Production of protein rich organic fertilizer from fish scale by a mutant <i style="">Aspergillus niger</i> AB₁₀₀^__ A media optimization study

Abstract

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Fish scale, the chief waste material of fish processing industries, was enzymatically hydrolyzed by protease of <i style="">Aspergillus niger</i> AB₁₀₀ to produce soluble protein for use as organic fertilizer. Optimum inorganic nutrients were found to be: MgSO₄, 0.75; K₂HPO₄, 0.2; and KCl, 0.075%. <i style="">A. niger</i> AB₁₀₀required FeSO₄.7H₂O (5 μg/ml) and ZnSO₄.7H₂O (15 μg/ml) for higher amount of protease production and yield. The optimum values for the tested cost-effective nutrients for the maximum protease production were: Defatted soybean-meal, 0.2; Peptone, 0.3; and Corn-steep-liquor, 0.2%. Biomass growth was not related proportionately in every case with that of enzyme production and protein solubilisation but protease production shows a positive correlation with hydrolysis of scale to produce soluble protein. </smarttagtype></smarttagtype>