Several major diseases of old age, including atherosclerosis, macular degeneration, and neurodegenerative diseases, are associated with the intracellular accumulation of substances that impair cellular function and viability. A radically new approach is to augment humans' natural catabolic machinery with microbial enzymes, since natural environments contain microorganisms with a wide range of biodegradation capabilities. Completely biodegrading complex organic materials demands many steps of hydrolysis and oxidation. Microbial communities exhibit diversity because they sometimes require several different microorganisms to carry out all the steps and they often have metabolic redundancy, i.e., several microorganisms able to carry out the same steps using different versions of the same kind of enzyme.
Although the principles underlying bioremediation are relatively well understood today, the strains responsible for degradation of aggregates associated with aging have not been identified. Once capable strains are identified and isolated, their biodegradative enzymes can be studied for potential use in medical therapies. Fortunately, identification and isolation are becoming more tractable today through the development of molecular techniques that directly target the cells' DNA and RNA. Many new methods are being developed each year, and two approaches are especially noteworthy in this context: molecular fingerprinting and the DNA microarray. Molecular fingerprinting relies on the fact that the sequences of genes that code for like protein products are usually similar. In that case, a primer can be generated for a class of genes. We can separate the different amplified products by electrophoresis to create a DNA fingerprint, and we can track the emergence of important community members or important genes even when we do not know the identity of the microorganism. DNA-microarray technology is an emerging tool. Arrays of hundreds to thousands of oligonucleotides from well-characterized or partially characterized strains allow us to track the presence of many interesting microorganisms, genes, and gene expression with one assay.