Biorefineries carbon sources

Selection of raw materials is essential for economic amino acid produaion in general. According to a decentralized biorefinery concept amino acid producers are often located close to sugar or starch plants in order to decrease transport costs. Depending on geographical location of the manufacturing plant carbon sources like cane molasses, beet molasses, or starch hydrolysates from corn, potato, or cassava are used. While molasses are... 

Biotechnology continues to be an important contributor to the biorefinery, especially for the conversion of carbohydrates. The paper by Richard describes a new approach for the fermentation of C sugars, providing methodology for more efficient conversion of biomass carbohydrates to EtOH. The contribution from Nakas discusses the bioproduction of polyhydroxyalkanoates using levulinic acid as a carbon source. Stipanovic describes new approaches for using hemicellulose as a chemical feedstock. 

One report stated that biorefinery-based fuel or chemical production is a strategy, framed to reduce GHG emissions. In practice, CO2 emissions produced by the biorefinery activities cannot be compensated for by the carbon fixation of plants, because a good majority of the plants are already exhausted through feedstock utilization. The situation exerted by biorefinery seems worse than petroleum-based biorefinery where at least there is a chance for CO2 to get sequestrated. This can be clearly visualized in Fig. 16.3. On the whole, it could be concluded that the forest-based biorefinery is not going to be feasible, as it converts all land-based carbon sources to CO2 and leaves no option for the emitted CO2 to get sequestrated (Delucchi, 2011). 

The biorefinery approach is the most sound in terms of truly exploiting the potential of an aquatic biomass, and this concept is now becoming accepted on a worldwide basis. In the biorefinery approach, the economic and energetic value of the biomass is maximized, although it must be emphasized that fluctuations in the prices of fossil carbon (coal, oil, gas) raises uncertainty regarding the opportunity to produce biodiesel from aquatic biomass. For example, when the oil price is below US 120 per barrel it is uneconomic to produce biodiesel in this way. On the other hand, an aquatic biomass demonstrates an excellent potential for use as a source of specialty chemicals, with some components also having added value as animal feeds or fertilizers. 

Angela Dibenedetto Associate Professor at the University of Bari-UNIBA (IT)—Department of Chemistry. Her scientific interests are focused on carbon dioxide utilization in synthetic chemistry, catalysis, coordination chemistry and organometallic chemistry, green chemistry, marine biomass (algae) production by enhanced carbon dioxide fixation, marine biomass as source of fuels and chemicals applying the biorefinery concept. 

Second-generation biorefineries are those that utilize lignocellulosic biomass as a raw material. Lignocellulosic biomasses are composed mainly of three polymers of plant cell walls cellulose, hemicellulose, and lignin. The advantage of this type of biorefinery is the recovery of the most abundant source of renewable carbon (Gruber and O Brien, 2002). 

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