Production of Novel Energy Gases in Bioprocesses Using Undefined Mixed Cultures.

Three phases of matter intermingle in various environments. The phenomena behind these fluctuations provide microbial cultures with beneficial interphase on the borderlines. Correspondingly, a bioreactor broth usually consists of a liquid phase but also contains solid particles, gas bubbles, technical surfaces, and other niches, both on a visible scale and microscopically. The diffusion limitation in the suspension is a remarkable hindrance to the reaction sequence during production. It must be overcome technically. Gas flow into the reactor could serve this purpose, and the outgoing stream or bubbling contains volatile products. The various mixing elements or gas flows should be moderated if shear forces disturb the cell growth, biochemical production, enzymatic activity, or any other crucial biological or physicochemical parameters. The focus is to optimize energy production in the form of liberated gases or their mixtures. Many combustible flows need to get purified, depending on their purpose, for example, for various engines. They provide novel sources for traffic in the air, streets, roads, and waterways, not forgetting space technology dimensions.On the other hand, industrial fuels are often used as mixtures of gases or gases with other substances. This approach may facilitate the utilization of side streams. Also, municipal energy needs can be fulfilled by microbial gases. Microbial mixed cultures could play an essential role in the big picture of sustainable industries, living and agriculture, exhibiting an excessive total effect on societies' multifactorial development. The gas phase is the key to realizing their potential.Gaseous emissions are inherent part of all forms of microbial metabolism, both aerobic and anoxic ones. Carbon dioxide is liberated both in respiration and fermentation, but the microbiota also binds volatile carbon compounds. CO2 is also a raw material for plant cultivation, e.g., in greenhouses or in algal pools which both represent the first steps of food chains. Additionally, they produce biomass to produce energy, biochemicals, nutrition, and soil improvement. Gaseous products of the mixed microbial cultures are valuable sources for energy production as purified gases (e.g., biomethane, biohydrogen) or as mixtures (e.g., bio-hythane, volatiles). These relatively simple molecules also serve as supplies for other hydrocarbons (e.g., methanol). Also, many microbial metabolites serve as fuel sources (e.g., bio-oil) and substrates for further biosynthesis. This versatility of potential technological options in energy making and for industrial processes could offer huge opportunities for green energies and sustainable industries, transportation, or municipalities. In the agriculture sector, the complete recycling also includes the consideration of gas phase. This aspect provides increasing sources for clean food production. Moreover, the chemoautotrophic bacteria, including the archaeal strains, could emanate novel streams of biobased products for human use.The bioprocess always consists of a biological component and a reactor or vessel solution, plus its control and adjustment means. Some project examples are taken up introducing the combinations of these two technological mainstreams, which should be in "symbiosis" for the best results. This novel approach could lead the human activities in industries, agriculture, and municipalities into "no waste" situations. At the same time, new global resources for economically feasible and sustainable raw material sources and processes thereof will emerge. In this novel technological ecosystem, connectivity to biosphere will return and remain our societies on healthy foundations, thanks to the microbes and their communities. This chapter introduces some of the potentials.