Many species of microalgae are encapsulated by a rigid cell wall and can be prob­lematic in anaerobic digesters (Chen and Oswald 1998; Golueke and Oswald 1959; Gonzalez-Fernandez et al. 2012a, b; Mussgnug et al. 2010; Samson and Leduy 1983; Sialve et al. 2009; Zamalloa 2012). Anaerobic digester associated bacteria need to be able to access the contents of the microalgae cells to allow the digestible components to be converted to methane biogas (Ward et al. 2014). The microalgae cell wall material and chemistry have a major influence on the biogas potential (Ras et al.

2010) , and some microalgae species have been shown to survive intact after 6 months within an anaerobic digester, changing to heterotrophic growth rather than photo­trophic growth (Mussgnug et al. 2010). Several studies conclude that a pre-treatment step is required to disrupt the cell wall to increase bacterial hydrolysis before addition to the anaerobic digester (Chen and Oswald 1998; Golueke and Oswald 1959; Mussgnug et al. 2010; Sialve et al. 2009; Zamalloa 2012). Within an integrated system, cell lysis or disruption is also essential for solvent extraction of the lipid fraction of microalgae biomass, allowing solvents to react with internal cell lipids (Lee et al. 2013). Therefore, microalgae cell wall disruption processes are essential for both lipid-based biofuel applications and for optimal anaerobic digestion. The multiple methods of disruption and cell lysis include mechanical, physical, thermal, chemical and enzymatic methods and have the twin applicability of allowing solvent to react with lipids increasing lipid yield in the extraction process and also microbial hydrolysis of the cell contents during anaerobic digestion (Ward et al. 2014). However, the cost of the extra pre-treatments must be considered within the anaer­obic digester and biofuel production systems as the energy consumption for the pre­treatment of microalgae biomass can be equal or higher than the energy gained from the microalgae cell (Lakaniemi et al. 2011; Lee et al. 2012, 2013; Lu et al. 2013; Sialve et al. 2009; Yen and Brune 2007).