Application of Plackett Burman design for citric acid production from pretreated and untreated wheat straw

作者：Khosravi Darani Kianoosh^*; Zoghi Alale; Alavi Sayed Abolhasan; Fatemi Sayed Safa Ali

来源：Iranian Journal of Chemistry and Chemical Engineering (International English Edition), 2008, 27(1): 91-104.

• solid state fermentation
• citric acid production
• pretreatment
• wheat straw
• Plackett-Burman design

A solid state fermentation method was used to utilize wheat straw as substrates for citric acid production by, using Aspergillus niger A TCC 9142. The Plackett Burman design (PBD) of experiments was used to test the relative importance of the variables acting production such as,Ore moisture content, age of spore, inoculum size, initial pH of substrate, methanol concentration, incubation temperature and time, as well as initial sugar concentration, steam time and type of solvent. In best condition, the microorganism produced 47 g citric acid per kg dry crude wheat straw, with yield of 93 % based on the amount of fermentable sugar consumed The effect of pretreatment of wheat straw with HCl, NaOH and urea on the yield of production was also investigated by using PRD. Acid, alkaline and urea pretreatment of wheat straw increased citric acid concentration to 115, 85.0 and 109.5 g/kg of dry wheat straw and yield to 97, 97 and 96 % (respectively) based on available sugar consumed Finally, up scaling was achieved to a 20-L solid state fermentor (tray bioreactor) in which moisture was constant in gas, phase and acid pretreated wheat straw was selected as the most efficient pretreated substrate. The produced acid concentration and yield in fermentor was 60.53 g/kg of dry wheat straw and 2.11 g/kg.day, respectively.

• 出版日期2008