Production of biofuels from pretreated microalgae biomass by anaerobic fermentation with immobilized Clostridium acetobutylicum cells.

The purpose of this work was to study the possible use of pretreated biomass of various microalgae and cyanobacteria as substrates for acetone-butanol-ethanol (ABE) fermentation by Clostridium acetobutylicum cells immobilized into poly(vinyl alcohol) cryogel. To this end, the biochemical composition of photosynthetic microorganisms cultivated under various conditions was studied. The most efficient technique for pretreating microalgal biomass for its subsequent conversion into biofuels appeared to be thermal decomposition at 108 °C. For the first time the maximum productivity of the ABE fermentation in terms of hydrogen (8.5 mmol/L medium/day) was obtained using pretreated biomass of Nannochloropsis sp. Maximum yields of butanol and ethanol were observed with Arthrospira platensis biomass used as the substrate. Immobilized Clostridium cells were demonstrated to be suitable for multiple reuses (for a minimum of five cycles) in ABE fermentation for producing biofuels from pretreated microalgal biomass.

[Effect of light-isotope water on growth of bacterial culture].

The stimulating effect of light-isotope water on microbial growth was demonstrated in bacterial culture Pseudomonas esterophilus. Nutrient medium was prepared of mineral salts and ethyl acetate as a source of carbon dissolved in light-isotope water with ppm 35 and 70; the control medium contained same components dissolved in distilled water. The investigation showed an increase in the number of bacterial cells in the exponential stage of growth in static culture in light-isotope water as compared with the control. Specifically, accretion made up 87.3 and 35.2% in light-isotope water with ppm 35 and 70, respectively. In an hour, the number of cell divisions increased by 6.7% and 3.3%, respectively. Therefore, light-isotope water stimulates the metabolic activity and, consequently, growth of bacterial cells.

[Pressure-regulated pulmonary ventilation with an inverse ratio of the duration of the inhalation and exhalation phases]. / Ventiliatsiia legkikh, reguliruemaia po davleniiu, pri obratnom sootnoshenii prodolzhitel'nosti faz vdokha i vydokha.

Clinical and physiological effects of pressure-regulated ventilation of the lungs using the inverse rate of inhalation to exhalation (PCV-IR) were studied in two groups of patients. No appreciable advantages of this mode of pulmonary ventilation in comparison with common ("volumic") method were observed in group 1 patients (following open-heart surgery) with moderately expressed respiratory disorders (PaO2/FIO2 = 340c13 and index of lung comprometation 0.7c0.04). At the same time, the level of the peak inhalation pressure in the airways at PCV-IR was reliably lower than during common artificial ventilation of the lungs (AVL). In patients with grave respiratory disturbances (PaO2/FIO2 = 93c10 and index of lung comprometation 6.88c0.56) application of this scheme brought about an improvement of pulmonary biomechanics and gas exchange, but the hemodynamics was virtually the same. It is noteworthy that the process of PCV-IR adaptation required a thorough preliminary "adjustment" of the ventilation parameters and took rather a long time in the majority of patients. Positive effects of PCV-IR may be due to several mechanisms: a slowing down (ramp-like) flow, limitation of the upper pressure during inhalation, prolongation of exhalation in comparison with inhalation, and a regulated level of internal positive end expiratory pressure. PCV-IR is recommended as a variant of respiratory support in the treatment of patients with severe involvement of the lungs, when the potentialities of common AVL are exhausted.