HPLC based characterization of citric acid produced from indigenous fungal strain through single and Co-Culture fermentation

Abstract Agro-based waste materials are primarily composed of complex polysaccharides that strengthen microbial growth to produce industrially relevant value-added products. Therefore, in the present study, solid state fermentation (SSF) was carried out using peanut shell, orange peel and mixture of both with 50:50 ratio as support for SSF to enhance citric acid production from single and co-culture consortia of Rhizopus stolonifera and Aspergillus niger. During initial trial, it was observed that growth media supplemented with orange peel under solid state fermentation (SSF) process of co-culture consortia revealed high yield (1593 μg/mL) of citric acid. On partial optimization of co-culture showed the maximum citric acid yields (7651 μg/mL) in the presence of orange peel base medium at 50% moisture content, 30 °C temperature, 5.5 pH and 25 g substrate concentration after 48th hours of solid-state fermentation. This amount of citric acid produced in the culture was estimated through reversed-phase High Performance Liquid Chromatography (HPLC) technique. Recent research activity revealed that a suitable addition of fermentative substrate to the solid-state fermentation media increased fungal growth, sugar utilization and citric acid production when used in lower concentration.