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Production of biofuel from lignocellulosic biomass is relatively low due to the limited knowledge about natural cell wall loosening and cellulolytic processes in plants. Industrial separation of cellulose fiber mass from lignin, its saccharification and alcoholic fermentation is still cost-ineffective and environmentally unfriendly. Assuming that the green transformation is inevitable and that new sources of raw materials for biofuels are needed, we decided to study cell death—a natural process occurring in plants in the context of reducing the recalcitrance of lignocellulose for the production of second-generation bioethanol. "Members of the enzyme families responsible for lysigenous aerenchyma formation were identified during the root hypoxia stress in Arabidopsis thaliana cell death mutants. The cell death regulatory genes, LESION SIMULATING DISEASE 1 (LSD1), PHYTOALEXIN DEFICIENT 4 (PAD4) and ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) conditionally regulate the cell wall when suppressed in transgenic aspen. During four years of growth in the field, the following effects were observed: lignin content was reduced, the cellulose fiber polymerization degree increased and the growth itself was unaffected. The wood of transgenic trees was more efficient as a substrate for saccharification, alcoholic fermentation and bioethanol production. The presented results may trigger the development of novel biotechnologies in the biofuel industry. [ABSTRACT FROM AUTHOR]

Effects of soaking aqueous ammonia pretreatment were considered for fast-growing poplar wood in the context of bioethanol production. The milled Populus trichocarpa wood with a particle size of 0.43 to 1.02 mm was pretreated at two temperatures (50 °C and 90 °C) and two concentrations of ammonia solution (15% and 20% w/w) for 20 h. The lignin content decreased by 46% in the biomass treated with the most severe conditions. After enzymatic hydrolysis, the sugar yield was analysed, and the results indicated that increased temperature and ammonia concentration during pretreatment resulted in higher glucose content. Additionally, changes in the degree of polymerization and available pore volume were investigated. [ABSTRACT FROM AUTHOR]

Preliminary studies are presented showing to what extent nutrients available in the growth environment of Kombucha microorganisms affect the physical and mechanical properties of synthesized cellulose. With an increase in the amount of sucrose in the growth medium and with the presence of additional nutrients, peptone and tea extract, the thickness and strength of the biopolymer increased, while elongation was reduced. The best physical and mechanical parameters were obtained for bacterial cellulose from cultures with the addition of 10% sucrose and 0.25% peptone content. The increase in elongation correlated with the decrease in the degree of polymerization, which means that in media rich in nutrients, the number of molecules building the polymer decreases. The presented data is important in order to select ingredients that will help synthesize bacterial cellulose with the desired physio-mechanical properties. [ABSTRACT FROM AUTHOR]

Pine-wood (Pinus sylvestris L.) was thermally modified at temperatures of 160°C and 200°C for 2, 6 and 10 hour periods, respectively. The severe conditions of the heat treatment resulted in decreased mechanical properties (compressive strength and modulus of elasticity) and a decrease in the degree of cellulose polymerization. A comparison of selected mechanical properties and the degree of cellulose polymerization indicated that there was a relationship between them and the temperature and duration of the heat treatment. [ABSTRACT FROM AUTHOR]