Biomass biological process

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. 

Ahluwalia and Goyal94 have pointed out some disadvantages of biosorption such as the early saturation of biomass, which can be a problem since metal desorption is necessary prior to further use, irrespective of the metal value. Furthermore, the potential for biological process improvement is limited because cells are not performing an active metabolism. 

Biomass-based processes for the production of hydrogen can be either thermochemical or biological and can produce this clean carrier directly or through an intermediate, storable product. Also, the use of coproducts has to be addressed to improve the process economics and in view of the sustainability of using this natural resource. A recent overview of the status of the different technologies is given in an IEA/NREL review5 and further by Czernik et al.8... 

Biomass can generate energy in many different forms. Refuse derived fuels (MSW) can produce steam or electric power. They can also be converted to other fuels using chemical or biological processes producing ethanol or methanol. The wood and pulp industries use their wastes to provide a significant part of their heat, steam, and electricity needs. 

In the present chapter, anaerobic digestion (AD) is chosen as an illustrative example of biological WWTPs. It is a set of biological processes that take place in the absence of oxygen and by which organic matter is decomposed and converted on one hand into biogas i.e., a mixture of mainly carbon dioxide and methane) and, on the other hand, into microbial biomass and... 

Natural sources of CO include CO from biomass burning and the oxidation of organics such as methane and isoprene, CO from biological processes in soils, CO from vegetation and termites, and CO from the ocean. 

This proportionality is called the yield of the particular biological process, and it is commonly denoted as Y. For carbon-limiting substrates oxidized by aerobes, biomass yields are usually near 0.5 g biomass-g"1 carbon (Neidhardt et al., 1990). Using yield information relevant to a particular compound/microbial species combination, we can now relate the production rate of new cells to the disappearance rate of the chemical of concern ... 

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