Biodegradation by cells encapsulated in silica gel is an economical and environmentally friendly methodfor the removal of toxic chemicals from the environment. In this work, recombinant E. coli expressing atrazine chlorohydrolase (AtzA) were encapsulated in organically modified silica (ORMOSIL) gels com-posed of TEOS, silica nanoparticles (SNPs), and either phenyltriethoxysilane (PTES) or methyltriethoxysi-lane (MTES). ORMOSIL gels adsorbed much higher amounts of atrazine than the hydrophilic TEOS gels. This study showed for the first time that optimized hydrophobic gel material design can be used to enhance both removal and biodegradation of hydrophobic chemicals.