Influence of peptone, ammonia water and urea supplements on keratinolytic and associated non-keratinolytic fungi in sewage sludge

A hair-baiting method was used in laboratory study of the influence on the composition of the keratinolytic and non-keratinolytic mycobiota in sewage of adding the ammonium nitrogen sources, peptone, ammonia water and urea. It was demonstrated that, independent of the nitrogen source, the ammonium nitrogen concentration was the critical factor affecting the fungal composition. Ammonium prevented or markedly inhibited the growth of Trichophyton terrestre, with its teleomorph Arthroderma quadrifidum; other geophilic dermatophytes and non-keratinolytic fungi. It also favoured growth of Chrysosporium keratinophilum and some other species, mainly in the genus Chrysosporium. The composition of the keratinolytic mycobiota can be an indicator of sludge organic matter stabilization, and used in relation to sewage sludge at wastewater treatment plants and in reclamation practice.