Production of Citric Acid from Solid State Fermentation of Sugarcane Waste using Aspergillus Niger and Indigenous Sugarcane Microflora

Aspergillus niger is the leading microorganism of choice for citric acid production. Sugarcane waste was used as substrate under solid state fermentation to comparatively evaluate the citric acid production capacity of Aspergillus niger isolates and the indigenous microflora in the sugarcane waste. Known optimal cultural parameters such as moisture content, particle size and sugar level were used. Aspergillus niger produced 30.54 g/L citric acid while the indigenous microflora produced 28.93 g/L citric acid after fermentation at 30°C for 8 days. The residual sugar concentration decreased from 11.35 g/L to 3.14 g/L in the Aspergillus niger fermentation medium and from 10.67 g/L to 5.99 g/L in the indigenous microflora fermentation medium.  Keywords : Citric acid production; sugarcane waste; indigenous micro flora; fungus-specific fermentation extract