Implications of Growth and Starvation Conditions in Bacterial Adhesion and Transport

Abstract

Biofouling is synonymous with unwanted biofilms and leads to problems ranging from efficiency and resource loss to health risks. While a number of bacterial properties including biomass concentration and hydrophobicity are considered critical to biofilm development and bacterial adhesion, the variations in these properties under growth and starvation conditions are not very well known. Here, we describe the trends in these properties for four Gram-negative bacteria under growth and extended starvation conditions. A convenient and frequently-used laboratory assay, the microbial adhesion to hydrocarbons (MATH) test, was used to determine the microbial hydrophobicity based on the partitioning of cells at an aqueous-hydrocarbon interface. The bacteria tested exhibited a plateau in hydrophobicity values during the stationary growth phase and longer starvation durations ( 10 days). Starved cultures had higher hydrophobicity and lower cell sizes than growth cultures. Interestingly, hydrocarbon exposure led to an increase in cell size for starved cells as compared to control cultures, while cells under growth conditions did not show significant size changes due to hydrocarbon presence. Cells starved for short durations (up to 7-10 days) exhibited significant variations in microbial hydrophobicity, cell size, and biomass concentration (total proteins and optical density). These results show the importance of studying the bacterial properties as a function of growth and starvation phase for cell adhesion in the context of biofilm formation and biofouling.

Diverse effects of a biosurfactant from Rhodococcus ruber IEGM 231 on the adhesion of resting and growing bacteria to polystyrene

“…As seen from Table 3 , exponentially growing cells of four strains from the total seven showed an increase in their hydrophobicity compared to stationary phase cultures. Previous studies have also reported higher hydrophobicity of bacteria in the exponential phase (Loosdrecht et al 1987 ; Heise and Gust 1999 ; Jana et al 2000 ; Khemakhem et al 2005 ; Gargiulo et al 2007 ; Saini et al 2011 ), while an opposite trend, i.e. hydrophobicity increase with the cell age was observed by other researchers (Allison et al 1990 ; Nejidat et al 2004 ; Walker et al 2005 ; Zikmanis et al 2007 ).…”

Life under extreme energy limitation: a synthesis of laboratory- and field-based investigations

“…Consistent with this notion, numerous microbial strains increase surface adhesion under energy limitation in laboratory experiments. The Gram-negative E. coli and Shewanella oneidensis trigger adhesion by increasing hydrophobicity of their outer cell membranes (Saini, Nasholm and Wood 2011). Vibrio sp.…”