Sugar cane, production data

The used BSG hydrolyzate conqjosition is shown in Table 2. It has approximately 26 g F of monosaccharides and a low level of microbial inhibitors, specially aliphatic acids, and furan derivatives compared to similar hemicellulosic hydrolyzates used for SCP production, e.g., eucalyptus wood [28] and sugar cane bagasse [7,8]. Also, it has a low content of phenolic compounds. Crude protein has a concentration of about 1.2 g F. Much of this nitrogen (about half) is in ammonia form, the rest as amino acids (data not shown). 

Apart from its use as a fuel, biomass gains increasing interest as feedstock for the chemical indusfry. The Brew project in which different biomaterials were assessed focus towards their potential in that sector [33]. A special role is played by the integration into the production of plastics, for which bio-based ethanol and subsequently polyethylene presents one alternative. As already stated, ethanol can be obtained from different sources. However, it seems that all data in the literature on greenhouse gas emissions and energy use for fermentation of Brazilian sugar cane and subsequent refinement to ethanol are based on the reports of one single researcher [34]. This is of course a limitation for the LCA. 

The data (and their sources) used to calculate the carbon contents, vq, and the conversion efficiency factors, cv, and the calculations themselves, are given in Appendix 2. As tq we use 0.61, 0.44 and 0.43 for rapeseed, maize, and sugar cane, respectively. We derive values of cv = 0.58 for rapeseed bio-diesel, cv = 0.37 for maize bio-ethanol, and cv = 0.30 for sugar cane ethanol production. 

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