Comparative studies on the effect of organic and inorganic nitrogen supplementation of millet and sorghum pomace on the production of three industrial enzymes by <I>Aspergillus niger</I> SL.1

Abstract

Effect of nitrogen source and supplementation of millet and sorghum pomace on the production of cellulase, amylase and laccase by Aspergillus niger SL.1 was investigated using a submerged culture fermentation. The nitrogen sources (ammonium sulphate, yeast extract groundnut cake and neem seed cake) were supplemented at 5 -20% level in the pomace medium and fermentation was carried out for 72 hours. Supplementation of both millet and sorghum pomace with 10 -20% groundnut cake and also 5 -20% neem seed cake in sorghum pomace media significantly (P<0.05) recorded higher level of cellulase production than the control. Amylase production significantly (P<0.05) decreased with increase in the level of supplementation of the pomace with ammonium sulphate and yeast extract. The pomace media containing 10 -20% supplementation with groundnut cake recorded higher (P<0.05) amylase activity than the control. Sorghum pomace media significantly (P<0.05) induced higher laccase production than that of millet pomace. However, supplementation of millet pomace with ammonium sulphate and groundnut cake significantly (P<0.05) recorded higher laccase production than the control. The study revealed that nitrogen supplementation of the pomace is important and enhanced the production of the three industrial enzymes.

Optimization of amylase production by Aspergillus niger in solid-state fermentation using sugarcane bagasse as solid support material

“…Although the optimal concentrations of nitrogen and phosphorous were different for each nitrogen source used, at concentrations higher than the optimal values both the nitrogen and phosphorous sources caused inhibition of enzyme synthesis. Since the liquid medium was initially buffered at pH 6.0 in the six experiments, this inhibition could be related with the repression effect that the high concentrations of nitrogen (Abu and Ado 2004;Michelena and Castillo 1984) and phosphorous (Michelena and Castillo 1984) produced on amylase production. This repression effect has been observed before for cellulose production by Aspergillus terreus (Ali et al 1991).…”