Part (a) — catabolism vs. anabolism.Catabolism is the enzymatic BREAKDOWN of complex organic molecules into simpler ones, an exergonic process that releases the chemical energy the cell captures (as ATP) and uses for growth and maintenance — it is the "energy-yielding" half of metabolism, and it is what most bioremediation reactions (a contaminant being degraded) actually are. Anabolism is the reverse: the enzymatic BIOSYNTHESIS of complex cellular material (proteins, nucleic acids, cell wall) from simpler precursors, an endergonic process that CONSUMES the energy catabolism releases, and is what drives biomass (new cell) production. Together, catabolism + anabolism constitute the cell's overall metabolism; a chemoheterotroph degrading a contaminant is running catabolism to fuel its own anabolism.
Part (b) — biotransformation vs. mineralization.Biotransformation is any microbially-mediated change to a compound's chemical structure — it may be partial, and the resulting metabolite can be more, less, or equally toxic/mobile than the parent compound (e.g. reductive dechlorination of PCE to the more mobile and, at some stages, more toxic vinyl chloride). Mineralization is the special, complete case of biotransformation in which the organic contaminant is fully converted to inorganic end products — CO2, H2O, and inorganic ions (Cl-, NH4+, etc.) — leaving no organic residue at all. Every mineralization is a biotransformation, but most biotransformations stop short of mineralization.
The engineering consequence of this distinction is direct: a remediation performance goal specified as "biotransformation" is satisfied by ANY structural change, while a goal specified as "mineralization" requires demonstrating complete conversion to inorganic products — typically via a stoichiometric mass balance (e.g. CO2 evolution or chloride release matching the parent compound's theoretical yield), not merely the disappearance of the parent compound from an analytical method that would not detect its metabolites.
