A screening was carried out on 69 fungal strains isolated from alkaline-calcareous, neutral and alkaline-sodic soils, as well as from their associated plant material, to determine their ability to grow at alkaline pH. A total of 32 fungi were selected for their ability to produce alkaline keratinase activity in submerged shaken cultures supplemented with soybean meal (SM) and tryptone and on cow hair (CH) under solid state fermentation conditions. Although several fungal strains produced keratinolytic activity on both SM and CH, they differed in the levels detected. Among them, Aspergillus niger, Cladosporium cladosporioides, Metarrhizium anisopliae, Neurospora tetrasperma and Westerdikella dispersa were the best producers, with levels higher than 1.2 U ml -1 . Different fungal species are here reported for the first time for their ability to produce keratinolytic activity at alkaline pH.

Biological control of nematodes by fungi is a promising field of application at large scale. Nematode egg is probably the most resistant stage in the nematode life-cycle, however they are susceptible to colonization and destruction by fungal egg-parasites. Fungal extra-cellular enzymes are able to degrade the main chemical constituents of nematode eggshell and at least they are partly responsible for fungal penetration and/or digestion of the internal tissues. Paecilomyces lilacinus was reported as an ovicidal fungus of Toxocara canis eggs in vitro, a parasite of dogs causing toxocarosis. Two wild-type P. lilacinus LPSC # 876 and LPSC # 44 strains, isolated from soil in the main park in the city of La Plata and an agricultural field, respectively, in Argentina, showed antagonism onto T. canis eggs. Besides from the isolation source, both strains showed similar hydrolytic profiles activities, ovicidal effect, and grew well on chitin agar, although no chitinolytic activity was detected. Nevertheless, both strains displayed proteolytic and chitinolytic activities in liquid cultures, with maximum values at 14 days of growth. Variable enzyme activities were observed on carboxymethylcellulose and starch agars, whereas the lipolytic activity was poor in both. Percentage of infected T. canis eggs was found 65.6% and 63.2% for P. lilacinus LPSC # 876 and # 44 strains respectively. Our results a priori indicate that P. lilacinus LPSC # 876 shows suitable characteristics as a potential agent for biocontrol of T. canis.

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