Isolation and screening of Aspergillus niger OM51038 from agrowastes dumpsite for citric acid production

Abstract

Citric acid is a weak organic acid occurring naturally in all citrus fruits. It has wide industrial applications in chemical, cosmetics, pharmaceutical, food and beverages industries. This study was aimed at isolating and screening Aspergillus niger from agro-waste (sugarcane bagasse, corncob, plantain trunk and groundnut shell) dumpsite for citric acid production. The soil sample from agro-waste dumpsites wasserially diluted and plated on potatoe dextrose agar. The isolates were screened for their potential to produce citric acid by plating on Czapek dox medium. The agro-wastes were pretreated and hydrolyzed. The reducing sugar obtained after hydrolysis was used to compound czapek dox broth for citric acid production. The fungal growth and citric acid production were determined using spectrometry. Aspergillus niger OM510398 was isolated from the agro-waste dumpsite. The pretreated and hydrolyzed agro wasteproduced 21.45, 22.96, 21.86 and 11.52 mg/ml of reducing sugar. The fungal growth was 0.9392, 1.1536, 3.0705 and 1.3736 after 72 h andcitric acid produced was1.4672, 1.6202, 3.8030 and 1.9023for sugarcane bagasse, corncob, plantain trunk and groundnut shell respectively, Thus, plantain trunk was the best agro-waste for citric acid production by Aspergillus niger OM510398 and can be applied for industrial use.