Keratinase-producing fungi from local environmental samples of Far South Thailand and their efficiency in hydrolyzing keratinous wastes

Abstract

Samples from around BangoRana, BangoAsae, and Tanod, Narathiwat Province, Thailand were screened for keratinase-producing fungi. By using Horikoshi media and keratin (1%) agar plate, 3 isolates of fungi were shown to produce wider clear zone, and they were Aspergillus sp., Penicillin sp. and Cladosporium sp., and designated as Aspergillus KF1, Penicillin KF2 and Cladosporium KF3. Each isolate was growth in Feather Meal Medium with 37°C incubation in shaking condition. Results showed that these fungi had typical growth profile. Extracellular keratinase profile for Penicillium KF2, the keratinase release began at the late lag phase (1 U/ml), whereas those of Aspergillus KF1, and Cladosporium KF3 started at the log phase (U/ml: 3.9 and 2.9). Maximal keratinase production was observed in the fungi culture on day 4 and day 5 upon shaking incubation at 37°C. Different activities were observed in U/ml likes 70.7 for Aspergillus KF1; 83.5, Penicillium KF2; and 72.4, Cladosporium KF3. Aspergillus KF1 and Penicillin FK2 reached their maximum on day 4 (CFU/ml: 8.9 × 106 and 8.4 × 106) Cladosporium FK3 on day 5 were 8.95 × 106 CFU/ml. Keratinases were expected to be of primary metabolites, and hence best harvested at the beginning of stationary phase.