Utilization of the Carbohydrate Fraction Bioethanol and Biogas

There are two major options for the utilization of the carbohydrate fraction of the microbial biomass bioethanol and biogas (sometimes called biomethane). An excellent review on the possible utilization of the carbohydrate fraction has been recently published by Markou et al. (2013). When compared to the work being done on biodiesel, there are fewer studies that have been done on microalgal bioethanol and biogas. 

A critical parameter in the generation of biogas is the C/N ratio. Too much nitrogen may be inhibitory to the methanogenic bacteria, whereas too little nitrogen could lead to an 

Reference Harun and Shekharam Choi et al. Brown Brown Brown 

The steps after biogas generation differ according to the intended use. Direct combustion may be done in engines designed specifically for that purpose. If it is desired that the biogas be fed into the natural gas distribution network, then further purification is necessary. In addition to a few other requirements, the main criterion is that the purity of the methane must be at least 96% (Deublein and Steinhauser, 2008). 

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