Microbial adhesion to hydrocarbons (math)

Microbial adhesion at the oil:water interface has been studied since the pioneering work of Mudd & Mudd (1924) in various contexts. A decade ago, microbial adhesion to hydrocarbons (MATH) was proposed as a general test for cell‐surface hydrophobicity. Since that time, various modifications, including a kinetic approach, have been adopted in different laboratories. The MATH test has helped elucidate surface structures which promote (hydrophobins) or reduce (hydrophilins) the hydrophobic properties of the outermost cell surfaces of various microorganisms. In two Gram negative bacteria, Serratia marcescens and Acinetobacter calcoacelicus, a wide array of components differing greatly in composition, appear to influence adhesion to hydrocarbon. Many microorganisms exhibit little or no affinity for the water:hydrocarbon interface. However, addition of appropriate concentrations of cationic molecules (cetylpyridinium chloride, chlorhexidine, chitosan, poly‐L‐lysine and lysozyme) can hydrophobize microorganisms and potentiate their adhesion. Several recent observations raise the possibility that microbial adhesion to hydrocarbons is, in certain cases, cell‐concentration dependent. This may reflect the increased stabilization of hydrocarbon droplets by sufficient numbers of interacting cells.