Biofilm detachment by self-collapsing air microbubbles: a potential chemical-free cleaning technology for membrane biofouling

Microbubbles (MBs) have been known for their ability to generate pressure waves through shrinking and subsequent self-collapsing phenomenon. In the present study, we have investigated the potential of air MBs for biofilm detachment from a nylon membrane surface in comparison to chemical cleaning by sodium hypochloride (NaOCl). About 88% of fixed biomass detachment was observed after 1 h air microbubbling, while only 10% of biofilm detachment was achieved in the control experiment without microbubbles. Images taken with a confocal laser scanning microscope (CLSM) clearly showed that nearly all extracellular polysaccharides and proteins in biofilms were removed from the membrane surface, indicating a complete disruption of the extracellular polymeric matrix of biofilms. It was further demonstrated that microbubbling is much more efficient than chemical cleaning with 0.5% NaOCl solution in terms of removal of fixed biomass and extracellular polysaccharides and proteins. This study provides experimental evidence showing that self-collapsing air MBs is a chemical-free and eco-friendly technology for biofilm detachment.

[1]  Claus-Dieter Ohl,et al.  Surface cleaning from laser-induced cavitation bubbles , 2006 .

[2]  Pierre Le-Clech,et al.  Fouling in membrane bioreactors used in wastewater treatment , 2006 .

[3]  D. Bagley,et al.  A Review of Biofouling and its Control in Membrane Separation Bioreactors , 2004, Water environment research : a research publication of the Water Environment Federation.

[4]  F. Smith,et al.  COLORIMETRIC METHOD FOR DETER-MINATION OF SUGAR AND RELATED SUBSTANCE , 1956 .

[5]  T. Murakami,et al.  Ozone micro-bubble disinfection method for wastewater reuse system. , 2007, Water science and technology : a journal of the International Association on Water Pollution Research.

[6]  Kenji Kurata,et al.  Application of Microbubbles to Hydroponics Solution Promotes Lettuce Growth , 2009, HortTechnology.

[7]  P. Watnick,et al.  Signals, Regulatory Networks, and Materials That Build and Break Bacterial Biofilms , 2009, Microbiology and Molecular Biology Reviews.

[8]  J. Bull.  The application of microbubbles for targeted drug delivery , 2007, Expert opinion on drug delivery.

[9]  H. Stone,et al.  Interfacial Polygonal Nanopatterning of Stable Microbubbles , 2008, Science.

[10]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[11]  G. Bartsch,et al.  Detection of prostate cancer with a microbubble ultrasound contrast agent , 2001, The Lancet.

[12]  Ashutosh Agarwal,et al.  Principle and applications of microbubble and nanobubble technology for water treatment. , 2011, Chemosphere.

[13]  Masayoshi Takahashi,et al.  Effect of Shrinking Microbubble on Gas Hydrate Formation , 2003 .

[14]  Eleanor Stride,et al.  Novel microbubble preparation technologies , 2008 .

[15]  Allison M. Horst,et al.  Enhanced visualization of microbial biofilms by staining and environmental scanning electron microscopy. , 2007, Journal of microbiological methods.

[16]  K. Tachibana,et al.  Albumin microbubble echo-contrast material as an enhancer for ultrasound accelerated thrombolysis. , 1995, Circulation.

[17]  Jonathan R. Lindner,et al.  Microbubbles in medical imaging: current applications and future directions , 2004, Nature Reviews Drug Discovery.

[18]  H. Furumai,et al.  Yields of Biomass and Extracellular Polymers in Four Anaerobic Sludges , 1996 .

[19]  H. Flemming,et al.  Ultrasound as a means of detaching biofilms , 1990 .

[20]  Cell detachment method using shock-wave-induced cavitation. , 2003, Ultrasound in medicine & biology.

[21]  H. Flemming,et al.  The biofilm matrix , 2010, Nature Reviews Microbiology.

[22]  Niek N. Sanders,et al.  Drug loaded microbubble design for ultrasound triggered delivery , 2009 .

[23]  C. Ohl,et al.  Detachment and sonoporation of adherent HeLa-cells by shock wave-induced cavitation. , 2003, Biochimica et biophysica acta.

[24]  L. Y. Dudley,et al.  Biofouling in membrane systems — A review☆ , 1998 .

[25]  N. Mase,et al.  Aerobic copper/TEMPO-catalyzed oxidation of primary alcohols to aldehydes using a microbubble strategy to increase gas concentration in liquid phase reactions. , 2011, Chemical communications.

[26]  Koichi Terasaka,et al.  Development of microbubble aerator for waste water treatment using aerobic activated sludge , 2011 .

[27]  P. Zhong,et al.  Pulsating tandem microbubble for localized and directional single-cell membrane poration. , 2010, Physical review letters.