MicroalgCurrent algal cultivation has been mainly performed in open ponds or closed photobioreactors in which algal cells are suspended in liquid and harvested through 30 sedimentation, flocculation, filtration and/or centrifugation devices. Due to the issue with separating large volumes of water from algae, there is a growing interest in developing biofilmbased cultivation methods that allow algae to attach to a substrate and form a biofilm. Attachment-based cultivation systems have been less studied than suspended algae systems even though they have received increased interest in the past five years. Examples of these attachment-based systems are outlined in Table 1. One major benefit of these attachment-based systems is that harvested biomass typically contain 80-95% of water, much higher than that in suspension culture systems (Johnson and Wen, 2010).