Figure 4

SEM images of fermentative bacteria along with non-sonicated or sonicated algal cells. Non-sonicated algal cells (a and b): (a) non- or (b) 10 min sonication. Sonicated algal cells (c and d): (c) 15 min or (d) 60 min sonication. The circles indicate fermentative bacteria present on the intact surface of algae, while the squares show ruptured algal cells allowed fermentative bacteria to access the inner space of the algal cells, resulting in high hydrogen/ethanol production.