Application of microalgae-bacteria symbiosis system in wastewater treatment

Abstract:

Microalgae play a key role in diverse marine ecosystem, and they also naturally coexist with a large variety of other microorganisms. In this symbiosis, O₂ released by algal photosynthesis is utilized by aerobicheterotrophic bacteria to mineralize organic compounds, and bacterial respiration provides CO₂ as a carbon source to algae. The algae-bacteria consortia has been extensively studied for applications in wastewater treatment. The algae-bacteria interactions and the application of microalgae-bacteria symbiosis system in wastewater treatment were summarized. According to previous studies, algae-bacteria interactions are categorized into nutrient exchange, signal transduction and gene transfer. The treatment of wastewater, contaminated by nutrients, heavy metals, crude oil, polycyclic aromatic hydrocarbons, and pharmaceutical contaminants through microalgae-bacteria symbiosis system was reviewed. Assimilation, anaerobic ammonia oxidation, nitrification and denitrification, phosphorylation are key mechanisms during inorganic nitrogen and phosphorus removal. The removal mechanisms of heavy metals, crude oil, polycyclic aromatic hydrocarbons, and pharmaceutical contaminants by microalgae-bacteria symbiosis system include bioadsorption, bioaccumulation, and intracellular and extracellular biodegradation.