a solid state fermentation method was used to utilize wheat straw as substrates for citric acid production by using aspergillus niger atcc 9142. the plackett burman design (pbd) of experiments was used to test the relative importance of the variables affecting production such as moisture content, age of spore, inoculum size, initial ph of substrate, methanol concentration, incubation temperatur...

Influences of phenol, α-naphtol and β-naphtol, which are toxic chemicals, on citric acid biosynthesis and biomass in the artificial culture setting of Aspergillus niger using batch fermenter are examined in the most favorable fermentation conditions, and a model is proposed. Addition of certain concentrations of phenol, α-naphtol and β-naphtol to the culture reduces the citric acid production. ...

The present investigation deals with the kinetics of submerged citric acid fermentation by Aspergillus niger using blackstrap molasses as the basal fermentation media. A laboratory scale stirred fermentor of 15-L capacity having working volume of 9-L was used for cultivation process and nutritional analysis. Among the 10 stock cultures of Aspergillus niger, the strain GCBT7 was found to enhance...

The inherent non-linearity of citric acid fermentation from Aspergillus niger renders its control difficult, so there is a need to fine-tune the bioreactor performance for maximum production of citric acid in batch culture. For this, fuzzy logic is becoming a popular tool to handle non-linearity of a batch process. The present manuscript deals with fuzzy logic control of citric acid accretion b...

The present study is concerned with the effect of low pH on continuous citric acid fermentation by Aspergillus niger strain SK-17. Microbial cultivations were carried out in a stainless steel stirred bioreactor of 15 L total capacity. The bioconversion of glucose to citric acid at low pH was investigated on cellulose fabric. Sucrose solution (100 g/l) was made to flow through capillaries of a v...

Citric acid is a commodity chemical produced and consumed throughout The World. It is used mainly in the food and beverage industry, primarily as an acidulant. Although it is one of the oldest industrial fermentations, its World production is still in rapid increasing. Global production of citric acid in 2007 was over 1.6 million tones. Biochemistry of citric acid fermentation, various microbia...

The mutant strain of Aspergillus niger NG-110 was evaluated for the present investigation of citric acid production. The cultural conditions optimized during the course of study were pH and K4Fe(CN)6, K2HPO4 and CaCl2 concentrations. Cane-molasses was utilized as the basal fermentation medium. The mutant NG-110 produces maximal amount of citric acid when the pH of the medium was 6. When the con...

The potential role of a new energy efficient fermentation technology has been receiving growing attention in past 4 decades. Carboxylic acids such as propionic acid, lactic acid, citric acid, tartaric acid, itaconic acid, butyric acid and nicotinic acid etc. have been used as the most efficient fermentation chemicals. This paper presents a state-of-art review on the development of the separatio...

In view of the often-cited theory that citric acid accumulation is caused by an inhibition of aconitase activity, the equilibrium of the reaction of aconitase was investigated by comparing in vivo steady-state concentrations of citrate and isocitrate in Aspergillus niger grown under various citric acid-producing conditions. With the equilibrium catalyzed by the A. niger enzyme in vitro, similar...