The rise in living standards has generated a demand for higher aquatic environmental quality. The microalgal community and the surrounding organic molecules, environmental factors, and microorganisms, such as bacteria, are together defined as the phycosphere. The bacteria in the phycosphere can form consortia with microalgae through various forms of interaction. The study of the species in these consortia and their relative proportions is of great significance in determining the species and strains of stable algae that can be used in sewage treatment. This article summarizes the following topics: the interactions between microalgae and bacteria that are required to establish consortia; how symbiosis between algae and bacteria is established; microalgal competition with bacteria through inhibition and anti‐inhibition strategies; the influence of environmental factors on microalgal–bacterial aggregates, such as illumination conditions, pH, dissolved oxygen, temperature, and nutrient levels; the application of algal–bacterial aggregates to enhance biomass production and nutrient reuse; and techniques for studying the community structure and interactions of algal–bacterial consortia, such as microscopy, flow cytometry, and omics. Practitioner points Community structures in microalgal–bacterial consortia in wastewater treatment. Interactions between algae and bacteria in wastewater treatment. Effects of ecological factors on the algal–bacterial community in wastewater treatment. Economically recycling resources from algal–bacterial consortia based on wastewater. Technologies for studying microalgal–bacterial consortia in wastewater treatment.

Microalgal-bacterial consortium is an effective way to meet increasingly stringent standards in wastewater treatment. However, the mechanism of wastewater removal effect has not been properly explained in community structure by phycosphere. And little is known about that the concept of macroecology was introduced into phycosphere to explain the phenomenon. In the study, the algal–bacterial consortia with different ratios of algae and sludge were cultured in same aerobic wastewater within 48 h in photobioreactors (PSBRs). Community structure at start and end was texted by metagenomic analysis. Bray–Curtis similarities analysis based on microbial community showed that there was obvious convergent succession in all consortia, which is well known as “convergence” in macroecology. The result showed that Bray–Curtis similarities at End (overall above 0.88) were higher than these at Start (almost less than 0.66). In terms of community structure, the consortium with 5:1 ratio at Start are the more similar with the consortia at End by which the maximum removal of total dissolved nitrogen (TDN, 73.69%), total dissolved phosphorus (TDP, 94.40%) and NH3-N (93.26%) in wastewater treatment process and biomass production (98.2%) higher than other consortia, according with climax community in macroecology with the highest resource utilization than other communities. Therefore, the macroecology can be introduced into phycosphere to explain the consortium for advanced wastewater treatment and optimization community structure. And the study revealed a novel insight into treatment effect and community structure of algal–bacterial consortia for advanced wastewater treatment, a new idea for to shortening the culture time of consortium and optimize predicting their ecological community structure and predicting ecological community.

The performance of microalgal–bacterial consortia in wastewater treatment and biomass production needs to be further optimized to meet increasingly stringent effluent standards and operating costs. Besides, due to uncontrollability of ambient conditions, it is generally believed that operating conditions (e.g., aeration) respond to ambient conditions (e.g., illumination). Therefore, response surface methodology (RSM) based on Box–Behnken design was used in this study to analyze the removal of chemical oxygen demand (COD), NH3‐N and TP, and algal biomass of the microalgal–bacterial consortia within 48 h. The results showed that under medium illumination intensity (5000 lx), photoperiod (12:12) and aeration rate (0.55 L min −1), the removal efficiency of COD, NH3‐N and TP was the highest, and the maximal biomass growth rates were 95.43%, 95.49%, 89.42% and 99.63%, respectively. However, as the limited critical removal requirements of TP, the effluent standards can only be achieved within the small illumination intensity and photoperiod available range, even under medium aeration conditions, which means that under fixed operating conditions, the effective operation range will be very limited. In addition, based on RSM and differential equation analysis, the further study indicated that the effective treatment range can be greatly expanded within aeration responding, which meets the discharge standard of pollutants in China. Practitioner points Illumination was responded by aeration for optimizing performance of microalgal–bacterial consortium for wastewater treatment and biomass productivity. The strategy of optimization was based on response surface methodology. The maximum effect on wastewater treatment and biomass productivity was based on partial differential equations and quadratic inhomogeneous equations. Limited to critical TP‐removal requirements, effluent standards can meet only in the small‐usable range of illumination, under medium aeration.

With the development of life and industry, the nutrients in sewage increased gradually. The emerging symbiotic system of algal and bacteria has remarkable effect in removing nutrients such as nitrogen and phosphorus. In this paper, the influence of nitrogen and phosphorus on bacteria-algal consortia and the absorption mechanism of nitrogen and phosphorus by the interaction of bacteria-algal consortia were analyzed, and a variety of methods for studying bacteria-algal consortia were summarized, mainly using isotope tracer technology to study the research results of bacteria and algae absorbing nitrogen and phosphorus in water. This method is of great significance for analyzing the mechanism of the treatment of nitrogen and phosphorus by the bacterial-algal symbiosis system from the microscopic point of view.