Recent advances in microbial biotechnology for wastewater treatment

Wastewater treatment plays a pivotal role in environmental protection and sustainable development, but traditional biological treatments have drawbacks when treating complex wastewater streams that contain mixed organic contaminants, nutrients, heavy metals, and emerging contaminants. The new trends in environmental biotechnology have offered novel approaches to enhance treatment process efficiency, improve system durability, and increase resource recovery. This review critically evaluates the advances made in the context of the global environment in the area of biotechnology for wastewater treatment, with a particular emphasis on analyzing microbial innovations, genetic and synthetic biology methods, advanced bioreactor design, and novel hybrid systems. The progress in engineered microbial consortia, bioaugmentation, and metabolic pathway engineering is described, and the increased use of CRISPR-based technologies and synthetic biology to enhance pollutant degradation and optimize the process is discussed. The developments in membrane bioreactors, bioelectrochemical systems, and integrated biological physicochemical processes are evaluated in terms of their performance for treatment, energy recovery, and scalability. The specific focus is on the biotechnological elimination of newly emerging contaminants, such as pharmaceuticals, microplastics, and per- and polyfluoroalkyl substances, which are not yet well addressed by conventional treatment systems. Although considerable advances have been made in the laboratory and on pilot scales, notable research gaps remain that would prevent application in practical settings, such as the lack of field-scale validation and insufficient understanding of long-term microbial stability under varied conditions.