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As the pretreatment process is the most expensive and energy-consuming step in the overall second generation bioethanol production process, it is vital that it is studied and optimized in order to be able to develop the most efficient production process. The aim of this paper was to investigate chemical and physical changes in biomass during the process of applying the explosive decompression pretreatment method using two different gases-N 2 and synthetic flue gas. The explosive decompression method is economically and environmentally attractive since no chemicals are used-rather it is pressure that is applied-and water is used to break down the biomass structure. Both pre-treatment methods were used at different temperatures. To be able to compare the effects of the pretreatment, samples from different process steps were gathered together and analysed. The results were used to assess the efficiency of the pretreatment, the chemical and physical changes in the biomass and, finally, the mass balances were compiled for the process during the different process steps of bioethanol production. The results showed that both pre-treatment methods are effective in hemicellulose dissolution, while the cellulose content decreases to a smaller degree. The high glucose and ethanol yields were gained with both explosive pretreatment methods at 175 • C (15.2-16.0 g glucose and 5.6-9.0 g ethanol per 100 g of dry biomass, respectively).

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Results from an investigation of the mechanical size reduction with the Szego Mill™ as a pretreatment method for lignocellulosic biomass are presented. Pretreatment is a highly expensive and energy-consuming step in lignocellulosic biomass processing. Therefore, it is vital to study and optimize different pretreatment methods to find a most efficient production process. The biomass was milled with the Szego Mill™ using three different approaches: dry milling, wet milling and for the first time nitrogen assisted wet milling was tested. Bioethanol and biogas production were studied, but also fibre analysis and SEM (scanning electron microscope) analysis were carried out to characterize the effect of different milling approaches. In addition, two different process flows were used to evaluate the efficiency of downstream processing steps. The results show that pretreatment of barely straw with the Szego Mill™ enabled obtaining glucose concentrations of up to 7 g L−1 in the hydrolysis mixture, which yields at hydrolysis efficiency of 18%. The final ethanol concentrations from 3.4 to 6.7 g L−1 were obtained. The lowest glucose and ethanol concentrations were measured when the biomass was dry milled, the highest when nitrogen assisted wet milling was used. Milling also resulted in an 6–11% of increase in methane production rate during anaerobic digestion of straw.

Biodegradable and compostable tableware is significantly more environment and nature friendly than disposable tableware and drinkware made of plastic. Tableware made of wheat bran, but also corn and rice bran is already commercially available. It is reasonable to use the by-products of the milling of also other cereals, like rye bran, barley bran and oat bran, for the production of tableware. The aim of this research was to explore the possibilities for the production of tableware and drinkware from the by-products of the milling of wheat and also other cereals like rye and oat bran. In order to achieve the aim, compacts were moulded from rye bran and oat bran and mixtures of bran (wheat bran and rye bran) using various work modes. The moulding of the compacts included different temperatures of the mould, moulding durations and compressive forces. The mechanical properties like density and flexural str ength of the compacts were determined and the compostability of the compacts was studied. The test bodies were placed inside a compost bin to check their compostability and to determine the duration of composting.