The next phase of the research planned by Liu and colleagues will involve isolating and identifying natural biofilm-forming isolates with increased ability to colonize and form biofilms on microplastics, moving the proof-of-concept from the lab to an ecological setting.
However, there is another issue involving microplastic and biofilm.
Dung Ngoc Pham and the team at the New Jersey Institute of Technology have shown that microplastics can become ‘hubs’ for antibiotic-resistant bacteria and pathogens to grow in the form of biofilm once they enter the WWTP. This biofilm allows pathogenic microorganisms and antibiotic waste to attach and interact. In findings published in Elsevier’s Journal of Hazardous Materials Letters, researchers found that specific genes known to play a role in antibiotic resistance were up to 30 times higher while living as a biofilm on microplastic. They also found eight different species of bacteria enriched on microplastic, out of which two were emerging pathogens typically linked to respiratory diseases. Bacteria Novosphingobium pokkalii, which is being further studied, was a key initiator in forming the sticky biofilm that attracts such pathogens. Such pathogenic biofilm associated with microplastic can allow them to survive disinfection processes and cause a health hazard along with significantly increasing treatment costs.
Both microplastics and antimicrobial resistance biofilms are a nuisance to the environment and human health. The above two research could suggest a new outlook for solving both these problems in WWTP. Understanding antimicrobial resistance and the microorganism responsible for biofilm development will further help develop a “capture and release” mechanism for microplastic capture, which would in turn help to immobilize pathogenic biofilm.
Specific biofilm “on” and “off” genetic controls could be designed by further understanding the developmental process leading to biofilm formation. The “on” switch can trigger capture genes in microbes to form a biofilm on the microplastic, aggregating them in a specific chamber. The “off” gene could release microplastic from the biofilm, both of which could be treated independently.