The high cost of biofuel production and low efficiency of captured energy are major factors that limit the large-scale use of algae for biofuels. The integration of the ADP into the production of other high-value products (e. g., food supplements, phar­maceuticals, and clean water) from algae is likely to make AD economically attrac­tive for biofuel generation.

5.3.1 AD Integrated into Other Algal Biofuel Production Pathways

There are several algae to biofuel conversion technologies, such as lipids extraction followed by transesterification, thermochemical hydroprocessing, phototrophic microbial fuel cell (PMFC), and algal hydrogen production. These processes gener­ate large quantities of waste algal biomass, residues, or by-products. The ADP is a prospective technology that can convert these waste materials into valuable fuel.