Optimization Studies on Citric Acid Fermentation Process

OPTIMIZATION STUDIES ON CITRIC ACID FERMENTATION PROCESS

A. Gowthami*, M. Mounika Krishna* and K. Anand Kishore

Department of Chemical Engineering

National Institute of Technology

Warangal-506004, A.P, India

gowthami.shadows@gmail.com

mounika.motaparthi@gmail.com

kola__nitw@yahoo.com

Abstract:

The present study reports the optimization of citri c acid fermentation process which is governed

by different physical and chemical operating process variables. Six variables were found to

influence citric acid fermentation process. Using Plackett Burman method, t hree variables were

identified as dominating variables. Determining optimum values of the variables from Univariate

search method is tedious. Hence, t he experiments to be conducted for t hree variables have been

designed by central composite design (CCD) which is one of the Response Surface methods

(RSM) and then the variables were optimized using RSM to minimize the risk involved in

Univariate search method.

Key words: Citric acid, Fermentation, Plackett Burman, Response Surface method,

Optimization.

Introduction:

Citric acid is an essential biochemical commodity. It is widely found in nature and exists as an

intermediate in the citric acid cycle produced commercially by submerged aerobic fermentation

from a wide range of carbon-containing raw materials such as molasses, Corn starch, Date syrup,

Sucrose etc. Present work uses sucrose as raw material as A. niger has got potent mycelium

bound invertase that is active at low pH and rapidly hydrolyzes sucrose [1]. Citric acid is widely

used in the food, beverage, pharmaceutical, cosmetic and other industries [2]. Citric acid

productivity can be increased by optimizing its fermentation variables: Initial sucrose

concentration, Initial pH, Stirrer speed, Fermentation time, Fermentation temperature, Oxygen

flow rate, Additives and Nutrients‟ concentratio n. Response Surface Methodology (RSM) is

employed for optimizing the title variables...