Biomass as a Resource

Schematic of generation and use of biomass illustrating closed elemental cycles. 

In this chapter, we will focus on the sustainability and efficiency of processes, and show that what seems or is meant to be green not always turns out to be green, sometimes against our intuition. As is common in this book, thermodynamics and some of its most relevant concepts will be used to analyze claims on the achievements of a process or route. The claim will be made that a product or process can only be called green after a proper assessment has been made. Often, such an assessment has necessarily a multidisciplinary character with contributions from disciplines with which we may be less familiar. 

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There are in principal four different methods to use biomass as a resource for biobased products. They differ from each other in the degree of chemical processing involved. 

The research work presented in this paper was financed by the Ministry of Science and Technological Development, Project Wood biomass as a resource of sustainable development of Serbia 20070-TP. 

The Fe203 catalysts treated with tellurate ion are effective for the selective conversion of ethanol to acetone (183). The synthesis of acetone from ethanol (2EtOH + H20 - Me2CO + C02 + 4H2) is of interest from the point of view of using biomass as a chemical resource. 

Another factor is the potential economic benefit that may be realized from the utilization of both waste and virgin biomass as energy resources due to current and future environmental regulations. If carbon taxes are ever imposed on the use of fossil fuels in the United States as they have been in a few other countries to help reduce undesirable automobile and power plant emissions to the atmosphere, additional economic incentives will be available to stimulate development of new biomass energy systems. Certain tax credits and subsidies are already available for commercial use of specific types of biomass energy systems (Klass, 1995). 

Naftali Muriithi (Kenyatta University, Kenya) has recognised the potential value in municipal waste as a resource. With increasing population, waste is also increasing rapidly. However this waste is difficult to recycle because it tends to be very heterogeneous in nature. It may be a mix of domestic and industrial materials and can also contain medical waste. A specific opportunity is to make use of nutrients present in biomass ash from domestic waste. Key factors to make this work will include more proactive government policy and constructing the right infinstructure. 

Obviously, the photosynthetic potential of plants with respect to the production of biomass as a renewable resource in sustainable production cycles has found actual attention and has been defined in many recent national and international research programs. A special variant of such endeavors has been formulated as New Phytotechnology by the Austrian group of Othmar Ruthner and coworkers [7] and this will be dealt with in the following section. 

To really appreciate the rationale behind current studies of microbial xylanases, it is necessary to consider a broad view that takes into account not just their intrinsic interest, but also their undoubted commercial potential. The structural polysaccharides cellulose and hemicellulose together account for greater than 50% of plant biomass and are consequently the most abundant terrestrial organic molecules. The value of plant biomass as a renewable resource is thus immediately apparent (23). 

Summing up, it is the production and supply of biomass rather than the demand for fuel or materials which limits the use of biomass as a renewable resource. In this context it is important to note that chemical production requires far lower amounts of carbon than fuel production. For example, in the United States, the chemical products segment consumed just over 3% of the total US petroleum consumption in 2007 (FitzPatrick et al., 2010). This opens an economic opportunity for the development of bio-sourced chemical products since the value of the chemical industry is comparable to the fuel industry, but requires only a fraction of the biomass (FitzPatrick etal.,2010). 

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