Factors affecting algae biofilm growth and lipid production: A review

Algae is recognized as a potentially valuable source of biofuels and biochemicals; however, a major limitation to commercialization is in the high cost of harvesting, de-watering, and downstream processing of dilute algae biomass when it is grown planktonically. Growing algae as a biofilm offers potential advantages for biomass processing because biofilms are immobilized and orders of magnitude more concentrated. For these reasons there has been an emerging interest in algae biofilm biofuel research over the past several years. Additionally, there has been a considerable amount of work on understanding algae biofilms in nature, and on using algae biofilms for tertiary wastewater treatment. This review paper draws from all of this literature to describe algae biofilm composition, and their growth responses to the key environmental factors affecting growth and internal lipid concentrations; the emphasis being on optimizing biomass and lipid productivity. Additionally, the paper summarizes key things known about planktonic algae growth and bacterial biofilm growth in order to make inferences about the potential growth of algae biofilms. The paper identifies many key knowledge gaps in the potential for producing biomass and lipids from algae biofilm growth systems.