Living biofouling-resistant membranes as a model for the beneficial use of engineered biofilms

Abstract

Membrane systems are used increasingly for water treatment, recycling water from wastewater, during food processing, and energy production. They thus are a key technology to ensure water, energy, and food sustainability. However, biofouling, the build-up of microbes and their polymeric matrix, clogs these systems and reduces their efficiency. Realizing that a microbial film is inevitable, we engineered a beneficial biofilm that prevents membrane biofouling, limiting its own thickness by sensing the number of its cells that are present via a quorum-sensing circuit. The beneficial biofilm also prevents biofilm formation by deleterious bacteria by secreting nitric oxide, a general biofilm dispersal agent, as demonstrated by both short-term dead-end filtration and long-term cross-flow filtration tests. In addition, the beneficial biofilm was engineered to produce an epoxide hydrolase so that it efficiently removes the environmental pollutant epichlorohydrin. Thus, we have created a living biofouling-resistant membrane system that simultaneously reduces biofouling and provides a platform for biodegradation of persistent organic pollutants.

Combat biofilm by bacteriostatic aptamer‐functionalized graphene oxide

“…All DNA oligonucleotides, 2‐( N ‐morpholino) ethanesulfonic acid (MES), 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide hydrochloride (EDC), N ‐hydroxysulfosuccinimide (NHS), sterile tissue culture plates (six‐well and 96‐well plates) were purchased from Sangon Biotech Co., Ltd. (Shanghai, People's Republic of China). Serovar typhimurium (CMCC 50115) and S. choleraesui (ATCC 10708) were kindly provided by the Changsha Central Hospital (Changsha, People's Republic of China), and P. aeruginosa (ATCC 27853) and Staphylococcus epidermidis (RP62A) were provided by The Third Xiangya Hospital of Central South University (Changsha, People's Republic of China); all of those bacterial strains are selected for this work because they are the most frequently detected deleterious bacteria on sepsis and biofouling . All chemicals in this experiment were of analytical grade.…”

Membrane Bioreactor (MBR) Technology for Wastewater Treatment and Reclamation: Membrane Fouling

“…Additionally, recently, Wood et al [ 180 ] engineered a beneficial biofilm that mitigates biofouling (through limiting its own thickness) by sensing the number of its cells that are present via a QS circuit. This was based on the secretion and uptake of a communication signal; hence, biofilm formation was limited by self-monitoring and selective dispersal.…”

Importance of the biofilm matrix for the erosion stability of Bacillus subtilis NCIB 3610 biofilms

“…The production and secretion of extracellular polymeric substances (EPS) by biolm forming bacteria provides the bio-lm forming community with new emergent properties: 1 the bacteria are embedded within these exopolymers (the biolm matrix), the resulting clusters protect them from the environment, antibiotics 2,3 and other chemicals, 4 and the structural rigidity provided by the biolm matrix enables the community to withstand high shear forces or other mechanical stresses 5 and governs invasion resistance. 6 Although biolm formation can be benecial for industrial applications, 7,8 biolms growing on heart valves or medical implants cause serious infections and device failure. 9,10 The biolm matrix can be composed of different exopolymeric substances such as proteins, polysaccharides, DNA or lipids.…”