ABSTRACT
Traditional routes for coal conversion to high-grade gases and liquids usually involve coal cleaning, followed by treatment at high temperatures and pressures through a series of chemical processes and separation stages. The use of biotechnology provides alternative process routes for coal conversion and/or could provide alternative methods for coal cleaning (e.g., sulfur removal) prior to use. Biotechnology is a multidisciplinary field with its roots in the biological, chemical, and engineering sciences. In principle, biotechnology can be used to bring about either a general breakdown of the coal molecule or to achieve the selective removal of particular components within its structure. Coal is basically carbonaceous material with mineral inclusions and it is such a heterogeneous substance that microorganisms may be able to attack, degrade, or use a number of different constituents. In relation to the use of biotechnology, knowledge of the porous structure of different coals is of relevance if the organisms are sufficiently small to penetrate part of the structure.
