Future bioenergy source by microalgae-bacteria consortia: a circular economy approach

The potentiality of microalgae-bacteria consortia applied in a circular economy is acknowledged and explored; however, the commercialization of biofuel from microbial technology remains complex and controversial regarding the practicability of the technology. This review provides a concise and comprehensive analysis of various extraction techniques of the microalgae-bacteria consortium, algae cultivation methods, and biofuel production processes. The conversion processes are critically reviewed along with the challenges faced to lay the foundation of in-depth microalgae-bacteria biotechnology. The yield of biohydrogen produced and the lipid content of the obtained biomass can be greatly improved through the cultivation of a microalgae-bacteria consortium compared to the pure culture of microalgae. The consumption of nutrients in wastewater by the microalgae-bacteria consortium protects the environment as the effluent returned to nature is of minimum toxicity. The symbiotic relationship between microalgae and bacteria has enhanced the lipid productivity of biomass in previous studies. In contrast to other recent reviews, the linkage of the circular economy with the microalgae-bacteria consortium was critically reviewed and discussed. Uncertainties under culturing conditions and techno-economics are the concerns and factors that impede the development of microalgae-bacteria consortia in energy commercialization.