Acetone-butanol-ethanol (ABE) fermentation produces acetone, butanol, and ethanol, which are clean and sustainable energy sources with high energy densities. The ABE fermentation encounters butanol toxicity, by-products formation, and generation of lignin-derived inhibitors. The implementation of the low-lignin substrate, effective pretreatment, and biofuel coproduction would enhance the fermentation efficiency. Thus, this study investigated the use of sonication pretreated Chlamydomonas mexicanabiomass as a cost-effective substrate to produce bioH2and ABE using Clostridium acetobutylicumto demonstrate effective production of biofuels through ABE fermentation. Sonication enhanced the recovery and bioaccessibility of carbohydrates (74%) and proteins (52.4%), and their efficient utilization for bioH2and volatile fatty acid (VFA) production. The bioH2yield from sonicated C. mexicanabiomass (2.9mL/g-carbohydrate), was ~1.5 times higher than that attained from non-sonicated biomass (1.97mL/g-carbohydrate). Subsequently, VFAs generated in the acidogenic phase (1.5g/L acetate, and 6.05g/L butyrate) were used to produce 0.54 g-ABE/g-carbohydrate through ABE fermentation. Thus, this study demonstrates that both soluble carbohydrates (28g/L) and proteins (14g/L) from pretreated microalgal biomass were efficiently converted to 110.2mL bioH2and 20.84g/L ABE. These soluble carbohydrates and proteins could be used for high-energy biofuel production through ABE fermentation with minimum waste generation.