DETERMINING THE OPTIMUM OPERATING CONDITIONS FOR ENHANCING CITRIC ACID YIELD USING RESPONSE SURFACE METHODOLOGY

• Main Author: Rizka Widyanti, Allysa
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81975
• Institution: Institut Teknologi Bandung

Citric acid is one of the important commodities widely applied in industries such as food, pharmaceuticals, and cleaning agents. Commercial production of citric acid is still dominated by submerged fermentation methods, but solid-state fermentation shows greater potential, including higher citric acid yield, lower energy requirements, and the utilization of agro-industrial waste as substrates. The aim of this study is to determine the best operating conditions to enhance citric acid yield in solid-state fermentation using Response Surface Methodology (RSM). The solid-state fermentation was carried out using cassava bagasse, which contains 81,67% starch, and biocatalyst Aspergillus niger. In this study, a three-level, four-variable design of RSM comprising 26 experimental runs was conducted in duplicate. The experiments were used to develop a statistical model that can generate optimum operating conditions, including methanol concentration, amount of medium, glucose concentration, and fermentation time. The evaluation of optimum conditions for citric acid production was conducted using the RSM, Central Composite Design (CCD) method. The results of the ANOVA analysis indicated that four factors significantly affected citric acid yield: the amount of medium, methanol concentration, the quadratic term of fermentation time, and the interaction between the amount of medium and methanol addition. The interaction between operating condition factors is displayed in the surface plot. Optimization results using Minitab indicated that the operating conditions of 13 mL medium, 0,5% methanol concentration, and 8 days of fermentation could yield 7,21 mg/g substrate of citric acid.