Growth, keratinolytic proteinase activity and thermotolerance of dermatophytes associated with alopecia in Uyo, Nigeria

Mycological research was conducted on the mycelial growth, keratinolytic proteinase activity and thermotolerance of dermatophytes associated with alopecia patients in Uyo, Nigeria. The results revealed that Microsporum sp. — AP1 , Epidermophyton sp. — AP2 , Trichophyton rubrum — AP4 , Trichophyton mentagrophytes — AP5 and a yeast Candida albicans — AP3 isolated exhibited variable growth and keratinase activity at different temperatures. Microsporum sp. — AP1 and T. mentagrophytes — AP5 survived heat treatment at 90 °C but exhibited best mycelial growth at 30 °C (with 53.41 mg/50 ml biomass dry weight) and 40 °C (with 61.32 mg/50 ml biomass dry weight) respectively, after incubation for 2 weeks. Trichophyton rubrum — AP4 and Epidermophyton sp. — AP2 could not survive heat treatment at 90 °C but grew better at 40 °C (with 38.52 mg/50 ml biomass dry weight) and 30 °C (with 48.32 mg/50 ml biomass dry weight) respectively, over the same incubation period, while C. albicans — AP3 grew better at 30 °C with 38.7 mg/50 ml biomass dry weight after 2 weeks, but failed to survive at 70 °C. All the isolates except Candida albicans — AP3 survived at 80 °C and exhibited great potential to elaborate keratinolytic enzymes, with T. mentagrophytes demonstrating the best potential at 30 °C and 40 °C. Higher temperatures tended to reduce keratinolytic activities and there were significant (P