Twenty fungal strains belonging to 17 species and isolated from male scalp hair were tested for their capacity to hydrolyze keratinous material from chicken feather. The identification of the three most efficient species was confirmed by sequencing of the internal transcribed spacer (ITS) region of rDNA. Activities of fungal keratinases produced by Aspergillus stelliformis (strain AUMC 10920), A. sydowii (AUMC 10935), and Fusarium brachygibbosum (AUMC 10937) were 113, 120, and 130 IU mg⁻¹ enzymes, respectively. The most favorable conditions were at pH 8.0 and 50 °C. Keratinase activity was markedly inhibited by EDTA and metal ions Ca⁺², Co⁺², Ni⁺², Cu⁺², Fe⁺², Mg⁺², and Zn⁺², with differences between the fungal species. To the best of our knowledge, this is the first study on the activity of keratinase produced by A. stelliformis, A. sydowii, and F. brachygibbosum. F. brachygibbosum keratinase was the most active, but the species is not recommended because of its known phytopathogenicty. Aspergillus sydowii has many known biotechnological solutions and here we add another application of the species, as producer of keratinases. We introduce A. stelliformis as new producer of active fungal keratinases for biotechnological solutions, such as in the management of keratinous waste in poultry industry.

A taxonomic revision of the genus Amaranthus (Amaranthaceae) in Saudi Arabia, based on both field surveys and examination of harbarium specimens, is here presented. Collected exsiccata are kept the Herbaria PNUH and RO. An extensive literature was also analysed. Sixtheen non-hybrid taxa (twelve species) are recognized. Data about nomenclature (accepted names, main synonyms, and types), morphology, chromosome number, chorology (for native taxa) or alien status (for exotic taxa), occurrence in Saudi Arabia, ecology (preferential habitat, phenology, elevation), and taxonomic annotations are provided for each taxon. A diagnostic key is proposed. Four taxa (A. graecizans subsp. graecizans, A. graecizans subsp. sylvestris, A. graecizans subsp. thellungianus, and A. sparganicephalus) are native, whereas the other ones are to be considered aliens. A. dubius and A. blitoides var. blitoides are new for the national flora. Furthermore, the name A. sparganicephalus is neotypified on a specimen deposited at E and a nomenclatural change (A. blitum var. nanus comb. nov.) is proposed.