means of a heated mould (die and stamp) which is located between two heating elements installed on a hydraulic press. The presented research combines mechanical engineering and material engineering issues. The physical and mechanical tests of obtained biocomposites included mechanical strength measurements, thermogravimetric analyses (TGA), colour change tests and scanning electron microscopic (SEM) tests of the internal structure after breaking the sample. In addition, Fourier transform infrared spectroscopy (FTIR) tests were carried out. Generally, the bend tests and Young’s modulus were significantly increased, for example, biocomposites with an addition of chokeberry pomace had the flexural strength higher by approximately 25% in relation to the primary sample. Furthermore, it is interesting to note the increase of water contact angle of these biocomposites by 40% in relation to the primary sample. The research indicates the potential for using fruit pomace for the needs of biocomposite production.

The aim of this work was to examine the effect of temperature and time on mepiquat and chlormequat pesticides' formation during the barley malt roasting process. The study was conducted for roasting of green malt and kilned malt. The barley used for the study was of the ecological type and verified by us to be free of any quaternary ammonium pesticides. In our study, we observed the formation of chloromequat (CHLM) along with mepiquat (MPQ). Both the compounds share the similarity in quaternary ammonium structure but to the best of our knowledge, it is the first report where CHLM formation has been observed during the roasting process. Additionally, we tried to study the effect of processing parameters (temperature and time) on the quantity of MPQ and CHLM formed during the process, using response surface methods. Additionally, the effect of process parameters (time and temperature) on the color parameter of luminosity (L*) values was also studied using the response surface methodology. The key factor which determined the amount of compounds produced in the course of roasting was found to be temperature; on the other hand, duration of roasting was observed to be of lesser effect. In the process of roasting dry malt, the CHLM presence was detected at a temperature above 433 K (160°C), while the MPQ content was found to be present at a temperature above 442 K (169°C). In the case of green malt, the temperature at CHLM and MPQ content was detected and was found to be higher than kilned malt. We also observed that CHLM formed at lower temperatures and shorter roasting time as compared to MPQ.

The current state and the future of the biofuels for transport sectors in Poland were presented in the paper. Because of the importance of legal conditions, crucial directives and acts affecting the shape of these sectors were discussed. The scoring multicriteria M.E. Porter method was used to research attractiveness of the national biofuel sectors, i.e. the sectors of biodiesel and bioethanol produced from edible material (so-called first gene­ration biofuels) as well as the sector of bioethanol produced from inedible material, mainly from lignocellulose (so-called second generation biofuel). Various factors of macro- and microenvironment of first generation biofuels caused regular reduction of their attractiveness. However, the sector of second generation bioethanol, which is not produced at industrial scale in Poland now, is characterized by relatively high and growing attractiveness.