DEVELOPMENT AND APPLICATION OF BACTERIAL CULTURES FOR THE REMOVAL OF CHLORINATED ALIPHATICS

The possibility of obtaining microbial cultures for the degradation of halogenated aliphatic hydrocarbons is mainly determined by the divers ity and activity of catabolic enzymes that exist in nature. If a suita ble organism is available, applications for the treatment of different waste streams can be developed. The relation between the kinetic para meters of the key enzymes and the properties of the organisms relevant for such applications is discussed, both for growth supporting and co metabolic degradation. When growth on a chlorinated aliphatic compound is possible, development of a biological remediation process is likel y to be relatively easy. This is illustrated with the degradation of 1 ,2-dichloroethane, a synthetic compound that can be mineralized by spe cific cultures. Closely related compounds may be recalcitrant, which c an be understood from an examination of the degradative pathways. The development of biological treatment processes based on cometabolic deg radation is more demanding because selection of the proper organisms a nd maintaining them in the process are not straightforward. The range of compounds that can be degraded cometabolically is significantly lar ger. The potential of obtaining improved degradation by genetic adapta tion and the use of biofilms is discussed.