Scale-up of citric acid production by utilizing rice husk waste and purification using ion exchange chromatography

Abstract

Citric acid is one of the essential organic acids in human life and rice husk has the potential to be used as a substrate because it contains about 28.6-43.3% cellulose, and its use, does not compete with human needs. This research aims to increase citric acid production by using rice husk as a substrate, with a working volume of 2000 mL. In this study, it produced citric acid using submerged fermentation and Aspergillus niger at 22.42% w/v rice husk conditions, 10% w/v sucrose, 3% v/v methanol, and 400 rpm agitation. The results showed that the citric acid pH value on day 18 of fermentation was 1.9, and the concentration of citric acid after purification was 162.667 g/L, while the concentration of citric acid before purification was 148.639 g/L. The specific growth rate of Aspergillus niger obtained was 0.0863 cells/day, and the rate of reducing sugar consumption was 0.1283 g/day. The yield of Aspergillus niger biomass produced is 1.1258 cells for each g of reducing sugar, and the yield of citric acid production is 16.8144 g for each g of cell and 18.9301 g for each g of reducing sugar.