The biofilm returns: microbial life at the interface

Scientific studies over the past few decades have shown that the vast majority of microbes in the aqueous environment do not live as free-floating (i.e., planktonic) forms, but rather prefer to live as attached communities termed biofilms. Biofilm formation onto surfaces is usually detrimental to human health and man-made structures; biofilm-related problems range from antibiotic-resistant infections in humans and animals to drinking water contamination, energy loss in industrial systems, and increased corrosion in ship hulls and offshore structures. Biofilms also play several beneficial roles, such as nutrient transformation in the plant rhizosphere and enhanced biodegradation of organic carbon and various pollutants during wastewater treatment and soil bioremediation. Recently, biofilms have shown great potential in selective, low-cost catalysis and energy conversion processes in biofuel production and microbially driven batteries. The biofilm structure provides several advantages to microorganisms within the biofilm, including resistance to biocides and antibiotics, viscoelasticity, and resistance against fluid-dynamic shear stress. The congregation of multiple species into biofilm microcosms increases the range of substrates that can be biodegraded and offers great flexibility for a number of biotechnological applications. In the last 20 years, researchers have unveiled the relationship between biofilm structure and activity and have devised many methods to control biofilm development. However, use of biofilms for contaminant degradation in the field is still in its infancy. Furthermore, the processes that employ biofilms for energy conversion, environmental sensing, and white biotechnology (commonly known as industrial biotechnology) are still largely confined to academic research. In this chapter, we aim to highlight the most important and recent advances in the field of biofilm-based technologies and their potential applications.