Biodegradation of keratins and phenolic compounds

This dissertation consists of two parts. Part I of this study deals with the biodegradation of keratinaceous material by dermatophytic fungi. The second part describes the research from the study of the adaption of a heterogenous culture to the biodegradation of phenolic compounds.; In the keratin degradation studies, keratin degrading enzymes from naturally occurring microorganisms were isolated. The capacity of the isolated enzymes as well as the organisms were measured for their effectiveness as keratin degraders. Initially nine fungi reported to have keratinolytic activity were purchased from ATCC. Additional microorganisms were enriched from natural sources. The optimum growth conditions of the fungal cultures were determined by cultivation on a medium containing keratin as the sole source of carbon. Maximum keratinase production peaked after 10 days of growth if spores were used as the inoculum. Keratinolytic activity was determined by a Keratin Azure enzyme assay using the spectrophotometric measurement of dye released from wool.; An extracellular keratinase was isolated from Paecilomyces lilacinus. The molecular weight was determined and an amino acid analysis of the enzyme was performed.; In part II of this study, the enhanced biodegradation of phenolic compounds in activated sludge was investigated. Cultures were adapted to phenolic degradation by preexposure to fatty acid phenyl esters. Adaption was determined as a change in the rate of biodegradation of the phenolic compound compared to unexposed cultures. The rate of biodegradation was measured by monitoring the CO{dollar}sb2{dollar} evolution of the culture.; Using activated sludge, oleic acid phenyl ester preexposed cultures adapted to phenol degradation after one day of lag phase while the unexposed cultures required more than 7 days to adapt to phenol degradation. In experiments with chlorinated phenols, similar results were observed. The adapted cultures degraded the chlorinated phenols but at lower rates than cultures adapted to phenol degradation. Unexposed cultures did not degrade chlorinated phenols.; Cellular fatty acid profiles of the degrading cultures and phenol hydroxylase activity data were obtained in an attempt to understand the mechanism of enhanced. The results suggested that an increase in the degradative population occurred along with the natural population adapting to the toxic effects of phenol.