Biological processes production

Biological—Biochemical Processes. Fermentation is a biological process in which a water slurry or solution of raw material interacts with microorganisms and is enzymatically converted to other products. Biomass can be subjected to fermentation conditions to form a variety of products. Two of the most common fermentation processes yield methane and ethanol. Biochemical processes include those that occur naturally within the biomass. 

Dinitrogen is fixed either by natural processes or by industrial ammonia (qv) production (1,8,9). The estimates for the aimual biological contribution range around 100-200 x 10 t. Industrial fixation contributes about 50 x 10 t/yr for fertilizer uses (see Fertilizers). Other processes, eg, lightning and combustion, are estimated to fix about 30 x 10 t/yr. Thus the biological process represents the majority (ca 65%) of the total aimual fixation rate, contributing about three times as much as the commercial production of fertilizer. 

The purpose of this subsection is to introduce the reader to the tech-niqiies and methods used to recover materials, conversion products, and energy from solid wastes. Topics to be considered include (I) processing techniques for solid waste, (2) processing techniques for hazardous wastes, (3) materials-recoveiy systems, (4) recovery of biological conversion products, (5) therm processes, and (6) waste-to-energy systems. 

A number of biological processes result in the marine production of gases that have a greenhouse role, similar to water vapour and COj. In low oxygen environments, of the sort discussed in the next section, methane is produced by anaerobic bacterial decay ... 

Major bioprocess products are in the area of chemicals, pharmaceuticals, energy, food and agriculture, as depicted in Table 1.2. The table shows the general aspects, benefits and application of biological processes in these fields. 

To answer these questions, at first mass balance is required to determine conversion and how much air to supply into the fermentation broth. The substrate consumption or production rates must be set as a start. To demonstrate suitable answers to the above statements, we may approach the questions by reviewing a few biological processes and illustrating all the assumptions and process conditions. 

Oxidation-reduction reactions in water are dominated by the biological processes of photosynthesis and organic matter oxidation. A very different set of oxidation reactions occurs within the gas phase of the atmosphere, often a consequence of photochemical production and destruction of ozone (O3). While such reactions are of great importance to chemistry of the atmosphere - e.g., they limit the lifetime in the atmosphere of species like CO and CH4 - the global amount of these reactions is trivial compared to the global O2 production and consumption by photosynthesis and respiration. 

D. Das and T. Nejat Veziroglu, Hydrogen Production by Biological processes a Survey of Literature , Int. J. Hydrogen Energy, 2001, 26, 13. 

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