Single cell protein production by a local Aspergillus niger in solid state fermentation using rice straw pulp as carbon source: effects of fermentation variables

Abstract In this study, solid-state fermentation was carried out to produce single cell protein by local Aspergillus niger. Rice straw pulp produced from the pretreatment by liquid hot water at temperature 121 °C for 60 minutes of cooking time was used as carbon source. The effects of nitrogen sources, initial medium pH, C/N ratios of substrates and fermentation time on SCP production were evaluated in these experiments. The single cell protein was measured as crude protein content in the fermentation product by the Kjeldahl analysis method. The maximum crude protein of 18.9 % (w/w) contained in the fermentation product occurred at the fermentation condition with C/N ratio 30:1, the initial medium pH 4, temperature 30 °C, moisture content 75 % and relative humidity 95 %.