Sustainable saline microalgae co-cultivation for biofuel production: A critical review

Microalgae have gained increased attention as a viable, eco-friendly and alternative source of green bioenergy. To compete in the fuel market, saline microalgae cultivation for biofuel production would need to be economically sustainable and co-cultivation of saline microalgae using only saline water and recycled nutrient can potentially be the best solution to reduce the excessive use and prompt downsizing of natural resources like fresh water and fertilizers. This review provides a critical analysis on the selection of potential biofuel producing marine, halotolerant and halophilic microalgae. Here we proposed a microalgae co-cultivation strategy from seawater salinity (35ppt) to salt saturation (300ppt) with biofuel as the main output. We focused that adaptation of a co-cultivation strategy could reduce 95%, 74% and 51% of the overall nutrient waste compared to the monoculture of marine, halotolerant and halophilic microalgae. This paper also highlights a cultivation strategy using both mono and mixed culture over the period of increased saline condition and compares mass industrial-scale biofuel production from microalgae in three sites in Western Australia.