Influence of the carbon and nitrogen sources on keratinase production by Myrothecium verrucaria in submerged and solid state cultures

Abstract

Myrothecium verrucaria is a nondermatophytic filamentous fungus able to grow and to produce keratinase in submerged (93.0 +/- 19 U/ml) and solid state (98.8 +/- 7.9 U/ml) cultures in which poultry feather powder (PFP) is the only substrate. The purpose of the present work was to verify how different carbon and nitrogen sources can influence the production of keratinase by this fungus. Addition of carbohydrates, such as glucose and sucrose, caused only slight improvements in keratinase production, but the addition of starch caused a significant improvement (135.0 +/- 25 U/ml). The highest levels of keratinase activity, however, were obtained by supplementing the PFP cultures with cassava bagasse, 168.0 +/- 28 U/ml and 189.0 +/- 26 U/ml in submerged and solid state cultures, respectively. Contrarily, the supplementation of PFP medium with organic or inorganic nitrogen sources, such as casein, soy bean protein, gelatin, ammonium nitrate and alanine, decreased the production of keratinase in both types of cultures (around 20 U/ml), showing that the production of keratinase by M. verrucaria is repressed by nitrogen sources. The results obtained in this work suggest that the association of the two residues PFP plus cassava bagasse could be an excellent option as a cheap culture medium for the production of keratinase in submerged and solid state cultures.

Metabolism of Chicken Feathers and Concomitant Electricity Generation by Pseudomonas aeruginosa by Employing Microbial Fuel Cell (MFC)

“…Production of keratinases is usually regulated by nutritional status of growth medium. In most of the cases, it is upregulated by nutrient limitation and downregulated by nutrient availability [3]. Recent studies suggest upregulation of keratinase activity by various carbon and nitrogen sources [25].…”

“…Due to poor management of waste, the by-products of poultry industry (especially feathers) have become one of the major pollutants due to their recalcitrant nature [1,2]. About 90% of feathers consist of keratin, which is a fibrous and insoluble structural protein consisting of -helical coils joint together by disulfide linkages [3]. This structural feature enables it to resist adverse environmental conditions and degradation by proteases [4].…”

Keratinase production by Bacillus pumilus GHD in solid-state fermentation using sugar cane bagasse: optimisation of culture conditions using a Box-Behnken experimental design

“…From the results obtained it is apparent that keratinase production can occur even in the absence of keratin, suggesting that keratinase in B. pumilus GHD is a noninducible enzyme. To our knowledge, there is only one report (Da Gioppo et al 2009) using Cassava bagasse in keratinase production by Myrothecium verrucaria. This result could indicate a promising future for the use of many agricultural wastes in the production of various enzymes with important biotechnological applications.…”

Biosynthesis and Control of Keratinase in Recalcitrant Feather-Degrading Bacillus megaterium F7-1

“…Carbohydrates including glucose are known as a common catabolic repressor for a number of protease in Bacillus strains (Fisher and Sonenshein, 1991). That is, the supplementation of additional carbon source has a negative effect on the production of protease (Gioppo et al, 2009). …”