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.

The main dynamic characteristics of biochemical methanol formation by the oxidation of methane using a biocatalyst were studied. The biocatalyst is based on cells of bacteria Methylosinus sporium B-2121, both suspended in a medium and immobilized in the poly(vinyl alcohol) cryogel. The change in the methane concentration and the biocatalyst amount affects the productivity of the system, the maximal concentration of methanol in the cultural liquid, and the rate of methanol accumulation. The most part of the dynamic characteristics are described by extremal curves. The experimental conditions were optimized prior to experiments. The use of the immobilized biocatalyst makes it possible to enhance the productivity of the process more than fivefold compared to that of the free cells and to achieve the highest methanol concentration in the medium: 62±2 mg L−1.

Biomethanol is one of the perspective sources useful for direct application for the production of biodizel. Methanol is used in chemical industry in a variety of ways: it is a building block for other chemicals; it can be used directly as antifreeze and as a precursor to other compounds. The biomethanol is very attractive source for production of biofuel that can be from manufactured renewable raw materials. The biological oxidation of methane by bacteria with methan monooxigenase activity is discussed in literature as one of approaches to obtaining of methanol under low enough temperature (2535°С) and regular pressure [Xin, 2004, Mehta, 1991, Yu, 1998]. It is considered, that biological method of methanol production is more attractive as compared to chemical method of methanol production, realized at 350-400 °С and 8-10 MPa [Bahnisch, 2005; Lapkin, 2004]. Application of biotechnological approach to the methanol production should guarantee satisfied yields of target product and stability of functioning of biological systems with retaining of constant levels of productivity for a long period of time. At the same time, it is necessary to avoid the intensive growth of cells in the bioreactor, since the growth could base on the utilization of methanol by cells (Fig. 1). As a result the concentration of required product could decrease.

By using a bioluminescence ATP assay, we have determined the minimal concentrations of some biocorrosion inhibitors (Kathon, Khazar, VFIKS-82, Nitro-1, Caspii-2, and Caspii-4) suppressing most common microbial corrosion inducers: Desulfovibrio desulfuricans, Desulfovibrio vulgaris, Pseudomonas putida, Pseudomonas fluorescens, and Acidithiobacillus ferrooxidans. The cell titers determined by the bioluminescence method, including not only fissiparous cells but also their dormant living counterparts, are two-to sixfold greater than the values determined microbiologically. It is shown that the bioluminescence method can be applied to determination of cell titers in samples of oil-field waters in the presence of iron ions (up to 260 mM) and iron sulfide (to 186 mg/l) and in the absence or presence of biocidal corrosion inhibitors.

By using a bioluminescence ATP assay, we have determined the minimal concentrations of some biocorrosion inhibitors (Katon, Khazar, VFIKS-82, Nitro-1, Kaspii-2, and Kaspii-4) suppressing most common microbial corrosion agents: Desulfovibrio desulfuricans, Desulfovibrio vulgaris, Pseudomonas putida, Pseudomonas fluorescens, and Acidithiobacillus ferrooxidans. The cell titers determined by the bioluminescence method, including not only dividing cells but also their dormant living counterparts, are two- to sixfold greater than the values determined microbiologically. It is shown that the bioluminescence method can be applied to determination of cell titers in samples of oil-field waters in the presence of iron ions (up to 260 mM) and iron sulfide (to 186 mg/l) and in the absence or presence of biocidal corrosion inhibitors.